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Caesarea

Aerial View of Caesarea Aerial View of Caesarea

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Used with permission from Biblewalks.com


Names

Transliterated Name Language Name
Caesarea
Caesarea Maritima
Keysariya Hebrew קֵיסָרְיָה
Qesarya Hebrew קֵיסָרְיָה
Qisri Rabbinic Sources
Qisrin Rabbinic Sources
Qisarya Arabic قيسارية
Qaysariyah Early Islamic Arabic قايساريياه
Caesarea near Sebastos Greek and Latin sources
Caesarea of Straton Greek and Latin sources
Caesarea of Palestine Greek and Latin sources
Caesarea Ancient Greek Καισάρεια
Straton's Tower
Strato's Tower
Stratonos pyrgos Ancient Greek
Straton's Caesarea
Introduction
Introduction

King Herod built the town of Caesarea between 22 and 10/9 BCE, naming it for his patron - Roman Emperor Caesar Augustus. The neighboring port was named Sebastos - Greek for Augustus (Stern et al, 1993). Straton's Tower, a Phoenician Port city, existed earlier on the site. When the Romans annexed Judea in 6 CE, Caesarea became the headquarters for the provincial governor and his administration (Stern et al, 1993). During the first Jewish War, Roman General Vespasian wintered at Caesarea and used it as his support base (Stern et al, 1993). After he became Emperor, he refounded the city as a Roman colony. Caesarea is mentioned in the 10th chapter of the New Testament book of Acts as the location where, shortly after the crucifixion, Peter converted Roman centurion Cornelius - the first gentile convert to the faith. In Early Byzantine times, Caesarea was known for its library and as the "home-town" of the Christian Church historian and Bishop Eusebius. After the Muslim conquest of the 7th century, the city began to decline but revived again in the 10th century (Stern et al, 1993). Crusaders ruled the city for most of the years between 1101 and 1265 CE (Stern et al, 1993). After the Crusaders were ousted, the town was eventually leveled in 1291 CE and remained mostly desolate after that (Stern et al, 1993).

Identification

Herod the Great named the port city he built on the Mediterranean coast Caesarea, to honor his patron, the emperor Caesar Augustus. He called the neighboring port Sebastos, Greek for" Augustus." The site is located on the Sharon coast, about midway between Haifa and Tel Aviv (map reference 1399.2115). The site's ancient name has survived into modern times in the Arabic Qaisariya. Rabbinic sources reproduced Caesarea as Qisri or Qisrin. Because it was only one of many Caesareas, Greek and Latin sources often specify Caesarea as near (the harbor) Sebastos, Caesarea of Straton, or (more commonly) Caesarea of Palestine. The emperor Vespasian granted Caesarea the rank of Roman colony, making it Colonia Prima Flavia Augusta Caesariensis, and Severus Alexander gave it the title Metropolis of the province Syria Palaestina. The name Caesarea Maritima, widely used today, was apparently unknown in antiquity. Straton's Tower (Στρατωνος Πνργος), a Phoenician port town, existed earlier on the site. The name is Greek for Migdal Shorshon, its equivalent in rabbinic texts. It is a common type of toponym meaning a fortified town, not a bastion or lookout tower, as some have thought. Whatever the meaning of Shorshon, in local legend Straton was a Greek hero, and it was he, not Herod, who founded Caesarea, which has thus also been called Straton's Caesarea.

History

Modern scholars suggest that the historical Straton was either a general in the Ptolemaic army in the beginning of the third century BCE or one of two Phoenicians named 'Abdashtart who ruled Sidon in the fourth century BCE. Recent ceramic finds do support limited commercial activity at the site this early, but the earliest reference to Straton's Tower is in a papyrus from the Zenon archive (P Cairo 59004) (259 BCE), which also attests an active harbor. The town flourished in the third century BCE (ceramic evidence) and especially in the later second century BCE, when the local tyrant, Zoilos, held it against the expanding Jewish kingdom (Josephus, Antiq. XIII, 324), perhaps fortifying it with the "city wall of Straton's Tower" mentioned in a rabbinic source (Tosefta Shevi'it IV, 11). The rulers of Straton's Tower apparently developed at least two protected harbors, cut into the sandstone bedrock of the coast in characteristic Hellenistic fashion - λιμην κλειστος (close haven).

The town finally passed to Alexander Jannaeus in about 100 BCE (Josephus, Antiq. XIII, 334~335). During forty years of Hasmonean rule, Straton' s Tower probably acquired a Jewish population, but the rabbis excluded the town itself (though not its territory) from the borders of Palestine (Tosefta Shevi'it IV, 11). To weaken the Hasmonean kingdom, Pompey annexed Straton's Tower and other coastal towns to Roman Syria in 63 BCE (Antiq. XIV, 76; War I, 156). The town was in a state of decay when Octavian, the future Caesar Augustus, restored it to the Jewish state in 31 BCE (Antiq. XV, 217; War I, 396).

Between 22 and 10/9 BCE, Herod built Caesarea on the site of Straton's Tower. Josephus praises the king's lavish construction, which included a theater and an amphitheater, a royal palace, the marketplace (agora), streets on a grid plan, and especially the harbor (War I, 408~414; Antiq. XV, 331~ 337; XVI, 136~141). Above the old main harborof Straton's Tower and just to the east, he created a spacious temple platform. Upon this platform he erected a temple dedicated to the goddess Roma and to the deified Emperor Augustus. Herod appears to have resettled the site with Jews as well as with Greek-speaking pagans. Nevertheless, Caesarea became a typical Greek city-state (polis) of the Hellenistic age, ruled by a city council and magistrates under a resident royal general. In the Herodian state, this city was a pagan and Greek counterweight to Jewish Jerusalem. The new harbor, Sebastos, like the city itself, emphasized Herod's links with his Roman patron, and it offered the only all-weather haven on the Mediterranean coast o his kingdom. Sebastos consisted of a renovated inner harbor, the old rock-cut main anchorage of Straton's Tower, and a much larger outer harbor basin that extended westward from the shore, encompassed within massive constructed breakwaters designed to protect moored ships from the powerful coastal surge. As vessels approached from the northwest, they passed colossal statues of the emperor's family elevated on columns that guided mariners to the harbor entrance. Visible from much farther out at sea was the harbor's lighthouse tower, named after Drusus, the emperor's current heir apparent. Josephus also mentions barrel-vaulted warehouses designed to accommodate goods passing through the harbor (War I, 413; Antiq. XV, 337). It seems that Sebastos retained its royal administrative status, unlike the municipal anchorage at the bay south of it, until it was handed over to the people of the city in about 70 CE.

When the Romans annexed Judea to the empire in 6 CE, they made Caesarea the headquarters of the provincial governor and his administration. A Latin inscription found in the theater records that one of these, Pontius Pilate, prefect of Judea, dedicated a temple at Caesarea to the emperor Tiberius (AE 1963, no. 104). The city remained the capital of Judea, later called Palaestina, until the end of classical antiquity.

In 66 CE, on the eve of the First Jewish Revolt against Rome, the pagan majority massacred most of Caesarea's Jews (War II, 457). During the revolt, the Roman commander, Vespasian, wintered at Caesarea and used it as his main support base. After he became emperor, in gratitude for its loyalty, he refounded the city as a Roman colony. Caesarea became an outpost of Roman culture. Western-type duumviri headed the government and decurions (municipal senators) formed the city council. Many inscriptions from Caesarea's first three centuries are in Latin. Hostile to Caesarea, the rabbis called it "daughter of Edom," meaning "daughter of Rome," and they denied that Caesarea and Jerusalem could prosper at the same time.

In the second and third centuries, the city continued to profit from links with the Roman emperors. Hadrian, who may have paid Caesarea an imperial visit in the summer of l30, expanded its aqueduct system and may have built the city's stone circus. In response, the Caesareans dedicated a temple to Hadrian, and coins from the local mint depicted him as the colony's founder. Other imperial visitors were Septimius Severus, in 199 or 201, and perhaps Severus Alexander, in 231-232. The former founded the city's famous Pythian games, while it was Alexander who gave Caesarea the title metropolis. Christianity took at Caesarea within a few years of the Crucifixion, when Saint Peter converted the Roman centurion Cornelius (Acts 10). Indeed, this city may have harbored the first gentile Christians. Nevertheless, the virtual extinction of the Jewish community in 66 apparently implicated most Christians as well, and it is only from the later second century that there is a renewed record of a Christian church, with its own bishop. In the same period, Jews resettled in Caesarea, attracted by economic advantages. By 250, the city boasted both a celebrated rabbinic academy and the Christian school of Origen, the outstanding scholar and theologian who assembled an unparalleled library and compiled the hexapla text of the Bible. In the towns and villages of Caesarea's countryside, the population was heavily Jewish and Samaritan.

With the advent of the Christian Roman Empire (fourth-seventh centuries), Caesarea's population and economy expanded, as in the rest of Palestine. A new fortification wall enclosed far more urban space. The authorities built an additional (low-level) aqueduct system, and they continued to replace the city's street pavements following Herod's original grid plan. When Christianity became the dominant religion, a church replaced Herod's temple to Roma and Augustus on the temple platform.

In this period Caesarea remained a metropolis, or provincial capital. In 530, the Roman emperor Justinian promoted the governor stationed at Caesarea to proconsul because of the city's famous past and because it presided over a province filled with famous cities, including the one where "Jesus Christ ... had appeared on earth" (Justinian, Novella 103). The city's bishop also ranked as metropolitan of Palestine and the Caesarean see kept this prerogative even after 451, when the archbishop of Jerusalem obtained the rank of patriarch. The most famous of Caesarea's bishops was the ecclesiastical historian and apologist Eusebius (bishop c. 315-339), who recorded Christian martyrdoms in the city's amphitheater under the last pagan emperors. On the Jewish side, his contemporary was Rabbi Abbahu, who taught his daughters Greek, visited the city's baths, and maintained excellent relations with the pagan authorities. Another product of the city's learned culture was the historian Procopius of Caesarea (sixth century).

By 500, tectonic action and the coastal surge had reduced parts of the breakwaters of Herod's harbor to submerged reefs that were a hazard to navigation. The emperor Anastasius ( 492-517) undertook a major building campaign to restore Sebastos (Procopius of Gaza, Panegyricus in imperatorem Anastasium XIX, PG 87, col. 2817), and this helped Caesarea reach its pinnacle of prosperity in the sixth century. In the meantime, however, relations deteriorated between the city's Christian majority and its Samaritan and Jewish minorities. In 484, rebellious Samaritans burned Caesarea's Church of Saint Procopius. The major revolt of 529-530, when thousands of Samaritans died, fled, or were enslaved, left the territory of Caesarea denuded of her peasant farmers, a serious economic blow (Procopius of Caesarea, Arcana XI, 14-33). In 555, Samaritans - this time allied with the Jews - again burned Christian churches at Caesarea, together with the palace of the Roman governor (J. Malalas, Chron. XVIII, 487-488). These troubles presaged the invasions of the seventh century, when non-Christian minorities generally sided with the enemy. In 614, a Persian army attacked Caesarea, but the city capitulated without serious resistance. The Roman armies returned for a brief period after 628, but in 641 or 642 Caesarea fell to an Arab army after a seven-month siege.

During the next two centuries Caesarea suffered heavily from depopulation, natural building collapse, and stone robbing, and the harbors fell into disuse. By the tenth century, however, Caesarea reemerged, a prosperous town but on a much smaller scale. The geographers el-Muqaddasi and Nasiri-Khusrau mention flourishing gardens and orchards, a fortification wall, and a Great Mosque apparently situated on what had been Herod's temple platform (PPTS III, 3, 55; IV, 1, 20). In 1101, the Frankish king Baldwin I of Jerusalem and the Genoese fleet conquered Caesarea after a brief siege and established a Crusader principality. It lasted, despite periods of reconquest, until 1265. A Christian church replaced the Great Mosque on the temple platform. In 1251-1252, the French king Louis IX ("Saint Louis") labored on the fortifications with his own hands, as an act of penance. Fourteen years later, the Egyptian sultan Baybars stormed Caesarea, and in 1291 his successor leveled it and other Crusader castles along the Levantine coast to prevent their falling into enemy hands. From time to time a squatter settlement existed among the ruins after 1291, but Caesarea mostly remained desolate.

History of Excavations

Early Exploration and Excavations

Caesarea is a large site, comprising about 235 a. within its semicircular perimeter wall. In the eighteenth and nineteenth centuries European travelers, such as R. Pococke and V. Guerin, published more-or-less accurate descriptions of the site. In 1873, C. R. Conder and H. H. Kitchener mapped and described it as part of the Survey of Western Palestine, noting, for example, the aqueducts, the semicircular (outer) perimeter wall, the medieval fortifications, and the theater. Over the next ninety years there were only chance finds. In 1945, J. Ory,forthe Mandatory Department of Antiquities, and M. Avi-Yonah, in 1956 and 1962, for the Israel Department of Antiquities and Museums, explored the meager remains of a synagogue revealed during winter storms along the northern seashore. In 1951, S. Yeivin excavated a marble-paved esplanade east of the Crusader city for the department, where a tractor from Kibbutz Sedot Yam had struck a colossal porphyry statue. In 1955, a large mosaic pavement on a ridge to the northeast of ancient Caesarea was also exposed accidentally.

Large-scale, systematic explorations at Caesarea date only from 1959, the first of five seasons of the Missione Archeologica ltaliana directed by A. Frova. This team studied part of the semicircular (outer) perimeter wall, demonstrating its date to be Byzantine, and exposed, for the first time, the northern segment of an inner perimeter wall, which the Missione considered Herodian. It also examined a "Christian building" to the northeast of the site and completely excavated the Herodian-Roman theater and the massive fortezza (fortress) that incorporated the ruins of the theater in the Byzantine period. During most of the same years (1960-1964) A. Negev, on behalf of the National Parks Authority, cleared the Crusader moats surrounding the present medieval city. Negev exposed numerous ancient and medieval ruins, including the facade of the temple platform and the triple-apsed Crusader basilica above it. Negev also excavated to the north of the medieval city, between it and the inner perimeter wall, where he exposed part of the Hellenistic town, and to the south of the southern Crusader moat, where he found the building he identified as the library of Origen and Eusebius. Farther north, just inland from the coast, Negev exposed and studied 300 m of the high-level aqueduct.

The Joint Expedition to Maritime Caesarea, comprising teams from twenty-one colleges and universities in the United States and Canada, began exploring the site in 1971, under the direction of R. Bull, 0. Storvick, and E. Krentz. In twelve seasons, this project excavated many sites outside the medieval city, mainly in fields A and B to the east; C, K, L, M, and N to the south; and G to the north, within the inner perimeter wall. Among the Joint Expedition's main goals was to recover the grid plan of streets laid out by Herod. In 1974, J. H. Humphrey, under Joint Expedition auspices, dug several trenches in the circus. During the same decade, in 1975-1976 and 1979, L. I. Levine and E. Netzer, representing the Hebrew University's Institute of Archaeology, explored the west-central part of the medieval city and what Netzer calls the Promontory Palace, which extends seaward to the northwest of the theater.

In more recent rescue excavations, R. Reich and M. Peleg uncovered a south gate in the ancient semicircular perimeter wall in Kibbutz Sedot Yam (1986), adjacent to the site on the south, andY. Porath studied the south gate in the medieval wall and part of the wall itself (1989-1990). Porath has also conducted extensive research on Caesarea's aqueducts. In 1990, Netzer renewed his work on the Promontory Palace. In 1989-1990, A. Raban and K. Holum organized the Combined Caesarea Expeditions (CCE), an international amphibious effort to explore major sectors of the ancient site. To the south of the medieval city, the Combined Caesarea Expeditions have begun work in area KK, the next insula (city block) to the south of the Joint Expedition's field C. The objective here is to explore the evolution of an urban neighborhood throughout antiquity. CCE is also excavating in area I, the inner harbor, and area TP, the temple platform, in an effort to link the harbor with what was apparently the monumental center of both the ancient and medieval city.

Caesarea is also a rare maritime site where subsurface remains of a major ancient harbor lie relatively undisturbed by postmedieval harbor construction and uncluttered by the detritus of modern commerce. In 1960, E. Link, one of the pioneers of underwater exploration, conducted a marine survey that first identified the ruins ofSebastos, Herod's great harbor. Bad weather and difficult seas limited Link's success, however, and it was not untill976 that Haifa University's Center for Maritime Studies began sustained research on Caesarea's harbors. In that year, Raban headed an intensive underwater survey. Following three additional survey and training seasons (1978-1980), R. Hohlfelder, J. Oleson, and later R. Vannjoined Raban as codirectors of the international Caesarea Ancient Harbour Excavation Project (CAHEP). During the 1980s, this team recovered the design and construction techniques Herod used for Sebastos and examined lesser harbors to the north and south of it, as well as some of the numerous shipwrecks nearby. R. Stieglitz, another project co-director, explored harbor installations on land and remains ofStraton's Tower. CCE is continuing work on Sebastos

IAA Excavations

Large-scale archaeological excavations were carried out at Caesarea from 1992 to 1998 by the Israel Antiquities Authority (IAA); they were directed by Y. Porath. The project included the excavation of a 100–150-m-wide strip along the coast between the theater complex to the south and the excavations of the Combined Caesarea Expeditions (CCE) to the north; the western part of the temple platform and the area between this platform and the eastern quay of the port of Sebastos; both sides of the southern Crusader wall (continuing the salvage excavations carried out in 1989); the bottom of the Crusader moat (cleared in the 1960s by A. Negev), from the southern gateway to the northern gateway; and the area southwest of the theater. In addition, salvage excavations were conducted within the area demarcated by the Byzantine wall; in structures outside the wall; on the necropolis; in agricultural areas to the east, north, and south of the city; and along the aqueducts that carried water to Caesarea from outside the city.

The Combined Caesarea Expeditions Excavations

During the 1990s the face of ancient Caesarea underwent dramatic change as excavations on an unprecedented scale exposed much more of the site and resolved earlier puzzles and misconceptions. The Combined Caesarea Expeditions (CCE) organized in 1989 by A. Raban, of the Recanati Institute for Maritime Studies at the University of Haifa, and K. G. Holum, of the University of Maryland, continued work through much of the decade and, on a more limited scale, into the new millennium. In 1993, J. Patrich joined the CCE directorate on behalf of the University of Haifa. Inside the Old City, K. Holum directed excavations on the temple platform (area TP) and in a warehouse quarter north of the inner harbor (area LL). A. Raban led excavations at the presently land-locked inner harbor and its eastern quay (area I), and at two sites along the southern edge of the temple platform (areas Z and TPS). J. Patrich excavated south of the Crusader city in areas CC, NN, and KK. In area KK, he uncovered six warehouse units, while area CC, formerly field C of the Joint Expedition to Caesarea Maritima (JECM), contained a government complex that accommodated the Roman provincial procurator and later the governor of Byzantine Palestine. The CCE team also devoted effort to area CV, the western side of the area CC vaults, and its maritime unit conducted underwater excavations in the harbor.

Underwater Excavations

The CAHEP (Caesarea Ancient Harbour Excavation Project) consortium, led by the Recanati Institute for Maritime Studies at the University of Haifa, in collaboration with the University of Colorado (led by R. L. Hohlfelder), the University of Maryland (led by R. L. Vann), and the University of Victoria, British Columbia (led by J. P. Oleson), was succeeded by the maritime unit of the CCE, a collaborative project of the University of Haifa (led by A. Raban) and McMaster University (led by E. G. Reinhardt). The ongoing project conducts an annual field season with student volunteers from both institutions as well as others from around the world. The focus of the underwater research has shifted lately toward geoarchaeology, in an attempt to comprehend the history of maritime activity at Caesarea and the demise of Sebastos in the context of environmental changes and topographical alternations on the waterfront.

Maps, Aerial Views, Plans, Sections, Drawings, and Photos
Maps, Aerial Views, Plans, Sections, Drawings, and Photos

Maps

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  • Fig. 5 The Caesarea region from Galili et al (2021)

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  • Fig. 5 The Caesarea region from Galili et al (2021)

Aerial Views

Normal Size

  • Aerial Photo of Caesarea from 1918 from castellorient.fr
  • Fig. 5.3 Aerial photograph of Caesarea showing projected ancient coastline from Raban et al. (2009)
  • Fig. 5.71 Aerial view of Sebastos from the south with the demarcation of the studied areas in the intermediate basin from Raban et al. (2009)
  • Caesarea in Google Earth
  • Caesarea on govmap.gov.il

Magnified

  • Aerial Photo of Caesarea from 1918 from castellorient.fr
  • Fig. 5.3 Aerial photograph of Caesarea showing projected ancient coastline from Raban et al. (2009)
  • Fig. 5.71 Aerial view of Sebastos from the south with the demarcation of the studied areas in the intermediate basin from Raban et al. (2009)
  • Caesarea in Google Earth
  • Caesarea on govmap.gov.il

Plans, Sections, Drawings, and Photos

Site Plans

Normal Size

  • Fig. 1 Sketch plan of Caesarea Maritima from Toombs (1978)
  • Aqueducts in the vicinity of Caesarea from Stern et. al. (2008)
  • Map of Caesarea showing excavation areas from Stern et. al. (2008)
  • Herodian Caesarea from Stern et. al. (2008)
  • Byzantine Caesarea from Stern et. al. (2008)
  • Fig. 1 Roman and Crusader Caesarea from Ad et al (2017)
  • Fig. 1 Caesarea with principal sites mentioned by Dey et al(2014)
  • Fig. 1.9 Plan of early Islamic Caesarea from Whitcomb (2016)
  • Fig. 3.5 Site map of the various excavated areas from Raban et al. (2009)
  • Fig. 2.24 Artist's rendering of view of the central and southern parts of Straton's Tower at the time of Zoilus from Raban et al. (2009)
  • Fig. 3.9 General plan of Herodian structures at Caesarea from Raban et al. (2009)
  • Fig. 2 Map of the ancient city of Caesarea from Raphael and Bijovsky (2014)

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  • Fig. 1 Sketch plan of Caesarea Maritima from Toombs (1978)
  • Aqueducts in the vicinity of Caesarea from Stern et. al. (2008)
  • Map of Caesarea showing excavation areas from Stern et. al. (2008)
  • Herodian Caesarea from Stern et. al. (2008)
  • Byzantine Caesarea from Stern et. al. (2008)
  • Fig. 1 Roman and Crusader Caesarea from Ad et al (2017)
  • Fig. 1 Caesarea with principal sites mentioned by Dey et al(2014)
  • Fig. 1.9 Plan of early Islamic Caesarea from Whitcomb (2016)
  • Fig. 3.5 Site map of the various excavated areas from Raban et al. (2009)
  • Fig. 2.24 Artist's rendering of view of the central and southern parts of Straton's Tower at the time of Zoilus from Raban et al. (2009)
  • Fig. 3.9 General plan of Herodian structures at Caesarea from Raban et al. (2009)
  • Fig. 2 Map of the ancient city of Caesarea from Raphael and Bijovsky (2014)

Area Plans

Harbour

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  • Fig. 1 Roman and Crusader Caesarea from Ad et al (2017)
  • Fig. 1 View of ancient harbor of Caesarea from Reinhardt and Raban (1999)
  • Fig. 4 The Roman, Herodian harbor of Caesarea from Galili et al (2021)
  • Fig. 2.3 Excavation Areas in NW part of Caesarea (the harbor) from Raban et al. (2009)
  • Fig. 2.22 Reconstruction plan of the the location of the harbour basins of Straton's Tower and the line of the city walls from Raban et al. (2009)
  • Fig. 2.23 Schematic map of the inner basin c. 110 BCE from Raban et al. (2009)
  • Fig. 2.25 General plan of the excavations at the north side of the intermediate harbour basin from Raban et al. (2009)
  • Fig. 5.48 Schematic block diagram of the main mole during phases 2, 3 from Raban et al. (2009)
  • Fig. 5.69 Suggested sketch plan of Sebastos at its final phase of construction from Raban et al. (2009)

Magnified

  • Fig. 1 Roman and Crusader Caesarea from Ad et al (2017)
  • Fig. 1 View of ancient harbor of Caesarea from Reinhardt and Raban (1999)
  • Fig. 4 The Roman, Herodian harbor of Caesarea from Galili et al (2021)
  • Fig. 2.3 Excavation Areas in NW part of Caesarea (the harbor) from Raban et al. (2009)
  • Fig. 2.22 Reconstruction plan of the the location of the harbour basins of Straton's Tower and the line of the city walls from Raban et al. (2009)
  • Fig. 2.23 Schematic map of the inner basin c. 110 BCE from Raban et al. (2009)
  • Fig. 2.25 General plan of the excavations at the north side of the intermediate harbour basin from Raban et al. (2009)
  • Fig. 5.48 Schematic block diagram of the main mole during phases 2, 3 from Raban et al. (2009)
  • Fig. 5.69 Suggested sketch plan of Sebastos at its final phase of construction from Raban et al. (2009)

Area TP - Temple/Octogonal Church

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  • Fig. 1.10 Drawing of the Temple Platform at Caesarea from Whitcomb (2016)
  • Plan of Area TP containing the Octagonal Church from Stern et. al. (2008)

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  • Fig. 1.10 Drawing of the Temple Platform at Caesarea from Whitcomb (2016)
  • Plan of Area TP containing the Octagonal Church from Stern et. al. (2008)

mid 7th century Irrigated Garden

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  • Fig. 2 Plan of the mid-7th century irrigated garden from Taxel (2013)

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  • Fig. 2 Plan of the mid-7th century irrigated garden from Taxel (2013)

Area CV

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  • Fig. 130 Area CV block plan from Raban et al. (1993 v. II)
  • Fig. 129 Aerial View of Area CV from Raban et al. (1993 v. II)

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  • Fig. 130 Area CV block plan from Raban et al. (1993 v. II)
  • Fig. 129 Aerial View of Area CV from Raban et al. (1993 v. II)

Area LL

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  • Fig. 1D Aerial view of site LL and southern part of the Upper aqueduct from Everhardt et. al. (2023)
  • Fig. 1E Aerial view of site LL showing locations of cores, baulk, and collapsed corridor from Everhardt et. al. (2023)
  • Fig. 3 Early phases Plan of Area LL from Ad et al (2018)
  • Fig. 8 Wall Collapse in Stratum VI (Umayyad) from Ad et al (2018)
  • Fig. 3 Sections of Cores C1 and C2 and the Southern Baulk from Everhardt et. al. (2023)
  • Fig. 2B Destruction layer(s) showing building stones suspended in anomalous sands from Everhardt et. al. (2023)
  • Fig. 2C Archaeological fill directly underlying anomalous deposit along with inset of fire-burnt stones from Everhardt et. al. (2023)
  • Fig. 4 Lab Analysis of Core C1 from Everhardt et. al. (2023)
  • Fig. 5 Lab Analysis of Southern Baulk from Everhardt et. al. (2023)
  • Fig. 8 Projected direction of tsunami surge from Everhardt et. al. (2023)

Magnified

  • Fig. 1D Aerial view of site LL and southern part of the Upper aqueduct from Everhardt et. al. (2023)
  • Fig. 1E Aerial view of site LL showing locations of cores, baulk, and collapsed corridor from Everhardt et. al. (2023)
  • Fig. 3 Early phases Plan of Area LL from Ad et al (2018)
  • Fig. 8 Wall Collapse in Stratum VI (Umayyad) from Ad et al (2018)
  • Fig. 3 Sections of Cores C1 and C2 and the Southern Baulk from Everhardt et. al. (2023)

Field O - Synagogue

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  • Fig. 3 Plan of the Stratum IV synagogue from Raphael and Bijovsky (2014)

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  • Fig. 3 Plan of the Stratum IV synagogue from Raphael and Bijovsky (2014)

Offshore Caesarea - Area W, Location of Cores and Seismic Survey used to examine tsunami deposits

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  • Fig. 2 Satellite image showing locations of Caesarea Cores 1, 2, and 5, Area W, and shot points of the 2011 CHIRP survey from Goodman-Tchernov and Austin (2015)

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  • Fig. 2 Satellite image showing locations of Caesarea Cores 1, 2, and 5, Area W, and shot points of the 2011 CHIRP survey from Goodman-Tchernov and Austin (2015)

Photos

Normal Size

  • Fig. 132 South Balk of Area CV/1 showing five phases from Raban et al. (1993 v. II)
  • Fig. 133 Structural collapse and crushed pottery in Area CV/2 from Raban et al. (1993 v. II)
  • Fig. 1 Avi-Yonah at the spot of discovery of the hoard from Raphael and Bijovsky (2014)
  • Fig. 4 Excavation of the Field O synagogue from Raphael and Bijovsky (2014)

Magnified

  • Fig. 132 South Balk of Area CV/1 showing five phases from Raban et al. (1993 v. II)
  • Fig. 133 Structural collapse and crushed pottery in Area CV/2 from Raban et al. (1993 v. II)
  • Fig. 1 Avi-Yonah at the spot of discovery of the hoard from Raphael and Bijovsky (2014)
  • Fig. 4 Excavation of the Field O synagogue from Raphael and Bijovsky (2014)

Caesarea Tsunamogenic Site
Caesarea Tsunamogenic Site



Textual Chronology
Eusebius Mystery Quake - 126-130 CE

Discussion

Discussion

363 CE Cyril Quake

Discussion

Discussion

749 CE Sabbatical Year Earthquake - Holy Desert Quake

Discussion

Discussion

Archaeoseismic and Tsunamigenic Chronology
Stratigraphy

Inner Harbor

 Stratigraphy/Chronology - Inner Harbor Areas I/1 - Z/2

Raban et al. (1989 Vol. 1)


Crusader Market and Area LL ("the warehouse") by Ad et al. (2017, 2018)

Stratum Period
I Modern
II Late Ottoman (Bosnian)
IIIa Crusader (Louis IX)
IIIb Crusader (pre-Louis IX)
IV Fatimid
V Abbasid
VI Umayyad
VII Late Byzantine/Early Umayyad
VIII Late Byzantine
IX Early Byzantine
X Late Roman
XI Roman
XII Early Roman
XIII Herodian

Areas CC, KK, and NN

 Stratigraphy of Areas CC, KK, and NN

Stern et. al. (2008)


Starting Gates of the Hippodrome

 Phases of the Starting Gates of the Hippodrome

Stern et. al. (2008)


Toombs (1978)

Entire Site Summary

  • Toombs (1978) developed a stratigraphic framework for Caesarea after 4 seasons of excavations using the destruction layers overlying the latest Byzantine occupation as the stratigraphic key. The framework was developed primarily on balk sections from four fields - A, B, C, and H. It is considered most accurate for the Byzantine and Arab phases and least accurate for Late Arab and Roman levels.
  • Dates with an asterisk (*) were derived from Note 4 in Toombs (1978:232)
  • Sketch plan of Caesarea Maritima from Toombs (1978) .
Phase Period Date Comments
I Modern
II Crusader 1200-1300 CE
III.1 Late Arab 900*-1200 CE
III.2 Middle Arab
Abbasid
750-900* CE
III.3 Early Arab
Umayyad
640-750 CE
IV Byzantine/Arab 640 CE In A.D. 640 Caesarea fell to Arab invaders. This time the destruction was complete and irretrievable. Battered columns and the empty shells of buildings stood nakedly above heaps of tangled debris.
V Final Byzantine 614-640 CE In A.D. 614 Persian armies captured Caesarea, but withdrew by A.D. 629. This invasion caused widespread destruction and brought the Main Byzantine Period to a close, but recovery was rapid and the city was restored
VI.1 Main Byzantine 450/550*-614 CE
VI.2 Main Byzantine 330 - 450/550* CE
VII.1 Roman 200*-330 CE It seems probable that during the Late Roman Period a major catastrophe befell the city, causing a partial collapse of the vaulted warehouses along the waterfront, and the destruction of major buildings within the city. Such a city-wide disaster alone would account for the rebuilding of the warehouse vaulting and the buildings above it, as well as the virtual absence of intact Roman structures in the city proper.
VII.2 Roman 100*-200* CE
VII.3 Roman 10 BCE - 100* CE

Entire Site with comparisons between areas

  • Toombs (1978) developed a stratigraphic framework for Caesarea after 4 seasons of excavations using the destruction layers overlying the latest Byzantine occupation as the stratigraphic key. The framework was developed primarily on balk sections from four fields - A, B, C, and H. It is considered most accurate for the Byzantine and Arab phases and least accurate for Late Arab and Roman levels.
  • Sketch plan of Caesarea Maritima from Toombs (1978) .
Stratigraphic Framework for Caesarea by Toombs (1978) Figure 4

Stratigraphic analysis of the results of the first four seasons at Caesarea, tabulated by Field.

Toombs (1978)

Summary of Tsunamigenic Events at Caesarea and Jisr al-Zikra

Core Data from Goodman-Tchernov and Austin (2015) and Tyuleneva et al (2017)

Table from Raphael and Bijovsky (2014)

Table 1

Earthquakes or tsunamis noted on the coast of Israel

Click on Image to open in a new tab

Raphael and Bijovsky (2014)


Shallow Seismic Survey and evolution of the harbor over time

Figures

Figures

Normal Size

  • Fig. 6 - Seismic Reflectors and evolution of Caesarea's harbor from Goodman-Tchernov and Austin (2015)

Magnified

  • Fig. 6 - Seismic Reflectors and evolution of Caesarea's harbor from Goodman-Tchernov and Austin (2015)

Discussion

Goodman-Tchenov and Austin (2015) mapped the tsunami horizons from a high frequency seismic reflection survey (2.5-5.5 kHz. Chirp source) which produced markers ~4-5 meters below the sea floor before sea bottom multiples obscured the image. Shot spacing was ~ 5 meters. The fold of the survey is not reported. It may have been single fold. Velocity control below the seafloor is also unreported. The time-depth conversion in Figure 6 above may have been based on correlating seismic markers to core horizons. Reflector 'A' was correlated to the 5th-8th century tsunami deposit. Reflector 'B' was correlated to a 1st-2nd century CE tsunami deposit which they associate with the 115 CE Trajan Quake although I think it more likely correlates to localized shelf collapse due to the the early 2nd century CE Incense Road Quake or an unknown event. Structure maps constructed from time horizons of Reflectors A and B show the apparent presence of backflow channels from both tsunami events with 3-6 channels associated with the 5th - 8th century CE horizon and 1-2 channels associated with the 1st-2nd century CE horizon. The presence of more identifiable backflow channels on Reflector A (5th - 8th century CE) than Reflector B (1st - 2nd century CE) was interpreted to be a result of harbor degradation by Byzantine-Islamic time resulting in less flow impediments from man-made structures. This appears to be supported by archeological evidence which showed more ships anchoring at sea during this time.

Santorini Eruption Tsunami - 1630-1550 BCE

Discussion

Discussion

References
Steele et al. (2024)

Abstract

The construction of harbours along high energy nearshore environments, which commonly include the emplacement of hard structures both as central features (e.g., piers, jetties) as well as protective measures (e.g., wave breakers, coastal armouring), can alter coastlines in a multitude of ways. These include reconfiguring the coast’s morphology, introducing or redistributing exogenous and endogenous materials, and changing localized environmental substrate and structural conditions; and, as a result, impact the associated ecological communities. With growing coastal populations and associated coastal development, concerns over the long-term consequences of such projects are of global interest. Caesarea Maritima, a large-scale, artificially constructed ancient harbour built between 21 and 10 BCE, provides a rare opportunity to address these impacts and investigate its fingerprint on the landscape over 2000 years. To approach this, representative sediment samples were isolated and analyzed from two sediment cores (C1, C2), an excavated trench (W), and a sample of ancient harbour construction material (aeolianite sandstone and hydraulic concrete; COF). Geochemical (Itrax μXRF, magnetic susceptibility) and foraminifera analyses were conducted and results from both methods were statistically grouped into significantly similar clusters. Results demonstrated the increased presence of aeolianite-associated elemental contributions only after the construction of Caesarea as well as in particularly high concentrations following previously proposed tsunami events, during which shallower and deeper materials would have been transported and redeposited. The foraminifera data shows the appearance and eventual abundance dominance of Pararotalia calcariformata as an indicator of coastal hardening. Results suggest that they are an especially well-suited species to demonstrate changing environmental conditions existing today. In previous studies, this species was mistakenly presented as a recent Lessepsian arrival from the Red Sea, when in fact it has had a long history as an epiphyte living on hardgrounds in the Mediterranean and co-existencing with humans and their harbour-building habits. Specimens of P. calcariformata, therefore, are useful indicators for the timing of harbour construction at Caesarea and may be used as rapid and cost-effective biostratigraphic indicators on sandy nearshore coastline in future geoarchaeological studies. This has implications for future studies along the Israeli coast, including both paleoenvironmental and modern ecological assessments.

1. Introduction

Ancient harbour sediments and stratigraphy are often studied because they contain evidence of past environmental change including climate, sea-level, and anthropogenic activity (Blackman, 1982a, 1982b; Kamoun et al., 2019, 2020, 2021; Marriner and Morhange, 2007; Reinhardt et al., 1994; Riddick et al., 2021; Riddick et al., 2022a, 2022b; Salomon et al., 2016). The analysis and interpretation of environmental proxies (e.g., microfossils, geochemistry, lithology, etc.) can be more straightforward in cases of shoreline progradation, where relative sea-level changes, siltation, and/or high input of river sediments have resulted in landlocked marine structures (i.e., within lagoons or estuaries). Sediments in these cases often record transitions from marine to more brackish/freshwater conditions associated with construction of harbour structures and/or natural barriers that are identifiable through changes in microfossil assemblages, sediment grain size and geochemistry, and other environmental indicators (Amato et al., 2020; Finkler et al., 2018; Kamoun et al., 2022; Pint et al., 2015; Stock et al., 2013, 2016).

The environmental evolution (i.e., site formation) of ancient harbour sites on high-energy, sandy coasts is more challenging to assess. Sediments from within a harbour basin can record geoarchaeological information (e.g., ancient harbour parasequences, changes in microfossil assemblages, archaeological material, etc.; Marriner and Morhange, 2006; Reinhardt et al., 1994; Riddick et al., 2021; Riddick et al., 2022a, 2022b); however, correlating stratigraphy in a harbour region can often be hindered by sediment reworking with waves and storms and by the absence of significant lithological changes in the sandy stratigraphy, with the exception of tsunamis or other large storm events (Goodman-Tchernov et al., 2009). The emplacement of ancient harbours (i.e., artificial hard substrates) on naturally soft-bottomed, sandy shorelines, significantly alters the local seascape resulting in sediment erosion and accumulation as well as the formation of a hard and stable substrate (Leys and Mulligan, 2011).

Past research on ancient harbour sediments (e.g., Marriner et al., 2005; Reinhardt et al., 1994; Salomon et al., 2016) has focused on analysis of harbour muds, recognizable by their muddy-appearance (finer particle size distribution; ‘muds’; Hohlfelder, 2000), higher organic content, and increased concentrations of artifacts. In those studies, various bioindicator proxies, in particular gastropods, molluscs, ostracods, and foraminifera, were used to recognize harbour stratigraphy and related changing conditions connected to construction, destruction, and/or functionality (Kamoun et al., 2019, 2020, 2021; Marriner et al., 2005; Reinhardt and Raban, 1999). Amongst marine biomarkers, benthic foraminifera are especially popular as environmental proxies due to their known ecological preferences and tolerances, their rapid response to environmental change, and their durability in the sediment record over time (Holbourn et al., 2013; Murray, 2014). Generally, research to date on ancient harbour assemblage changes were linked to the increased presence of fine-grainedsediment preferring species (e.g., Bolivinids) as well as shifting relative abundances of the more dominant brackish Ammonia species (Goodman et al., 2009; Kamoun et al., 2022; Marriner et al., 2005; Reinhardt et al., 1994; Reinhardt and Raban, 1999). This agrees with the more general understanding that substrate is a major controlling factor in foraminifera assemblages (Langer, 1988, 1993). We hypothesize here that while the harbour muds introduce new conditions for a changing benthic foraminifera assemblage, so too can the increased presence of hard materials related to harbour construction and coastal development. These hard surfaces are especially influential on attached, epiphytic taxa. These taxa, therefore, will record a response to the introduction of artificial hard substrates in the sandy, high-energy settings seaward and beyond the protected environments of the harbour, and can act as biostratigraphic indicators of pre- and post- harbour sediments, a concept that has not previously been tested or applied.

Previously collected samples from an excavated trench area (W; Reinhardt et al., 2006), two sediment cores (C1, C2; Goodman-Tchernov et al., 2009), and a piece of harbour mole material retrieved during underwater excavations in 1999 (COF; Reinhardt et al., 2001) were included in this study (Fig. 1). Seven samples (5-cm intervals) were available from W (− 11.4 to − 13.4 m below sea level (mbsl), ~0.60 km from the coast; Reinhardt et al., 2006). Nineteen samples (1-cm intervals) from the upper 126 cm were available from C1 (233 cm in length, 15.5 mbsl, ~0.82 km from the coast) and 14 samples (1-cm intervals) were available from C2 (174 cm in length, 20.3 mbsl, ~1.25 km from the coast; Goodman-Tchernov et al., 2009). Radiocarbon and/or pottery dating methods were previously conducted on W, C1, and C2 samples. See Goodman-Tchernov et al. (2009) and Reinhardt et al. (2006) for further details on dating methods used. Geochemical ((μXRF, magnetic susceptibility) and foraminifera methods were applied here. The use of benthic foraminifera as biostratigraphic indicators to help correlate sediments in archaeological contexts is still a developing area of research (McGowran, 2009). The application of benthic foraminifera in this manner will be useful for future geoarchaeological studies as a rapid and cost-effective method for correlating sediments across an ancient harbour site, especially in high energy sandy shoreface settings. Results also have implications for understanding sediment transport in and around coastal structures, as well as for modern studies involving the monitoring and/or predicting of ecological changes in response to coastal anthropogenic activity.

2. Background

2.1. Regional geology and geochemistry

The Israeli Mediterranean coastline (Fig. 1) is mostly characterized by unconsolidated sands and Pleistocene aeolian sandstone ridges (‘kurkar’). These thick calcareous-cemented sand beds accumulated cyclically between thin layers of iron-rich paleosols (‘hamra’) and currently run parallel to the coast, both on and offshore (Almagor et al., 2000; Ronen, 2018). The southern two thirds of the coastline are characterized by sandy beaches (Emery and Neev, 1960). The tidal range is relatively small along the coast (0.4 during spring tides, 0.15 m during neap tides; Golik and Rosen, 1999). Offshore sediments are transported through two different types of nearshore currents: an inner edge of the general offshore current (which moves northwards, counterclockwise along the eastern end of the Mediterranean; Fig. 1), and a wave-induced longshore current (Emery and Neev, 1960; Goldsmith and Golik, 1980; Klein et al., 2007; Schattner et al., 2015). The largest waves in this region generally approach the coast from a WNW direction, which results in a longshore current to the northeast along the curved southern shoreline (Fig. 1). Where these waves approach parallel or at an angle opposite to that of the southern coast (e.g., some areas towards the northern coastline of Israel), a small, southward longshore current is produced (Emery and Neev, 1960; Goldsmith and Golik, 1980; Zviely et al., 2007). Located towards the northern extent of the Nile Littoral Cell, offshore sediments near Caesarea are predominantly transported from the south through this wave-induced longshore current (Emery and Neev, 1960; Goldsmith and Golik, 1980; Golik, 1993, 1997; Katz and Crouvi, 2018; Schattner et al., 2015; Zviely et al., 2007). Prior to the construction of the Aswan Dam in the 1960s, approximately 100,000 m3/yr of clastic sediments reach the coasts of Caesarea, largely sourced from Central Africa and the Ethiopian Highlands (Nir, 1984). These sediments are dominated by silica (quartz), alumina, and trivalent iron oxides (e.g., aluminosilicates) with minor amounts of heavy minerals (Goldsmith et al., 2001; Inman and Jenkins, 1984; Nir, 1984). The majority of heavy minerals include hornblende, augite, and epidotes, as well as minor amounts of resistant (e.g., zircon, tourmaline, rutile) and metamorphic minerals (e.g., sillimanite, staurolite, kyanite; Stanley, 1989). Local sources (i.e., eroded kurkar, onshore sediments, marine productivity) contribute some calcareous sediment to the nearshore environment (Goldsmith et al., 2001; Inman and Jenkins, 1984; Nir, 1984; see Supplementary Data 1 for more details on dominant minerals, compositions, and sources). Sand-sized sediment extends 3–5 km from the shore to water depths of ~25 m, while increasing amounts of silt and clay (mainly smectite, with minor kaolinite and illite) are found further offshore in slightly deeper water (30–50 m depths; Almagor et al., 2000; Emery and Neev, 1960; Nir, 1984; Sandler and Herut, 2000). The siliclastic sands, which characterize most of the nearshore, transition into more carbonate-rich sediments with higher instances of rocky substrates north of Haifa Bay (Almagor et al., 2000; Avnaim-Katav et al., 2015; Hyams-Kaphzan et al., 2014; Nir, 1984).

2.2. Historical and geological background on installations at Caesarea

The historical site of Caesarea Maritima is located ~40 km south of Haifa, on the Israeli Mediterranean coast (34◦53.5′E 32◦30.5′N). Over six decades of research have provided details on the construction and deterioration of its harbour, also referred to as Sebastos, the largest artificial open-sea Mediterranean harbour of its time (Brandon, 2008; Hohlfelder et al., 2007). The harbour was constructed between 21 and 10 BCE using local kurkar and imported volcanic material (Vola et al., 2011; Votruba, 2007). Local kurkar is characterized by well-sorted quartz with calcite and minor amounts of feldspar, biotite, heavy minerals (e.g., hornblende, augite, zircon, rutile, tourmaline, magnetite, garnet, etc.), and allochems (Wasserman, 2021). Volcanic material has been used in concrete by the Romans since the 2nd century BCE (Oleson, 1988), often sourced from the Bay of Naples Neopolitan Yellow Tuff (NYT) deposits. Pozzolanic tuff-ash from this region was used in hydraulic concrete to form the breakwaters and foundations for harbour moles at Sebastos (Vola et al., 2011; Votruba, 2007). The mixture of lime, pozzolana, and aggregate provided a strong concrete that could set underwater. At Caesarea, the dominant coarse aggregates in the hydraulic concrete are kurkar sandstone and limestone (4 mm–20 cm in size; Vola et al., 2011). The mortar contains high proportions of pozzolanic material (yellow brown tuff ash/aggregates, lava fragments) with dominant minerals identified as sanidine, clinopyroxene, analcime, and phillipsite. The cementitious binding matrix contains similar material (calcite, tobermorite, ettringite, Calcium–Aluminum–Silic ate–Hydrate) and was likely produced by the reaction between powdered pozzolanic material, lime, and seawater. Non-pozzolanic portions include white lime clasts, kurkar sandstone aggregates, ceramics, and wood fragments, with dominant minerals identified as tobermorite, quartz, illite, anthophyllite, ettringite, halite, bassanite, and sjogrenite (Vola et al., 2011; Supplementary Data 1).

The chronology of Sebastos has been well-studied, with detailed research into the timing of deterioration and harbour use throughout antiquity (Boyce et al., 2009; Galili et al., 2021; Goodman-Tchernov and Austin, 2015; Hohlfelder, 2000; Raban, 1992, 1996; Reinhardt et al., 2006; Reinhardt and Raban, 1999). The location of Sebastos on a highenergy, mostly sandy coastline, as well as the previously established chronology of harbour construction, makes this an ideal site to assess the use of benthic foraminifera as biostratigraphic indicators of anthropogenic structure emplacement. The distribution of benthic foraminifera along the Israeli coast has been well-documented, providing a strong basis for interpreting trends within sediment samples offshore of Caesarea.

2.3. Benthic foraminifera of the Israeli Mediterranean coastline

Introduction

Studies of both living and dead benthic foraminifera assemblages along the Israeli coast of the Mediterranean Sea indicate that substrate type (often linked to bathymetry), food availability, and seasonality are the main factors controlling the distribution of species (Arieli et al., 2011; Avnaim-Katav et al., 2013, 2015, 2016a, 2020, 2021; HyamsKaphzan et al., 2008, 2009, 2014). Certain taxa such as Ammonia parkinsoniana and Buccella spp. are highly abundant in the shallow (3–20 m), sandy nearshore settings. Others including Ammonia inflata, Ammonia tepida, Elphidium spp., Porosononion spp., and miliolids are often observed in slightly deeper (20–40 m), silty to clayey environments further offshore on the inner Israeli shelf (Avnaim-Katav et al., 2013, 2015, 2016a, 2016b, 2017, 2020, 2021; Hyams-Kaphzan et al., 2008, 2009, 2014). Epiphytic taxa, which live on roots, stems, and leaves of plants (Langer, 1993; Langer et al., 1998), are highly associated with the micro- and macroalgal-covered hard substrates along the Israeli Mediterranean coast, especially the carbonate-rich rocky settings along the northern coast (Arieli et al., 2011; Avnaim-Katav et al., 2013, 2015, 2021; Hyams-Kaphzan et al., 2008, 2014). Coralline red algae (e.g., Galaxuara rugosa and Jania rubens) are highly abundant along the Israeli coast, along with other types of red (e.g., Centroceras sp., Ceramium sp., Bangia sp., Halopteris scoparia, Laurencia sp., Neosiphonia sp., and Polysiphonia sp.), brown (e.g., Dictyora sp., and Ectocarpus sp.), and green algae (Codium sp. and Ulva sp.; Arieli et al., 2011; Bresler and Yanko, 1995a, 1995b; Emery and Neev, 1960; Hyams-Kaphzan et al., 2014; Schmidt et al., 2015). Some of the most common epiphytic foraminifera taxa observed here include Amphistegina lobifera, Lachlanella spp., Heterostegina depressa, Pararotalia calcariformata, Rosalina globularis, Textularia agglutinans, and Tretomphalus bulloides, (Arieli et al., 2011; Hyams-Kaphzan et al., 2014). Many of these larger, symbiont bearing foraminifera are widely assumed to be more recently introduced Lessepsian species, a term used to describe Red Sea/Indian Ocean tropical species that have arrived after the construction of the Suez Canal (1869 CE). While some have been linked genetically and morphologically with their Red Sea communities, others, such as P. calcariformata (Schmidt et al., 2015; Stulpinaite et al., 2020) still have not

2.3.1. Pararotalia calcariformata

Specimens of P. calcariformata McCulloch, 1977 were originally identified as P. spinigera (Le Calvez, 1949) on the Israeli coast, in particular within dated, stratigraphically discreet underwater archaeological excavations and geological collections (e.g., in Reinhardt et al. (1994, 2003), Reinhardt and Raban (1999)). Schmidt et al. (2015)’s initial error occurred when they mistook the date of the first publication that reported them on this coastline for the timing of their first observation (see reference to Reinhardt et al., 1994 in introduction of Schmidt et al., 2015). In fact, the P. calcariformata in that study were firmly positioned in sediments dating to at least 1500 years ago. P. calcariformata is a well-documented epiphyte, found in highest abundances near hard substrates (up to 96% in shallow rocky habitats) of the Israeli coast (Hyams-Kaphzan et al., 2014; Reinhardt et al., 2003), usually living on calcareous algae and other seaweeds (e.g., Jania rubens, Halimeda, Sargassum, Cystoseira; Arieli et al., 2011; Bresler and Yanko, 1995a, 1995b; Emery and Neev, 1960; Schmidt et al., 2015, 2018). It is observed less frequently (up to 20% relative abundances) in shallow, soft-bottomed, sandy sediments (Avnaim-Katav et al., 2017, 2020; Hyams-Kaphzan et al., 2008, 2009). Recent work on this species explores its microalgal symbionts (Schmidt et al., 2015, 2018) and its high heat tolerance (Schmidt et al., 2016; Titelboim et al., 2016, 2017). These studies predict that warming sea temperatures will play a role in expanding populations of P. calcariformata along the Mediterranean.

4. Results

4.1 Core lithology and chronology

W is described in Reinhardt et al. (2006), while C1 and C2 are described in Goodman-Tchernov et al. (2009). W (~2 m of excavated sediment) contains two main shell layers: (i) a poorly sorted mix of Glycymeris spp. and pebbles from ~107–165 cm, with convex-up oriented fragments in the top portion, and (ii) a heterogeneous layer of shell fragments, ship ballast, and pottery shards from ~39–59 cm. The intervening units consist of massive, homogeneous, medium-grained sand with isolated articulated and fragmented bivalve shells and/or pebbles. The upper ~0–39 cm also contains thin layers of shells and pebbles (Fig. 2). The upper 126 cm of C1 contains two shell layers: (i) a poorly sorted mix of Glycymeris spp. and pebbles, with fragments of worn pottery from 85 to 94 cm, and (ii) poorly sorted, convex-up oriented Glycymeris spp. and pebbles from 28 to 42 cm. The intervening units are massive, tan/grey, fine-grained sand, some with isolated bivalves and/or pebbles (Fig. 2). C2 (174 cm) similarly contains two shell layers: (i) framework supported, convex-up oriented Glycymeris spp. fragments from 132 to 138 cm, and (ii) convex-up oriented Glycymeris spp. fragments from 29 to 43 cm. The intervening units are massive, tan/ Gy, fine-grained sand with some silt and isolated bivalves.

The chronology of W, C1, and C2 has been previously described (Goodman-Tchernov et al., 2009; Reinhardt et al., 2006), and units have been correlated to age ranges (radiocarbon and pottery; Table 1) and identified events (i.e., tsunami deposits; Fig. 2). W, C1, and C2 were found to capture similar event layers dating to ~1492–100 BCE (preharbour), 92 BCE–308 CE (containing the 115 CE Roman tsunami event), 238 BCE–329 CE, 400–800 CE (containing the 551/749 CE Late Byzantine/Early Islamic tsunami events), and 800 CE–present (Table 1, Fig. 2).

4.2. Geochemical results

Elemental (μXRF) results are shown in Fig. 3 and Supplementary Data 2. Average counts of Zr increase upcore in each sampling area, with uppermost values ~2–3 times higher than those at the base (~700–1000 compared to 200–400; Fig. 3, Supplementary Data 2). Ca is highly variable throughout all sampling areas, with some peaks up to 1.7× higher (~300,000) in shell layers than in sandy samples. Counts of Si remain relatively high (~17,000) throughout time, with some decreases up to 1.5–2.5× lower in shell layers. Average Ti values are variable through time (~6000) with some spikes up to 2× higher at the top and bottom of C1 and surrounding the bottom shell layer of C2. Fe follows similar trends to Ti, with values ~2× higher near the top and bottom of C1 and the darker sandy sediments of C2 (161–123 cm) compared to the intervening sandy samples (counts of ~6000–7000). Counts of Sr remain quite constant throughout all sampling areas over time (~2000), with a slight increasing trend in the upper portions of C1 and C2 (values up to ~1.3×; Fig. 3, Supplementary Data 2).

Ratio results of Zr + Ti/Ca and Zr + Ti/Si are variable throughout time in W (values 0.02–0.04 and 0.20–0.34) and C2 (0.03–0.08 and 0.4–1.4), especially within tsunami event layers, though results show no clear increasing/decreasing trends over time. In C1, these ratios show a distinct increasing trend through the upper half of the core (Zr + Ti/Ca: from 0.02 up to 0.06; Zr + Ti/Si: 0.3 up to 0.7). Sr/Ca values remain relatively consistent in all coring areas (~0.10), with minor variation surrounding shell layers (Fig. 3, Supplementary Data 2).

Sample COF shows distinct variation in elemental composition between kurkar and hydraulic concrete (Fig. 4). On average, counts of Zr and Ti are over 10× higher in the hydraulic concrete than the kurkar. Counts of Fe are also higher in the hydraulic concrete by a factor of ~8. Ca shows the opposite trend, with counts 5× higher in the kurkar than the hydraulic concrete. Counts of Si were variable throughout both materials but were slightly higher in the hydraulic concrete. Sr peaked in the kurkar and decreased moving into the hydraulic concrete, with some variability associated with the aggregate material (Fig. 4). Ratio results for Zr + Ti/Ca are ~94× higher in the hydraulic concrete than in the kurkar, while Zr + Ti/Si values are almost 2× higher. Sr/Ca are ~4× higher in the hydraulic concrete than in the kurkar (Fig. 4).

The cluster analysis of W, C1, C2, and COF results displayed seven superclusters (SC1–SC7; Fig. 5). SC1 and SC2 are highly similar, though SC1 contains relatively higher counts of Si and lower counts of Ti and Fe than SC2. SC2 appears more frequently in samples from the upper halves of the cores, while SC1 appears more frequently in deeper and older contexts (Fig. 5). SC3 and SC4 appear only in the ash-rich portion of COF. SC5 is highly similar to SC1, with some peaks in Zr and Sr compared to SC1, appears mainly in the sandy units of cores, and reflects the general sedimentary background of the coast. SC6 contains very few samples and is analogous to SC5. SC7 is characterized by relatively high counts of Ca and Si and is predominantly associated with the kurkar portion of COF, with some samples from tsunami layers of W and C1, and with the uppermost sand layers of C2 (Fig. 5).

The magnetic susceptibility of sediments remains relatively low throughout all samples (Table 2). Aside from a peak (27.8 × 10− 6 SI) at the top of C1, values range between 5.2 and 10.4 × 10− 6 SI in C1, 8.9–13.5 × 10− 6 SI in C2, and 2.6–7.1 × 10− 6 SI in W, with no distinct trends over time (Table 2).

4.3. Foraminifera results

Thirteen statistically significant foraminifera taxa were identified across W, C1, and C2, and the cluster analysis revealed four significant (au >95%) assemblages (A1, A2, A3, A4; Figs. 6 and 7, Supplementary Data 3). The NMDS showed that the four assemblages overlapped, especially A2, A3, and A4, suggesting that samples within these assemblages were quite similar despite grouping distinctly (Fig. 6). A1 contains only samples from the tops of W and C1. This assemblage is dominated by A. parkinsoniana (~3–21%), P. calcariformata (~43–74%), and miliolids (~13–20%; Fig. 7; Supplementary Data 3). A2 contains samples from the sand and lower shell layers of W, as well as the lower shell layer of C2. Assemblage A2 is dominated by A. parkinsoniana (~46–70%), Porosononion spp. (~0–19%), and miliolids (~12–22%). Assemblage A3 contains samples from the top and middle shell layers of C1, as well as the top sand, middle sand and shell layers of C2. Dominant specimens within this assemblage include A. parkinsoniana (~4–23%), P. calcariformata (~0–19%), Porosononion spp. (~2–11%), and miliolids (~42–69%). A4 contains samples from the middle sand layers of C1, as well as the middle sand, and bottom shell and sand layers of C2 (Fig. 7). This assemblage is dominated by A. parkinsoniana (~20–44%), P. calcariformata (~0–21%), Porosononion spp. (~1–17%), miliolids (~21–46%), and planktonic foraminifera (~0–15%; Fig. 7; Supplementary Data 3).

Increasing abundances of P. calcariformata (Supplementary Data 4) over time were observed in all three sampling locations. In W, this species was relatively abundant (0.38–51.74%) and was observed in all samples except for 150–155 cm. Pararotalia calcariformata was observed at highest abundances (0.91–73.68%) in the top 0–71 cm of C1, and at lowest abundances (6.25–20.79%) in the top 0–42 cm of C2. This species was also observed at relatively low abundances towards the bottom of C2 (1.19% at 126–127 cm and 0.71% at 131–137 cm).

5. Discussion

5.1. Pre-harbour nearshore sediment composition and distribution

Prior to the construction of Sebastos, the shoreline at Caesarea was characterized by a soft-bottomed, unconsolidated sandy beach overlying regional kurkar ridges (Fig. 8; Almagor et al., 2000; Reinhardt et al., 1994; Ronen, 2018). This is reflected in both foraminifera and geochemistry results in C2 and the lower two thirds of C1 and W (Figs. 3, 7). Biofacies A2, A3, and A4 (pre-harbour), characterized by relatively higher proportions of A. parkinsoniana, miliolids, and Porsononion spp., are consistent with Reinhardt et al. (1994)’s pre-harbour foraminiferal faunal results (Fig. 7). These taxa are typically associated with shallow and mid-depth (3–20 m, and 20–40 m) Nilotic sands and silty–clayey sediments of the Israeli inner shelf (Avnaim-Katav et al., 2013, 2015, 2016b, 2017, 2019, 2020, 2021; Hyams-Kaphzan et al., 2008, 2009, 2014). The minor presence of P. calcariformata at the bottom of C2 and in pre-harbour sediments is associated with the coarse shell unit of the Santorini tsunami (Goodman-Tchernov et al., 2009). This event transported shallow marine sediment offshore including the epiphytic P. calcariformata, likely from the kurkar hard grounds (Reinhardt et al., 2003).

The relative consistency in average counts of Ca, Si, Ti, and Fe through time within the sandy units of each of the three sampling areas suggests that there is virtually no difference in abundance of these elements in pre-and post-harbour sediments (Fig. 3; Supplementary Data 2). This reflects the pre-harbour (and post-harbour) regional geology (local carbonate-rich kurkar), marine productivity (e.g., shells), and Nile sediment sources (aluminosilicate minerals within the shoreline’s sands, silts, and clays, as well as the minor amounts of heavy minerals; Supplementary Data 1 and 2). In pre-harbour sediments, slight variations in counts for Ca, Si, Ti, and Fe (increases or decreases in average counts by factors of ~1.1–1.8) predominantly surround the Santorini event (Fig. 3). This is expected, as high-energy events typically result in abnormal deposition (e.g., shell material, rip-up clasts, archaeological material, beach-derived pebbles) that would be reflected in geochemical results (Goodman-Tchernov et al., 2009; Kamoun et al., 2021).

The cluster analysis of elemental data shows very slight variation in sediment composition based on sample location, especially between W and C2 (Fig. 5), which could be the result of natural nearshore sediment transport patterns (Almagor et al., 2000; Emery and Neev, 1960; Quick, 1991). Onshore-offshore sediment transport is mainly wind-driven and is controlled by several forces related to incoming waves, sediment size, and beach slope (Quick, 1991). During summer months on the Israeli coast, relatively calm northwesterly winds generate waves and currents that cause sands to move shoreward (Almagor et al., 2000; Emery and Neev, 1960; Quick, 1991). During winter months, strong southwesterly storm winds result in offshore sand transport. Since waves break at an angle to the Israeli shoreline, onshore-offshore sediment movement occurs in a slightly oblique direction, with net transport northwards (Almagor et al., 2000; Emery and Neev, 1960). Because the amount of sediment carried through longshore currents decreases northward, and beach accretion along the coasts largely does not take place, researchers have concluded that sediment must be lost (e.g., moved seawards or blown landwards) along the way (Almagor et al., 2000; Emery and Neev, 1960). Through a study on sand balance, Almagor et al. (2000) estimated that roughly 450,000 m2 /year of sediment is lost to seaward escape between Gaza and Haifa. Sands are actively deposited within a gently sloping (0.5–0.8◦) nearshore zone extending 3–5 km offshore (~40 m water depth), near the easternmost drowned kurkar ridge (Almagor et al., 2000). Sands that escape past this point are mixed with increasing amounts of silts and clays that accumulate on a relatively flat seabed (Almagor et al., 2000; Nir, 1984; Sandler and Herut, 2000). All sampled areas in this study are within this zone of active sedimentation, though each site was sampled at different depths and distances from shore, so we would expect to see some natural variation in composition.

5.2. Post-harbour nearshore sediment composition and distribution

5.2.1. Geochemical indicators of harbour deterioration

The chemofacies results reflect coastal development, mainly through SC1, SC2, and SC7. SC1 is a coarser grain version of sediments that cluster with SC2. SC1 replaces SC2 in the upper portion of all three cores. The reduction in clays (indicated by Ti) and increase in silica within this shift in chemofacies suggests slight grain coarsening over time, while the increase in Ba indicates an increase in productivity. This slight shift over time may represent natural changes in sediment sources (e.g., variations in White and Blue Nile sediments, terrestrial inputs, etc.) and/or anthropogenic influence (Kalman et al., 2022). SC7, which relates to the kurkar component of sediments (Figs. 4 and 5), appears much more frequently post-harbour and with tsunami influence. Kurkar was heavily used in the construction of the harbour (Vola et al., 2011; Votruba, 2007), and tsunamis transported and deposited this material further offshore. The slight presence of SC7 in the Santorini event layer (C1, Fig. 5) reflects this process occurring pre-harbour, with natural kurkar deposits along the coast.

Heavy minerals including zircon and rutile exist in Israeli sands in minor abundances (Lin et al., 1974; Pomerancblum, 1966; Stanley, 1989), as demonstrated by the presence of Zr (~300) and Ti (~5000) throughout the pre-harbour sediment samples. These minerals come from several sources including Nile sediments, local onshore terrains, aeolian dust, and reworked sedimentary bedrock (Supplementary Data 1). On the Israeli coast and other high-energy, sandy shorelines, heavy minerals become naturally concentrated due to mechanical sorting (Stanley, 1989). Through waves and currents, denser mineral grains typically settle out of suspension and accumulate at the bottom of the swash zone while lighter grains are carried back towards shore to the wave zone (Dinis and Soares, 2007; Hou et al., 2017). Abundances along the Israeli coast are still relatively low (~0.1–0.5%; Lin et al., 1974). Differences along the coast due to varying local sources of sediment (e. g., nearby wadis/rivers) are minor, and any significant changes in heavy mineral abundances would require vast amounts of sand inputs (Boenigk and Neber, 2005). The increase in Zr + Ti/Ca and Zr + Ti/Si values from pre- to post-harbour sediments (by factors of 3 and 2.3, respectively), and the observed increasing trend within post-harbour sediments is therefore not likely to be caused by natural sources and is most likely related to harbour deterioration. Although Zr was not reported in Vola et al. (2011)’s bulk chemical and petrographic analysis of Sebastos concrete and TiO2 was only a minor component of the mortar (0.2–0.3%), we observed distinctly higher values of Zr and Ti throughout the hydraulic concrete portion of COF (avg Zr + Ti/Ca: 0.187; avg. Zr + Ti/Si: 2.02) compared to the kurkar portion (avg Zr + Ti/Ca: 0.002; avg. Zr + Ti/Si: 1.27). This suggests the presence of trace amounts of (or mineral impurities including) Zr and Ti within the aggregate material and the fine-grained matrix of the concrete. Our results suggest that the foreign volcanic material contains a much larger proportion of heavy minerals compared to local kurkar sources of sediment.

Magnetic susceptibility results are comparable to previous studies of Caesarea. Boyce et al. (2004, 2009) found a range of 0.1 to 8.7 × 10− 5 SI for harbour bottom sands and muds, which is similar to most sediments in this study (2.6 to 13.5 × 10− 5 SI; Table 2). The relatively extreme value observed at the top of C1 (27.8 × 10− 5 SI) more closely aligns with values of pozzolana (22.7 to 175.2 × 10− 6 SI; Boyce et al., 2004) than the quartz sands and harbour muds. The presence of eroded hamra material (κ = 88.0 × 10− 5 SI; Boyce et al., 2004), eroded igneous or metamorphic ballast stones (κ ≥90 to >200 × 10− 5 SI; Boyce et al., 2009) or eroded clay fragments (κ = 133.7 × 10− 5 SI; Boyce et al., 2004) could also be influencing the higher value at the top of C1. Any of these sources could indicate increased presence of harbour material in recent offshore sediments (Fig. 8). Additional sediment samples, especially throughout the top portion of W and C1 would help to confirm the observed trends in magnetic susceptibility.

Observable changes in heavy minerals following harbour construction occur within sediments between the Santorini event (1630–1550 BCE) and the Late Byzantine/Early Islamic tsunami events (551/749 CE); however, correlating a more precise estimated depth for the timing of harbour construction remains a challenge solely with the XRF results (Fig. 3). The benthic foraminifera results, however, can be used to further refine these estimates.

5.2.2. Epiphytic foraminifera as biostratigraphic indicators of artificial substrate chang

lations is evident in A1, at the tops of W and C1 (Fig. 7). This assemblage contains distinctly higher abundances of P. calcariformata (Fig. 9; Supplementary Data 4), a common epiphytic species usually found in association with calcareous algae in rocky areas of the Israeli inner shelf (Arieli et al., 2011; Bresler and Yanko, 1995a, 1995b; Emery and Neev, 1960; Hyams-Kaphzan et al., 2014; Reinhardt et al., 2003; Schmidt et al., 2015, 2018). As harbour structures progressively over time, increasing amounts of cryptic spaces would have formed, providing increasing amounts of surface area for algal or seagrass growth. Ratio values for Sr/Ca do not seem to vary significantly over time, suggesting a continuous presence of aragonitic organisms (shells, calcareous algae, etc.). In C1, values slightly increase over time following a drop during the Late Byzantine tsunami event (Fig. 3) which may be related to an increase in calcareous algal growth on harbour ruins. Increased sample resolution would help to confirm this trend. Hard substrates (i.e., submerged harbour structures) with algal growth are optimal settings for P. calcariformata, and increased populations of this species after harbour construction are recorded in all three sampling areas. After death, these specimens would have detached from the algalcovered harbour and been transported to the nearby sediments by onshore-offshore transport mechanisms discussed above (Section 5.1), especially by strong storm waves during winter months (Fig. 8; Almagor et al., 2000; Quick, 1991). Higher abundances are recorded in deposits close to the site (i.e., W and C1), though their presence is still observed 800 m from the harbour structures (C2; Fig. 7).

Other epiphytic species are present in low abundances throughout the sampling areas (Fig. 9) but do not show significant trends over time, likely due to their preferred habitats. Textularia bocki and T. bulloides are more often associated with the northern coast of Israel beyond the Nile littoral cell; T. bocki is usually found in deeper (30–100 m), silty-clayey sediments (Avnaim-Katav et al., 2013, 2015, 2020, 2021), while T. bulloides has been observed in shallow rocky areas surrounding Haifa (Arieli et al., 2011; Hyams-Kaphzan et al., 2014). These foraminifera results demonstrate the importance of understanding the distribution 800 m from the harbour structures (C2; Fig. 7).

and habitat preferences for the taxa of a specific region when considering using epiphytic species as indicators of substrate changes. The benthic foraminifera result here, especially P. calcariformata, provide information to help further correlate the timing of harbour construction within C1 and C2 (Fig. 7). Results also confirm that P. calcariformata is not a recent invasive species as previously thought (Schmidt et al., 2015; Stulpinaite et al., 2020). In all three cores, P. calcariformata was observed in sediments follow construction of Sebastos harbour, and in C2, specimens were observed in two samples dating to the Santorini event bed (1630–1550 BCE; Fig. 7; Supplementary Data 3). This supports Reinhardt et al. (1994)’s observations of this species in historical sediments, as well as Stulpinaite et al. (2020)’s verdict that this species is native to the Mediterranean, and suggests that it has been living on the eastern Mediterranean coast since around the Late Bronze Age. The results here indicate that substrate conditions are an important habitat control on P. calcariformata. This has not been adequately considered in recent studies that explore the distribution of this species. Schmidt et al. (2015) briefly mention that there is some substrate control on this species, though estimations of range expansions have been based on solar radiance, turbidity, and temperature even though samples in the studies were all associated with hard substrates (Schmidt et al., 2015, 2016, 2018; Titelboim et al., 2016, 2017). Similarly, Yanko et al. (1994) discussed sea temperature as a key factor influencing the higher abundance of this species in proximity to the site of Hadera; however, they failed to consider the presence of extensive hard grounds with algal coverage at the power station. The results here suggest that nearby substrates, including artificial structures such as harbour or pilings, should be considered in future research involving the distribution of benthic foraminifera along the Mediterranean.

5.3. Implications for sediment transport and site formation

Based on the distribution pattern of P. calcariformata observed here, alternative applications of epiphytic foraminifera along high energy sandy shoreface settings could include long-term studies on sediment dynamics (e.g., tracking sediment transport in and around coastal structures, the extent of onshore-offshore sand movement, tracking the extent of the storm weather wave base over time, etc.). Understanding sediment dynamics is important for coast engineering projects (Leys and Mulligan, 2011). Fluorescent tracers are often used to assess onshoreoffshore sediment transport and sediment accumulation patterns around marinas; however, these methods only provide data spanning several months (Klein et al., 2007). Because the main source of P. calcariformata in high energy sandy shoreface settings is the submerged surface of harbour structures (anthropogenic hard grounds), these microfossils can provide long-term data on onshore-offshore transport trends, sediment accumulation patterns around the harbour itself, and on longshore transport patterns along the coast. This could enhance studies using fluorescent tracers as it provides more long-term information.

Sediment reworking (vertical movement) during storms and tsunamis plays a major role in the stratigraphic distribution of P. calcariformata. As discussed in Reinhardt and Raban (2016), the sands within the active sediment layer are regularly reworked. Storms and tsunami waves often cause scour and erosion of the seabed as well as removal of fine sand particles from around larger, heavier, rubble material. This results in vertical transport of the rubble material downwards, producing an “armoured” layer that resists further erosion (Reinhardt and Raban, 2016). Foraminifera and larger sand particles within the active sediment layer would be reworked through this winnowing action as well, with larger storms having a greater effect on transport, especially closer to shore. This mechanism of sediment reworking would occur offshore up to the storm weather wave base, though to a lesser extent. Significant abundances of P. calcariformata would likely not be transported much further offshore and therefore provide recognition of the storm wave base through time. Our three cores show this trend with P. calcariformata, found at ~0–30 cm at 20 m water depth (C2, ~0–60 cm at 15 m (C1), and ~ 0–150 cm at 10 m (W). This shows that shallow marine sands are being transported at least ~2 km offshore with larger storms. The presence/absence of P. calcariformata provides an efficient low-cost method for determining pre- and post-harbour sediment which can be difficult to identify in these sandy high-energy settings, especially if the sands contain no material culture (e.g., pottery).

6. Conclusions

This study shows that anthropogenically altered coastlines, in particular hard coastal structures, leave a fingerprint on their environment not only through changed elemental composition but also biomarkers such as epiphytic foraminifera. These changes are present and recognizable in the ancient harbour context at Caesarea Maritima. There, an excavated trench area (W), two sediment cores (C1, C2), and a piece of harbour material (COF) were analyzed through elemental (μXRF, magnetic susceptibility) and/or foraminifera analyses. Heavy mineral proxies (Zr + Ti/Ca, Zr + Ti/Si, magnetic susceptibility) indicate that particulate matter offshore, originating as part of or due to the harbour structures have increased since the construction of the harbour ~2000 years ago. Benthic foraminifera assemblages A3, and A4 reflect the shallow and mid-depth (3–40 m) sandy to sandy silt substrates that characterized much of the nearshore Israeli coast prior to harbour construction. Post-construction assemblages (e.g., A1, A2) include increasing abundances of epiphytic species, especially P. calcariformata. This species was successfully used as a biostratigraphic indicator for the timing of harbour construction as it is present in significant abundances only after the harbour and city are established around 2000 years ago. Pararotalia calcariformata was recently erroneously assumed to be a recent invasive species, increasing in population along the Israeli coast following the opening of the Suez Canal in 1869. Results from this study suggest that this species is endemic to the Israeli coast, observed here in coastal sediments pre-dating the canal opening by thousands of years. The recent attention on this species as a marker of changing environments and climate, suggested due to its current proliferation along the coastline and heat tolerance, is not an error and is worthy of continued study. We add here, in agreement, that it is a harbinger of anthropogenic change and thrives on the increased coarsening and hardening of the coastline and shallow shelf, outcomes of post-Aswan Dam decreases in the delivery of fine sediments (Kalman et al., 2022), coastal armouring, and general development.

This study demonstrates that the analysis of epiphytic foraminifera, such as P. calcariformata, can be implemented as rapid and cost-effective biostratigraphic indicators in future geoarchaeological studies at Caesarea or in similar settings elsewhere. The results have implications for the role of P. calcariformata in modern studies of benthic foraminifera on the eastern Mediterranean, mainly that it is not a recent invader, but rather a species that has thrived on the changing substrate conditions created by human activity for millennia.

Summary by ChatGPT

Steele et al. (2024) investigate how the emplacement of artificial structures, particularly King Herod’s harbor (Sebastos) at Caesarea, altered sedimentary and biological signals offshore. A significant portion of their analysis deals with depositional events linked to extreme marine inundations, including tsunami activity.

Geoarchaeological context from core C2 includes the identification of a coarse-shell unit that the authors associate with the Santorini eruption tsunami (ca. 1600 BCE). This tsunami event is known from previous studies such as Goodman-Tchernov et al. (2009) and is used here to explain anomalous faunal distributions at the base of the core— especially the offshore transport of typically shallow epiphytic foraminifera like *Pararotalia calcariformata*.

Additionally, Steele et al. note a decline in Sr/Ca ratios and changes in foraminiferal abundance that correspond to the stratigraphic levels associated with later events, including the 749 CE tsunami, reinforcing a broader regional chronology discussed by Goodman-Tchernov & Austin (2015).

Overall, Steele et al. highlight how high-resolution microfaunal and geochemical analysis can provide biostratigraphic markers for tsunamogenic and anthropogenic events. Their findings contribute to a growing recognition of tsunami-induced sedimentary structures within archaeological harbor sequences.

The study by Steele et al. (2024) also investigates sedimentary and biological indicators of environmental change in and around the artificial harbour of Caesarea Maritima, with particular relevance to identifying tsunamogenic signatures. The authors analyze cores (C1, C2), an excavated trench (W), and construction materials, applying μXRF geochemistry, magnetic susceptibility, and foraminiferal assemblages. A key observation is the presence of aeolianite-associated elemental signatures in post-construction strata—especially within discrete intervals interpreted as high-energy redeposition layers. These layers correspond stratigraphically to tsunami events proposed in prior research, in which deeper and shallower sediment materials were mixed and redistributed.

The authors interpret spikes in concentrations of specific sedimentological and geochemical markers in tandem with faunal changes as indicative of tsunamogenic transport. *Pararotalia calcariformata*, a foraminifer associated with hard substrate habitats, appears in anomalously high abundance following harbour construction and is found within layers suspected to have been disturbed by tsunami backwash or overwash. Its detachment from hard substrates and lateral offshore transport supports the interpretation of rapid, high-energy events. These observations provide both an anthropogenic signal (harbour construction) and a paleotsunami signal (event-related reworking), offering dual insight into ancient coastal dynamics.

The study suggests that both geochemical anomalies and faunal redistribution can be used to fingerprint tsunami impacts on coastal sediment records and that Caesarea offers a unique case study where tsunamogenic effects can be separated from long-term anthropogenic sediment reconfiguration.

Goodman-Tchernov and Austin (2015)

Abstract

Modern observations have shown that harbors are especially vulnerable to the effects of tsunamis, both due to their position on the coastline and the tendency for tsunamigenic eddy production within enclosed harbor basins. Presumably, this was as much the case in the past as in the present. The Roman-era mega-harbor Caesarea Maritima, which is today submerged in some parts up to 5 m below sea level, is an ideal research site for understanding these impacts. Over the past three decades, archeologists, geologists and historians have searched for the cause of the rapid demise of this harbor, turning to explanations ranging from offshore faults, seismic disturbances, general failure and deterioration, to liquefaction and settling on unconsolidated sands. While tsunamis are recorded repeatedly in the Eastern Mediterranean historical record, it has only been in the past decade that physical evidence directly attributed to tsunamigenic sediments along the Israeli coastline near Caesarea has been documented. To date, deposits from at least three tsunami events that impacted the harbor have been identified in sediment cores, coastal exposures and archeological trenches, but no laterally continuous picture has been produced. In this study, using a dense offshore survey produced by a high-resolution subbottom profiler, shallowly buried sediment horizons offshore of Caesarea produce distinctive reflectors that correlate with the tsunamigenic stratigraphic sequence identified in cores and excavations. These surface structure maps allow for a laterally extensive reconstruction of these distinctive deposits. The results have led to the following conclusions and interpretations:
  1. multiple offshore tsunamigenic horizons at Caesarea can be recognized
  2. individual tsunamigenic event horizons result in distinctive and unique surface morphologies that elucidate tsunami-based channeling/backflow processes
  3. these backwash channels can be used to assess the general physical condition of the harbor at the time of each tsunami occurrence, ultimately revealing major differences between the state of the harbor following earlier events (i.e., 2nd c. CE) vs. later events (6–8th c. CE)
We conclude that the combined acoustic-sampling approach is an effective way to document the interaction of tsunamis with harbor complexes and adjacent coastlines over millennia.

I. Introduction and background

1.1. Evidence for tsunami impacts on coastal morphology and associated structures

Coastal morphology, including adjacent landforms, artificial structures, and coastal-fringing natural features (i.e., extensive coral reefs, mangroves, e.g., Baird et al., 2005; Fernando et al., 2005; Kunkel et al., 2006; Giri et al., 2008) can all influence the impact of tsunami wave flow (Hon et al., 2007; Sugawara et al., 2012). As the inundating wave breaches the coastline, natural and man-made obstacles that obstruct or impede the wave’s force can lead to channeling and variable flow, both as the wave advances inland and retreats seawards. Such energy redistribution is also evident in affected rivers or artificial channels, in which tsunami flow will continue inland to distances far exceeding that of uninterrupted portions of the coastline (e.g., Crete 1956, Bruins et al., 2008; Okal et al., 2009; northern Japan 2011, Mori et al., 2011; Goto, 2011a; Chile 2010, Fritz et al., 2011). The tsunami return/outflow is even more influenced by the presence of structures, and therefore is typically characterized by channeling (Umitsu et al., 2007; Feldens et al., 2009), which can result in shore-perpendicular bathymetric and topographic features (Atwater et al., 2010). In Sumatra following the 2004 tsunami, evidence of such complex back-flow included filled channels, boulders moved into deeper water, movement of sand into previously silty areas, and man-made rubble immediately seaward of the shoreline (Feldens et al., 2009; Goto, 2011b). Similarly, in northern Japan following the Tohoku-Oki earthquake in 2011, canals and road features often corresponded with variations in tsunami inundation heights along the Sendai Plain.

Amongst the range of coastal structures that interact with tsunamis, harbors have been identified as locations of acute magnification and flow intensification in both simulations and field studies (Raichlen, 1966; Synolakis and Okal, 2005; Lynett et al., 2012). For example, during the 2004 tsunami, at the Port of Salalah, Oman, strong currents produced inside the harbor caused a 285 m ship to break away from its moorings and beach on a nearby sandbar after spinning and drifting for hours (Okal et al., 2006). At Port Blair, India, harbor structure damage included movement or complete collapse of the jetties (Kaushik and Jain, 2007). Examples are also available for the far-field effects of tsunamis, where harbors have been damaged while adjacent coastlines experience little inundation. One such harbor is located in Crescent City, CA; this site was damaged repeatedly following both near-field events, such as Alaska 1964, as well as far-field tsunamis, such as those generated from seismic events in 2006 (Kuril Islands) and in 2011 (Tohoku-Oki) (Griffin, 1984; Horrillo et al., 2008; Kowalik et al., 2008; Wilson et al., 2013). Widespread documentation of ships originally moored in harbors that have been displaced inland and/or damaged along the adjacent coastline during tsunamis are common; this phenomenon includes relatively small events, such as the tsunami following the 1999 Izmit earthquake in Turkey, with varying reports of wave heights, but with possible localized heights of ~6 m (Rothaus et al., 2004).

Following a tsunami, a variety of characteristic markers can be left behind, both on the shallow sea bottom and on shore, including massive debris fields, sheets of sand, muddy film, and/or eroded surfaces, amongst a list of over thirty-two published indicators (e.g., Goff et al., 2012). Depending on the specific surface conditions of the impacted coastline, e.g., surficial sediment types, strandline morphology and available unconsolidated debris, coastal zone bathymetry can be altered as contents carried within the tsunami flow drop out as the wave energy dissipates (Jaffe et al., 2012). Inland, tsunami-based deposits are generally characterized by landward thinning (Morton et al., 2007), unless interrupted by some limiting structure or topography.

The patterns of tsunami deposits and bathymetric forms created by these waves can be informative regarding the character of the affected coastline and adjacent offshore areas (Richmond et al., 2012). In northern Japan, for example, artificial channels and a highway constructed on the Sendai Plain before the 2011 Tohoku-Oki earthquake influenced the distribution of tsunami-deposited sediments and wave run-up heights (Sugawara et al., 2012), relative to the distribution of known preexisting tsunami deposits. Recognizing and mapping tsunami-related features from historical events should inform us as to the state of both natural and artificial structures on a coastline which were affected by these tsunamis, including the influences of the back-wash phase of sedimentation. In this study, the ancient harbor of Caesarea Maritima, on the eastern Mediterranean coast of Israel (Fig. 1), is presented as an ideal site to consider this tsunami-impact phenomenon, and how and whether the physical evidence for such recurring impacts might be preserved over two millennia.

1.2. Caesarea Maritima: the ancient harbor, its deterioration and demise, and recent tsunami research

When King Herod had the city of Caesarea built on the coastline of what is now Israel between 25 BCE and 9/10 BCE, he applied Roman city planning, organization and building techniques, including the costly installation of a state-of-the-art, artificial mega-harbor (Holum et al., 1988; Hohlfelder, 1988, 1996; Raban, 2009; Votruba, 2007; Raban, 2008; Fig. 1). The natural environment afforded little protection or anchorage, with the exception of periodic, remnant, exposed ridges of eolianite sandstone (locally referred to as ‘kurkar’) roughly paralleling the coastline immediately offshore. These bedrock structures are exposed and eroded lithified dunes 135,000–45,000 years old (Sivan and Porat, 2004). The harbor was constructed on portions of this bedrock and extended seaward onto unconsolidated Nile River–derived sands (Goldsmith and Golik, 1980; Neev et al., 1987; Stanley, 1989; Zviely et al., 2007), with the use of man-made foundations. Roman engineers succeeded in this task by building wooden frameworks (‘caissons’) on land, then towing them into position where they were submerged, filling them with hydraulic cement, and ultimately finishing them with above-water superstructures. Fields of large cobbles (less than 20 cm diameter) were emplaced beneath the caissons (Raban, 2008), presumably to give them added stability against erosion and undermining, suggesting that the engineers of the time were aware of the inherent risks for constructing directly on unconsolidated sandy sediments. These caissons were arranged in rows to produce the spinal walls of the harbor, completing the entire project in less than 15 years (Brandon, 1996). This efficient approach to harbor construction continues to be used today. For example, ‘Mulberry I’ and “Mulberry II”, created by the allies during WWII in preparation for the D-Day landings, were also artificial islands constructed in a similar manner for the purpose of providing supplies and reinforcements until an established harbor could be secured (Stanford, 1951; Ryan, 1959; Bettwy, 2015).

Descriptions made ~70 CE by historian Flavius Josephus describe a fully functional imperial mega-harbor, exceeding the size of most contemporaneous Mediterranean harbors (Raban, 2008). Josephus explicitly describes the expense of and investment made in the harbor's construction. Excavations have since supported these grandiose statements, revealing bulk raw building materials that traveled long journeys before arriving in Caesarea (Votruba, 2007). For example, chemical analysis of the volcanic ash (‘pozzolana’) used for producing the fast-drying hydraulic cement shows that the ash was brought from Vesuvius (Brandon, 1996; Hohlfelder et al., 2007), while the underlying cobble and rubble beds beneath the cement-filled caissons show non-local mineralogies common to Turkey, Cyprus, and parts of Greece. The wood used for the caisson frames, as was common practice in shipbuilding of the time, came from the cedar forests of Lebanon (Votruba, 2007).

However, despite the significant investment and durability of the cement used in the construction process (Jackson et al., 2012), the overall state of the harbor had significantly deteriorated by the end of the 2nd century CE, and probably even earlier, according to radiocarbon-dated sedimentological evidence showing a shift from a low-energy, harbor environment to an open-water exposed, unprotected environment during that period (Reinhardt and Raban, 1999; Reinhardt et al., 1994). Throughout the 1990s, the generally accepted presumption arising from these studies was that the harbor experienced its demise due to some combination of earthquake-related liquefaction, with some credence also given to the possibility of related tsunami, though without clear markers then to support such a hypothesis.

Caesarea harbor phases, from initial construction to the present, have been reconstructed using sedimentological, geophysical (i.e., magnetometry), and archaeological surveys (Reinhardt et al., 1994; Reinhardt and Raban, 1999, 2008; Boyce et al., 2009). The most recent summary (Reinhardt and Raban, 2008) suggests six such phases, summarized as follows:
  1. Initial construction, 1st century CE
  2. Destruction, 1–2nd century CE
  3. Unprotected (exposed to open sea; no intact harbor features), 3–4th century CE
  4. Natural/unimproved harbor, 4–6th century CE
  5. Sand infilling, 6th century CE
  6. Renovation/destruction, 6–11th century CE
Unfortunately, the foregoing summary remains vague regarding causation, as it predates later findings (Goodman-Tchernov et al., 2009) that bring to light evidence for tsunami events in both the Byzantine (4–6th c. CE) and Early Islamic (7th–8th c. CE) periods, as well as confirming an earlier suggestion of another 2nd century CE wave-based event (Reinhardt et al., 2006).

Previous geophysical research on the Caesarea Maritima harbor has included both seismic and magnetic surveys (Mart and Perecman, 1996; Boyce et al., 2004, 2009). Boyce et al. (2004) conducted a magnetic survey with the aim of determining the feasibility of using magnetic signatures to map and define the concrete installations of the harbor, as the pozzolana cement used by the Romans was iron-rich. Although the high resistivity of the kurkar bedrock proved to be challenging, the overall form of the foundations of the harbor, particularly the individual caisson forms, was discernible. Due to the significant difference between the near-coastal harbor features, which remain at their correct elevation relative to sea level, and offshore harbor features, which are now submerged up to 5 m depth, earlier work had suggested that movement along a shore-parallel fault, which became active following construction of the harbor, could be responsible for the modern elevation change (Mart and Perecman, 1996). As a result, for many years afterward, theoretical north–south trending fault lines remained on maps of Caesarea. However, after failed attempts to recognize these features in the field through additional geophysical mapping, along with jet-probe surveys of the sediments with associated seafloor excavations (Raban, 2008), such structures are now rarely included. Instead, the observed coast-parallel offset in elevation is now presumed to relate more directly to the classic challenges faced when constructing directly on bedrock versus adjacent (offshore) unconsolidated sediments. Areas of the harbor constructed seaward of the firm kurkar bedrock foundation were likely more susceptible to liquefaction, undercutting, scouring and erosion, promoting subsidence of harbor features farther offshore, whether by storms, earthquakes, or tsunamis.

Historical evidence for tsunamis in the eastern Mediterranean supports a minimum of 21 events, three referring to the city of Caesarea directly (115 CE, 551 CE and 1202 CE; Shalem, 1956; Amiran et al., 1994). Archaeologists have been aware of these events for decades (see discussion in Dey et al., 2014), but they have lacked the comparative tools or reference data to ascribe particular deposits (onshore or offshore) to tsunami-derived causes. As a result, alternative explanations for these seemingly anomalous deposits found in archaeological sites have been put forward. For example, laterally extensive shell beds encountered in terrestrial excavations in Caesarea, which could be evidence of tsunamigenic origin, have been previously ascribed to be the result either of dredging activities or as construction fill (Neev and Emery, 1989). Tsunami sedimentological research has also advanced, particularly in response to the destructive tsunamis of Sumatra 2004, Java 2009, Chile 2010 and Tohoku-Oki 2011 (e.g., Szczuciński, 2011; Goff et al., 2012; Pilarczyk and Reinhardt, 2012; Pilarczyk et al., 2012; Goto et al., 2014). As a result, there is now an extensive, robust body of comparative data for interpreting and understanding historical, prehistorical and paleo-tsunamigenic deposits (e.g., Bourgeois et al., 1988; Goff et al., 2012), which did not exist a decade ago.

This increase in knowledge has led to the recognition of more such tsunamigenic deposits worldwide, both in the archaeological and geological records (e.g., Pareschi et al., 2007; Vött et al., 2009; de Martini et al., 2010; Yawsangratt et al., 2011; Marco et al., 2014, but see also criticism of this approach in Galili et al., 2008; Morhange et al., 2014). However, despite this increased awareness, the number of tsunamigenic sedimentological deposits documented from the Levantine Sea region, and other parts of the Eastern Mediterranean, still only begins to approach the number of events recorded in the written record (Papadopoulos et al., 2014), suggesting that discovery of these deposits in this historically important part of the world remains incomplete.

Research on the demise of Caesarea's harbor (Reinhardt et al., 1994; Reinhardt and Raban, 1999) agrees generally that the timing of initial major deterioration had occurred at least by the end of the 2nd century CE (see also Raban, 1992; Raban, 1995; Reinhardt and Raban, 2008; see Hohlfelder, 2000, for alternate timing). Evidence to support the role of tsunamis in this initial damage takes the form of laterally extensive sedimentary horizons with interpreted tsunamigenic characteristics (details follow below) recorded offshore, as well as reviews of archaeological reports demonstrating the presence of corresponding deposits on land (Reinhardt et al., 2006; Goodman-Tchernov et al., 2009; Dey and Goodman-Tchernov, 2010; Dey et al., 2014).

Reinhardt et al. (2006) have characterized a tsunami deposit, found in an excavation trench (Area ‘W’, see Fig. 1C) outside of the ancient harbor, based on the presence of imbricated allochthonous shells (predominately Glycymeris violescens), with radiometric ages (1st c. BCE to 2nd c. CE) corresponding with a historically documented tsunami event at 115 CE (Shalem, 1956). Other defining characteristics of this deposit include an erosional basal contact, and mixing of included clast sizes. Goodman-Tchernov et al. (2009) have also investigated the lateral extent of this reported horizon, and identified its continuation, as well as the presence of additional interpreted but distinct tsunami horizons, based on the same criteria and an additional seven tsunami-related indicators: micropaleontological assemblage, fining-upward sequence, tilted marine installations, larger standard deviation of particle size distributions (relative to typical background), out-of-place household items, rip-up harbor mud clasts, and rafted terrestrial organic material. Reports from terrestrial archaeological excavation reports pre-dating the Reinhardt et al. (2006) initial recognition of these tsunami deposits were also revisited by Goodman-Tchernov et al. (2009) to determine whether other horizons containing possible tsunami-related inclusions had been described in the literature but not interpreted as such. Their realization was that a wide range of distinctive stratigraphic evidence for tsunami-related deposits was present. Other sorts of interpretations had included construction fill or dredging refuse dump, but these were refuted in light of new tsunami characterizations (Dey and Goodman, 2010; Dey et al., 2014). In this paper, regional high-resolution seismic profiling offshore the harbor mouth of Caesarea is combined with ongoing marine archaeological investigations to show the regional impact of multiple tsunamis on both this harbor and the adjacent coastline over the past two millennia
.

1.3. Offshore tsunami deposits

Generally speaking, the near offshore environment has not been heavily mined for tsunami evidence. While tsunami-related studies have increased exponentially in the past decade, there are far fewer studies that present shallow offshore finds. In their summary of the state of research in paleotsunami deposits Rhodes et al. (2006) asked, “Does a record of paleotsunamis exist in the near offshore stratigraphic record?”. By that time, Vandenbergh et al. (2003) had demonstrated the presence of shallow offshore deposits using both geophysical survey and coring in NW Java, Indonesia and Abrantes et al. (2005) described events correlatable to sediment core horizons in Lisbon, Portugal. Since then, a few studies of past and recent tsunami events and modeling have answered Rhodes' question in the affirmative as well. Some examples beyond the work in Caesarea (Reinhardt et al., 2006; Goodman-Tchernov et al., 2009, Dey and Goodman 2010, Dey et al. 2014) include cores collected from Augusta Bay, Italy (de Martini et al., 2010; Smedile et al., 2012), offshore boulders mapped in western Banda Aceh, Indonesia (Paris et al., 2009), Weiss and Bahlburg's (2006) modeling predictions suggesting the presence of deposits in the shallow offshore. The near offshore environment is still more poorly understood relative to terrestrial coastal areas.

4. Discussion

The interpretation of three sub-seafloor reflectors mapped offshore of Caesarea (Fig. 3) conclude with the presence of distinctive and unique coastal structural configurations at the time of past tsunami events. The mapping suggests regionally significant impedance contrasts, that were interpreted here as marking the last/uppermost expression of known tsunami deposits previously sampled, analyzed and interpreted on this margin (Fig. 4). In all cases, we assume, and this is supported by modern studies elsewhere (Paris et al., 2009), that immediately following any tsunami, complex processes of alteration and erosion occur, particularly in depths exposed to storm activity and other coastal processes (e.g., long shore transport). In this part of the Mediterranean, these tsunami deposits, or what part of them is preserved after exposure to later storm and long-shore transport effects, are buried under Nile River–derived sands. Therefore, we suspect that the reflector maps of the two subsurface reflectors (Fig. 6B, C) does not give a reading of what the sea bottom looked like immediately following the tsunami, but at the time of the tsunamite’s eventual burial, which could be a matter of decades or more. Therefore, the apparent drainage features we observe are probably only preserved remnants of tsunami backwash features which, at the time of their formation, would have been even more distinctive and pronounced, as is true in modern analogues (Bahlburg and Spiske, 2012; Feldens et al., 2009; Hori et al., 2007; Paris et al., 2009). Each event has a unique signature that relates to the state of the coastline and the structures present at that time.

The deepest reflector, ‘C’ (Fig. 3B), which is associated here with what is left of the Santorini-age tsunamite, is not sufficiently preserved offshore Caesarea to identify except in topographic lows in the kurkar topography (Fig. 3B), and in deeper water. The unaltered coastline in this area is high-energy, with little natural protection, which is one of the reasons that specialized engineering methods were required to create the Caesarea harbor. Therefore, prior to the harbor’s construction, at the time of the Santorini-age event (Fig. 4), tsunami deposits in shallow water would not have had a good chance for preservation due to their exposure to the open sea, but were more likely redistributed and transported during storms; we also see such storm-related redistribution today. In contrast, later events following the construction of the harbor have a greater chance of preserving due to the more protected nature within the harbor area, even if only in relative terms, from the full force of incoming storms. This is observable today during storms in which the waves are noticeably attenuated within the semi-protected harbor bay, despite the harbor’s generally dilapidated condition. Sedimentological evidence clearly shows the presence of the Santorini horizon in water depths > 10 m (Fig. 4). In area ‘W’ (Fig. 1C; 4, upper right) the stratigraphic sequence includes a major hiatus (~3 kyr of missing sediment), which includes the level at which the Santorini horizon would have been expected. We expect such a hiatus in area W, as it is located just outside the harbor entrance, and would have experienced focused outgoing flow capable of substantial erosion and scouring during the back-channeling phase of a tsunami. In addition, because harbors are known to intensify the effects of tsunamis, any Santorini-aged tsunami deposits in shallow water that survived until the construction of the harbor would have been vulnerable to further erasure following the first of the post-harbor construction tsunami events (Fig. 4).

Reflector B’s surface morphology includes a main channel complex that corresponds approximately with the position of the harbor entrance (Fig. 6C). Because Caesarea’s harbor is believed to have been in good condition at the time of the 2nd century tsunami, the incoming wave must have encountered an intact and standing outer harbor mole, which would have forced abrupt shoaling of the incoming wave, scouring deeply the area immediately outside the harbor, while also breaching the tops of man-made features. Incoming wave inundation must also have run up within the harbor, as well as along the coastline north and south. However, during subsequent retreat of the wave, that outflowing water would have concentrated through the harbor mouth, between the reinforced moles (Fig. 2), preferentially scouring and eroding the region immediately outside the harbor entrance and depositing larger deposits farther offshore, as is evident in the ~80 cm 2nd century deposit in Area W (Reinhardt et al., 2006). Estimating the velocity of the flow exiting the harbor mouth during the 115 CE event is possible, because archaeological evidence exists for the movement and toppling of an artificial island that stood at the harbor entrance at that time (Raban, 2008). During excavations there in the late 1990s, concrete was exposed and a vertical contact between cement layers of different fabrics was recorded. These cement layers are a remnant of the construction process, during which different cement mixes were used at different phases of filling the wooden caissons (Brandon, 1996, Hohfelder et al., 2007). At the time of construction, after the cement cured, the different concretes layers lay horizontal upon one another; therefore, any shift from the original position at construction can be identified due to the offset of that horizontal contact. In the case of the tower, the near-vertical contact indicates at least a 90° shift of the caisson after the harbor was completed. It was also observed that no wood was preserved on any outer surface of the island, whereas typically protected, unexposed sides of the caissons included some preserved wood, again suggesting that all sides of the island, which was essentially once a wood-faced concrete cube, had been exposed on all sides fully to the elements at some point of time, a situation only possible with the turning of the caisson. Artifacts found around the base of the toppled tower post-date the 1st century CE, with the earliest coin found aged at 144 CE. These deposits are not beneath the tower, but rather along the edges of the tower within the typical scouring areas where debris is regularly trapped in harbor entrances. Excavations did not tunnel fully below the towers due to safety concerns. Such artifacts might provide an age maximum for the timing of the tower’s collapse, so the observed damage best correlates with the historic tsunami a few decades earlier in 115 CE. As the minimum size of this island was at least 25 m³, and as its concrete has an estimated minimum density of ~2400 kg/m³, its estimated weight should exceed 60 metric tons. Toppling such an island would have required significant force, and is analogous to damage that has been recorded to concrete harbor structures recently during the 2011 Tohoku-Oki tsunami in northern Japan events (Fig. 7, Ewing et al., 2013).

We hypothesize that the shallower subsurface reflector ‘A’ is the buried surface formed by backflow associated with the 8th century CE (possibly 749 CE) tsunami; this surface could also represent a composite with the 6th century CE (551 CE) event. We suggest that the multiple, distributed channels observed in that reflector’s surface morphology (Fig. 6B) represent a complex back-channeling product produced by the less-organized/more degraded character of the harbor at that time. The Byzantine Era (4th–7th c. CE) was a busy time for Caesarea commercially, but with the exception of a 500 CE renovation, the harbor consisted primarily of the intermediate harbor (Fig. 1D) with very little, if any, surface presence of the outer harbor mole/jetty complex (Figs. 1D, 2; Reinhardt and Raban, 1999). Presuming that the map of reflector “A” gives us the ~post-8th century event state of the coastal sea bottom, the harbor would have been in an even more degraded condition through the Early Islamic (7th–11th c. CE) period, with multiple disorganized approaches rather than a single cohesive entrance (Fig. 6B, right). Recently this chaotic character of the outer harbor at that time was reinforced with the discovery of thousands of gold coins dating to the 10–11th century that were presumably part of a shipwreck discovered on top of the submerged harbor in a depth of only 7.5 m, which could only be possible if that area was not a cohesive harbor at the time. Ship ballast concentrations and refuse have been recognized outside the harbor in a roughly shore-parallel, elongated oval shape that agrees with the pattern of debris that would be expected in an anchoring refuge for commercial transactions, given prevalent wind patterns and typical anchoring scope ratios (Boyce et al., 2009). This overlying refuse may be deposited immediately above the two tsunami horizons in question, suggesting that whatever condition the harbor was in prior to the 749/551 CE events, it was even more heavily compromised afterwards. As a result, by the 6th century CE, commercial ships likely had to anchor offshore as a standard practice.

Recently, in continuing efforts to link terrestrial archaeological stratigraphy to the offshore sequence, evidence has been gathered to suggest that there are two distinct stratigraphic horizons with tsunamigenic features, one dating to the late Byzantine (~6th century CE) and the second to the Early Islamic (8th century CE) periods (Fig. 4). Much of this evidence comprises of shell layers described in the terrestrial excavations that were previously interpreted as dredge debris (see Dey et al., 2014 for detailed discussion). However, thus far, only one offshore layer has been identified (Fig. 4). The original dating of that offshore horizon (Goodman-Tchernov et al., 2009; Fig. 4) was limited to a few sherds of ceramics that were ceramic types that remained in use over a long period that included the late Byzantine period and into the Early Islamic era (~5–8th c. CE), and only one radiocarbon date has been obtained from shell material immediately above the horizon. After a more detailed review of the dating methods used for that horizon in previous studies, recent finds from shallow (< 3 m) water excavations, and review of archaeological reports from the hippodrome coastal area (Dey et al. 2014) we suggest that the single horizon is actually the result of two separate tsunami events that occurred relatively close in time (~200 years), resulting in a single deposit. An upper date of 900–1050 CE (radiocarbon, Goodman-Tchernov et al., 2009) from the horizon immediately above the deposit, gives an upper limit for the tsunamite age, but also supports the possibility that both 6th and 8th century CE tsunami events contributed to the preserved horizon.

Following any tsunami event, sediments eroded and redeposited by the waves are exposed to later erosional and depositional processes. For Caesarea, the normal depositional regime, dominated by sandy sediments from the Nile River to the south, typically provides a positive sediment budget necessary for burying the tsunamite. However, short intervals between tsunami events means that less inter-event sediment is available to bury and preserve the underlying tsunamites. If a buried tsunamite is exposed and eroded during a later tsunami, then that material can be mixed and redeposited together with the later event, resulting in a single horizon.

Evidence for such mixing offshore of Caesarea exists in multiple forms. First, archaeological descriptions demonstrate the presence of tsunamigenic deposits on land south of the harbor, within the adjacent hippodrome area (see Figs. 1 and 2), of both 6th century A.D. and 8th century A.D. deposits (Dey and Goodman, 2010; Dey et al., 2014). In excavations of the shallow intermediate harbor (TN area, Fig. 1C; Reinhardt and Raban, 2008), there is an extensive deposit of mixed (Early Islamic–Byzantine, 4th to 8th century CE) refuse, ranging from high-value intricate items of varying erosion state and exposure—suggesting broad mixing of typical harbor refuse (e.g., broken amphora/pots) and newly introduced, undamaged domestic wares and personal items (e.g., intricate hair combs, fine sections of Islamic coins, statuette, a satchel of copper coins). Unlike other harbor deposits, these materials are of broad origin (domestic, commercial, religious), value range and preservation state, suggesting the kind of non-deliberate and rapid burial a tsunami event would produce. In addition, because the ages of the ceramics found in this excavation range from Early Islamic to late Byzantine (6th through 8th centuries CE), no distinctive stratigraphy offshore today separates what may have been two distinct tsunami events.

The expression of the different horizons in this offshore seismic survey is only possible due to the significant acoustic contrast in the physical properties between the tsunami event layers vs. the background, non-tsunami sediments (Fig. 5). In the case of Caesarea, the background Nile River–derived sands are especially homogenous (siliciclastic, quartz-rich fine sands with a highly conservative mode value of ~169 μm), while the tsunamigenic layers consist of a range of grain sizes and inclusions of varying materials with far wider-ranging physical properties (shell, broken kurkar cobbles, foreign ballast, pottery, etc.). As a result, Caesarea may represent ideal conditions for the application of geophysical methods to tsunamite identification in the coastal zone. Other areas of the Mediterranean, and the world, where coasts with more meandering geomorphological features likely exhibit more variations and micro-environments in their natural background conditions, tsunamite definition is likely to be more problematic. Nonetheless, we feel that our results merit the effort to attempt similar merged mapping and archaeological excavations/sampling elsewhere.

5. Conclusions

The results of the high-resolution seismic survey of Caesarea support previous studies that have argued for the presence of laterally extensive tsunamigenic deposits in and around that ancient harbor complex. Santorini-age tsunami deposits are present, but not everywhere identifiable. The earlier interpretation that the ancient harbor of Caesarea was relatively intact at the time of the first historically documented tsunami that would have impacted it, ~1–2nd century, possibly 115 CE, is supported by the presence of pronounced (backwash) channels in association with the entrance to the ancient harbor. In contrast, the harbor's appearance was much degraded by the time of a known 8th century tsunami (749 CE), which is emphasized by the presence of a series of preserved remnant channels, testifying to multiple backwash paths. These preserved paleo-bathymetric features could be recognized at other archaeological sites and may provide a new preserved indicator for ancient tsunamis, further reinforcing the usefulness of the offshore record, particularly relative to the relatively quickly altered and erased terrestrial record (Szczuciński, 2011).

Caesarea, an ancient urban harbor city with a concrete harbor comparable to many harbors of today, also provides insight into the effects of tsunamis on harbors and the nature of preserved deposits in and around them. We suggest that the intensification and magnification of tsunamis within harbors could provide an additional dataset for targeting and identifying non-documented tsunamis and improving the understanding of their impact on harbor structures, enhancing and expanding on the tsunami catalogues, as well as better understanding broader near and far-field effects elsewhere. A multitude of harbor sites both nearby (e.g., Tyre, Sidon, and Alexandria) and worldwide could contain these useful deposits.

Goodman-Tchernov et al. (2009)

Abstract

A sedimentary deposit on the continental shelf off Caesarea Maritima, Israel, is identified, dated, and attributed to tsunami waves produced during the Late Bronze Age (ca. 1630–1550 B.C.E.) eruption of Santorini, Greece. The sheet-like deposit was found as a layer as much as 40 cm thick in four cores collected from 10 to 20 m water depths. Particle-size distribution, planar bedding, shell taphocoenosis, dating (radiocarbon, optically stimulated luminescence, and pottery), and comparison of the horizon to more recent tsunamigenic layers distinguish it from normal storm and typical marine conditions across a wide (>1 km²) lateral area. The presence of this deposit is evidence that tsunami waves from the Santorini eruption radiated throughout the Eastern Mediterranean Sea, affecting the coastal people living there. Dates for the tsunami deposit bracket both the so-called “high” and “low” chronology for the Santorini eruption. In addition to resolving the question of the extent of tsunami impact from the Santorini eruption, the research presented also provides a new means of discovering, identifying, and studying continuous records of paleotsunami deposits in the upper shelf coastal environment. The latter is key to understanding past events, better interpreting sedimentological records, and creating stronger models for understanding tsunami propagation, coastal management, and hazard preparation worldwide.

Introduction

The Plinian eruption of Santorini (Thera, ca. 1630–1550 B.C.E.; Friedrich et al., 2006; Manning et al., 2006), Greece, in the Late Bronze Age, at an estimated 7.1 on the Volcanic Explosivity Index (McCoy et al., 2000), was one of the largest eruptions in human antiquity (Friedrich et al., 2006; Manning et al., 2006; McCoy and Heiken, 2000; Sigurdsson et al., 2006). The extent to which the eruption precipitated tsunami waves has long been debated, as has the question of the range and magnitude attained by such waves (Yokoyama, 1978).

The position that the Santorini eruption resulted in tsunami waves is based on the reporting of tsunami deposits along coastal areas of Greece and Turkey (Fig. 1A) and comparison of that event with tsunami waves associated with historic eruptions that involved similar eruptive mechanisms (Manning et al., 2006; McCoy and Heiken, 2000; Sigurdsson et al., 2006; Yokoyama, 1978). Computer models incorporating this evidence have shown that near-field and far-field wave amplitudes were significant, with maximum wave amplitudes of 26 m and inland inundation to 200 m along the coast of Crete (Bruins et al., 2008; Dominey-Howes et al., 2006; McCoy and Heiken, 2000; McCoy et al., 2000; Yokoyama, 1978). If the waves propagated from the event were strong enough to reach the coast of Israel, 1000 km away, then presumably other Late Bronze Age coastal sites across the Eastern Mediterranean littoral will likely have been affected as well.

Tsunami literature is full of sedimentary studies of post-tsunami deposits; however, these studies are mainly terrestrial and break off abruptly at the coastline, or at best the low tide mark (Choowong et al., 2008; Hawkes et al., 2007). It has been postulated (Weiss and Bahlburg, 2006), and is shown in this study, that the offshore upper shelf environment can contain preserved tsunami deposits. Traditionally, marine sediments discovered in terrestrial deposits have been used to identify tsunami deposits and assess tsunami magnitude (Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Jankaew et al., 2008; Nanayama et al., 2003). Preserved upper shelf marine tsunami deposits are a new source for field-based tsunami evidence (Reinhardt et al., 2006). The general exclusion of these types of deposits from past literature (with the exception of Krakatau; van den Bergh et al., 2003) is likely due to the difficulty of differentiating tsunamigenic layers from storm signatures and subtle mixing in the nearshore zone.

Method

Four sediment cores were collected (Fig. DR1 in the GSA Data Repository1) and one area (area W) was re-excavated with dredges in the sandy upper shoreface (~15 to 20 m below msl) offshore of Caesarea (Fig. 1B), in order to
  1. determine the lateral extent of a previously identified second century (C.E.) tsunamite (Reinhardt et al., 2006)
  2. test hypotheses related to defining and identifying tsunami deposits using multiproxy methods
  3. differentiate the deposit from possible archaeological anthropogenic sedimentation
  4. determine the appearance of a tsunami deposit sequence seaward of the coastline
The major aims of the analysis were to determine sediment characteristics (i.e., micropaleontology, granulometry) in a known tsunamite as a means of differentiating between normal large storm cycles and tsunamis, and identifying the maximum extent of the tsunamigenic deposit, based on established tsunamite characteristics (Bruins et al., 2008; Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Donato et al., 2008; Morton et al., 2007; Reinhardt et al., 2006).

The study presumed that tsunamite horizons would be areally extensive and thus visible in a majority of the cores, and hypothesized that the deposits would grow gradually thinner seaward. Hence, at greater depths the deposits would be expected to become less visible, with fewer tsunamigenic indicators. The chronology of the cores was determined using ceramic finds, radiocarbon, and optically stimulated luminescence (OSL) dating (Tables DR1 and DR3). Local sea-level change (Sivan et al., 2001) would not have dramatically altered the cores’ positions relative to water depth (Fig. 2).

Tsunamigenic indicators, as defined by previous tsunami studies (Bruins et al., 2008; Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Donato et al., 2008; Morton et al., 2007; Reinhardt et al., 2006) (Figs. 2 and 3), included erosional lower contacts, fining-upward particle-size distribution, imbrication of inclusions, individual or groups of molluscs, mixed wear and poor sorting of molluscs, change or distinctive microfossil assemblage (foraminifera), rip-up clasts, household goods and high-value anthropogenic cultural material misplaced in marine context, rafted organics or pumice, unidirectional tilting of marine installations, and well-rounded beach zone pebbles in deeper contexts. Based on comparisons of particle-size distributions of known events within the cores (Fig. 4), a unique sorting based on particle-size distribution was also recognized as a tsunamigenic indicator at this location. Sediment characteristics of the tsunamigenic and intermediary deposits were described and compared.

Results And Discussion

A minimum of one and a maximum of three tsunamigenic horizons were identified in each of the cores (Figs. 2 and 3; Figs. DR2–DR6). Event 1, ca. 1.5 ka ago, corresponds chronologically with a historically documented event of 551 C.E. (Amiran et al., 1994; Mart and Perecman, 1996; Salamon et al., 2007); it is well represented across all of the cores and trenches, and is also present in the findings of previous archaeological excavations (Raban, 2008; Reinhardt and Raban, 2008, 1999; Reinhardt et al., 2006, 1994, 1998), where this horizon was interpreted solely as isolated deposits of jettisoned archaeological materials, or a storm layer (Boyce et al., 2009; Reinhardt et al., 2006). The new results complement the previous interpretation that onloading and offl oading of goods occurred outside of the harbor (Boyce et al., 2009), particularly in the light of possible tsunami-related damage to the harbor. Tsunamite indicators of event 2, ca. 2 ka ago, which correspond with an historical event of 115 C.E. (Amiran et al., 1994; Kortekaas and Dawson, 2007; Mart and Perecman, 1996), are visible in all of the cores. Event 3, OSL and radiocarbon dated to 3630–3410 cal (calibrated) yr B.P., and thus to the period of the Santorini eruption, was identified in cores 1–4. The Santorini-age event differs from the more recent events in the amount of archaeologically related materials in the deposits (Fig. 3B). During events 1 and 2, Caesarea was already built, and therefore the horizon is rich with related anthropogenic debris from the well-populated port city, whereas no major city is known to have existed at that site during event 3 (Late Bronze Age). Therefore, many of the tsunamigenic indicators present during events 1 and 2 are irrelevant for event 3.

Distinguishing between storm and tsunami deposits has long been a central challenge within tsunami research. Tsunami and storm waves differ in the depth to which they can disturb the sea bottom; as water depth increases, storm influence becomes less apparent, while tsunami influence remains (Weiss and Bahlburg, 2006), and these influences can be visible in particle-size distributions. Contour-map plotting of particle-size distributions visually represents differences in distribution more clearly than with conventional means of data expression (Donato et al., 2008; Beierle et al., 2002), and here provides a very useful tool for differentiating between typical storm events and tsunami events (see Fig. 4 and Figs. DR7 and DR8). For example, particle-size distribution results from the tsunamigenic horizons of core 1 (14.3 m water depth) are characterized by a wider range of grain sizes and poor sorting relative to nontsunamigenic horizons. In addition, large storm horizons are visible between the tsunamigenic events, characterized by a range of particle sizes greater than nontsunamigenic horizons, but more limited than tsunamigenic horizons. In comparison to core 1, the storm deposits particle-size distribution signatures in core 2 (20 m water depth) are nearly nonexistent, while the chronologically correlated tsunamigenic horizons are still visMode Particle Sizeible. Thus, the use of particle-size distribution analysis for interpretation makes it possible to recognize tsunamigenic horizons that would be otherwise untraceable. In addition, multivariable K-cluster analysis of the particle size distributions from core 1 ( 15 m) demonstrated that the tsunamigenic horizons clustered independently, while the storm horizons remained within the range of nontsunamigenic horizons (Figs. DR7 and DR8).

Area W (Figs. 1–3) lacked evidence for the Santorini event due to a pronounced disconformity represented by a missing section of at least 2 ka worth of deposits (Reinhardt et al., 2006). This may be the result of erosion and scouring against the harbor structure during the Roman period tsunami (event 2). In the deeper cores, outside the influence of the harbor structure, traces of the Roman period event remained. In the terrestrial and nearshore zone, no data are available for Santorini-age horizons because this exceeded the depths of the archaeological excavations. There are two claims of Santorini-derived deposits from the Tel Aviv area (Neev et al., 1987; Pfannenstiel, 1960) that have been disregarded as unreliable due to poor dating and weak, single variable evidence (rafted pumice, high terrace shell bed). In light of these new findings, these previous claims may be worth revisiting.

Conclusions

Tsunami horizons coincident with the Santorini eruption were identified from upper shelf submerged sediment cores in the Eastern Mediterranean offshore from Caesarea, Israel, based on the correlation of well-dated horizons with tsunamigenic indicators. The continental shelf contains a wealth of undisturbed deposits to better inform and complete the paleotsunami record worldwide, particularly for the many areas where shelf bathymetry similar to that of the Eastern Mediterranean exists. These findings constitute the most comprehensive evidence to date that the tsunami event precipitated by the eruption of Santorini reached the maximum extent of the Eastern Mediterranean.

Caesarea Harbor Earthquake and/or Tsunami - Late 1st - 2nd century CE

Figures

Figures

  • Fig. 1- View of ancient harbor of Caesarea from Reinhardt and Raban (1999)
  • Fig. 2 - Stratigraphic Sections from Reinhardt and Raban (1999)
  • Fig. 3 - Possible harbor configurations through time from Reinhardt and Raban (1999)
  • Fig. 2 - Herodian-phase mole demonstrating ~2000 years of a stable sea level from Dey et al(2014)

Discussion
Discussion

References
Notes by JW

New Notes by JW

Research on the demise of Caesarea's harbor (Reinhardt et al., 1994; Reinhardt and Raban, 1999) agrees generally that the timing of initial major deterioration had occurred at least by the end of the 2nd century CE (see also Raban, 1992; Raban, 1995; Reinhardt and Raban, 2008; see Hohlfelder, 2000, for alternate timing). Evidence to support the role of tsunamis in this initial damage takes the form of laterally extensive sedimentary horizons with interpreted tsunamigenic characteristics (details follow below) recorded offshore, as well as reviews of archaeological reports demonstrating the presence of corresponding deposits on land (Reinhardt et al., 2006; Goodman-Tchernov et al., 2009; Dey and Goodman-Tchernov, 2010; Dey et al., 2014).

Reinhardt et al. (2006) have characterized a tsunami deposit, found in an excavation trench (Area ‘W’, see Fig. 1C) outside of the ancient harbor, based on the presence of imbricated allochthonous shells (predominately Glycymeris violescens), with radiometric ages (1st c. BCE to 2nd c. CE) corresponding with a historically documented tsunami event at 115 CE (Shalem, 1956). Other defining characteristics of this deposit include an erosional basal contact, and mixing of included clast sizes. Goodman-Tchernov et al. (2009) have also investigated the lateral extent of this reported horizon, and identified its continuation, as well as the presence of additional interpreted but distinct tsunami horizons, based on the same criteria and an additional seven tsunami-related indicators: micropaleontological assemblage, fining-upward sequence, tilted marine installations, larger standard deviation of particle size distributions (relative to typical background), out-of-place household items, rip-up harbor mud clasts, and rafted terrestrial organic material. Reports from terrestrial archaeological excavation reports pre-dating the Reinhardt et al. (2006) initial recognition of these tsunami deposits were also revisited by Goodman-Tchernov et al. (2009) to determine whether other horizons containing possible tsunami-related inclusions had been described in the literature but not interpreted as such. Their realization was that a wide range of distinctive stratigraphic evidence for tsunami-related deposits was present. Other sorts of interpretations had included construction fill or dredging refuse dump, but these were refuted in light of new tsunami characterizations (Dey and Goodman, 2010; Dey et al., 2014). In this paper, regional high-resolution seismic profiling offshore the harbor mouth of Caesarea is combined with ongoing marine archaeological investigations to show the regional impact of multiple tsunamis on both this harbor and the adjacent coastline over the past two millennia
Tsunamite indicators of event 2, ca. 2 ka ago, which correspond with an historical event of 115 C.E. (Amiran et al., 1994; Kortekaas and Dawson, 2007; Mart and Perecman, 1996), are visible in all of the cores

Distinguishing between storm and tsunami deposits has long been a central challenge within tsunami research. Tsunami and storm waves differ in the depth to which they can disturb the sea bottom; as water depth increases, storm influence becomes less apparent, while tsunami influence remains (Weiss and Bahlburg, 2006), and these influences can be visible in particle-size distributions. Contour-map plotting of particle-size distributions visually represents differences in distribution more clearly than with conventional means of data expression (Donato et al., 2008; Beierle et al., 2002), and here provides a very useful tool for differentiating between typical storm events and tsunami events (see Fig. 4 and Figs. DR7 and DR8)

the use of particle-size distribution analysis for interpretation makes it possible to recognize tsunamigenic horizons that would be otherwise untraceable. In addition, multivariable K-cluster analysis of the particle size distributions from core 1 ( 15 m) demonstrated that the tsunamigenic horizons clustered independently, while the storm horizons remained within the range of nontsunamigenic horizons (Figs. DR7 and DR8)

Area W (Figs. 1–3) lacked evidence for the Santorini event due to a pronounced disconformity represented by a missing section of at least 2 ka worth of deposits (Reinhardt et al., 2006). This may be the result of erosion and scouring against the harbor structure during the Roman period tsunami (event 2). In the deeper cores, outside the influence of the harbor structure, traces of the Roman period event remained Underwater geoarchaeological excavations on the shallow shelf (~10 m depth) at Caesarea, Israel, have documented a tsunami that struck and damaged the ancient harbor at Caesarea

The tsunami deposit consisted of an ~0.5-m-thick bed of reverse-graded shells, coarse sand, pebbles, and pottery deposited over a large area outside of the harbor. The lower portion of the deposit was composed of angular shell fragments, and the upper portion of whole convex-up Glycymeris spp. shells. The sequence records tsunami downcutting (~1 m) into shelf sands, with the return flow sorting and depositing angular shell fragments followed by oriented whole shells. Radiocarbon dating of articulated Glycymeris shells, and optically stimulated luminescence (OSL) dates, constrain the age of the deposit to between the first century B.C. and the second century A.D., and point to the tsunami of A.D. 115 as the most likely candidate for the event, and the probable cause of the harbor destruction On 13 December A.D. 115, a tsunami struck the ancient port city of Caesarea (Israel) and was recorded in the Talmud (Shalem, 1956; Amiran et al., 1994). According to the description, the wave impacted the Levantine coast with effects recorded at Caesarea and Yavne (Fig. 1). The tsunami was likely caused by a powerful earthquake that destroyed the city of Antioch (Fig 1; Ambraseys and Jackson, 1998) and originated somewhere along the eastern Cyprean Arc (Ben-Avraham et al., 1995).

The construction of Caesarea's harbor by Herod the Great in 21 B.C. is well documented by excavation work and descriptions of the harbor by the historian Josephus Flavius (Whiston, 1999; Holum et al., 1988). The reasons for the rapid decline in the harbor, about one century later, are less clear, and heavily debated (Reinhardt and Raban, 1999; Hohlfelder, 2000). However, the favored interpretation has been the catastrophic destruction of the harbor by an earthquake; although the role of a tsunami has been considered, no conclusive evidence has ever been found (Raban, 1992, 1999; Reinhardt and Raban, 1999; Mart and Perecman, 1996)


While we do not have the resolution in radiocarbon, optically stimulated luminescence (OSL), or ceramic dating to precisely confine the event to a given year, or decade, the A.D. 115 tsunami is an excellent candidate for creating the deposit We used this approach at Caesarea to document a thickly stratified shell deposit whose taphonomic characters and dating (14C, OSL, material culture) indicate that it was formed by the 13 December A.D. 115 tsunami We excavated trenches to depths of up to 2.2 m at several sites outside the harbor as part of an earlier study at Caesarea (Boyce et al., 2004). At three sites (W4, W6, and W7) the trenches revealed a sequence of shelf sands containing an upper horizon of Byzantine-era ship's ballast and pottery (0.5 m thick, Unit B) and an underlying distinctive shell layer at 1–1.5 m depth. The thickness of the shell horizon varied (0.2–1 m) but could be correlated across excavation areas as a continuous horizon. The shell deposits were predominantly Glycymeris (mostly violescens), which inhabits the infralittoral zone, typically below 18 m water depth (Barash and Danin, 1992). Two sediment samples from each shell subhorizon in Area W7 (~1000 cm³, 700–800 g) were sorted by shell content, and fractional weight abundance (%) was calculated for whole unrounded Glycymeris shells, angular Glycymeris fragments, rounded whole Glycymeris shells, and other shell fragments. The whole Glycymeris shells (unrounded) were further sorted into size fractions.

The shell taphocoenosis was clearly different between the modern storm active unit (A and top of B) and the tsunami shell beds (D1 and D2). The ballast deposit (Unit B) contained abundant whole Glycymeris shells (55%) with a large percentage of rounded shells (28%), and the size distribution of the whole shells was skewed with a predominance of shells in the 6–10 mm range. The taphonomic characters of the shell in the upper ballast layer were commensurate with the accumulation of shell amongst the ballast stone from multiple storm events. This is typical storm deposition, and has been seen elsewhere in the harbor excavations (e.g., Reinhardt, 1999). There was no distinct orientation to the shells and they were predominantly whole, rounded, disarticulated Glycymeris shells.

In contrast, the deeper shell horizon was characterized by two subunits (D1 and D2), which were separated by a sharp uneven contact. The upper horizon (D1) consisted of 73% convex-up oriented disarticulated Glycymeris shells, a smaller quantity (12%) of rounded shells, angular fragments (11%), and other shell material (4%), and the size distribution of the whole Glycymeris shells displayed low peakedness with a relatively even distribution through the size range. Horizon D2 was different in taphonomic character from Unit B and D1, as it consisted of 86% angular fragments, 10% whole shell, 4% other shell, and no rounded fragments. The distribution of whole shell was also different, as it was skewed toward smaller valves with more than 80% of the valves being less than 10 mm in diameter. These taphonomic characters are distinctly different than those of the shells in the ballast deposit (Unit B).

There is taphonomic evidence of fragmentation in the lower portion of the shell horizon (Unit D2), which can only be indicative of a tsunami. The high percentage of fragmented shells (and abundant stress fractures), along with their angular breaks, is atypical of storm shell accumulations on the shelf. The Glycymeris shells are very robust with no preexisting weakness, and tend to degrade through abrasion rather than any significant breakage, as seen in the shells in the upper ballast deposit. The abundance of fragmented Glycymeris shells in the lower part of the shell unit, and their lack of rounding, indicates a high-energy event horizon with no subsequent reworking since deposition. The fragmentation is consistent with intense wave turbulence, shell-to-shell impacts, and shells striking the harbor moles or bedrock under high wave energy, as generated by a tsunami.

The accumulation of whole Glycymeris shells (D1) on top of the shell fragments (D2) likely indicates differential settling of shells after the tsunami. The smaller angular fragments would settle out of the water column first, followed by the larger valves, which would sink in a helical path and at a slower rate (Brett, 2003). The convex-up orientation is due to deposition under a unidirectional current, and likely from the return flow of the tsunami wave. This is a characteristic orientation for bivalve shells in riverbeds and in tidal currents (Brett, 2003; Allen, 1984). In the modern environment, densely packed convex- up Glycymeris orientations were observed in shallow (1–2 m), narrow (2–3 m) rills in the sandstone bedrock to the east of the excavation sites, where strong storm surge waves orient the shells. The shells from the upper tsunami unit were oriented convex upwards but were not stacked vertically and did not form any "nests," indicating rapid continuous deposition without sustained oscillatory currents reorienting the shells (Brett, 2003; Allen, 1984). The thickness of the shell horizon is atypical of the normal shelf stratigraphy, as storm accumulations are normally composed of thinner shell layers because the storms cannot sort and concentrate enough shell material to form an accumulation up to 50 cm in thickness.

Additional evidence for the tsunami origin for the shell deposit comes from the distribution of 14C and OSL dates, and pottery ages, which showed intense scour of the seabed. Articulated Glycymeris shells were found in the sand (E) below the shell unit, in the shell horizon (D1 and D2), and in the overlying sand (C) up to the ballast deposition, which were 14C dated from W7. OSL dates of the sands from the same units from W6 resulted in similar ages. The 14C dates from the lower sand unit (E) of 3130–2841 B.C., and from the overlying fragmented shell unit of 81 B.C. to A.D. 125, were corroborated with OSL dates of 2375–3133 B.C. and 238 B.C. to A.D. 216, and with small pottery fragments characteristic of the first and early second centuries A.D. (‘Eastern Sigillata B’ and Early Roman bag-shaped jars of ‘Riley 1A type’; Raban, 2004), indicating a significant erosional scour that is also seen in the truncation of faint sedimentary and bioturbation structures in Unit E. The overlying sand (Unit C) has OSL and 14C dates similar to the tsunami deposit. Such evidence is commensurate with scour from a tsunami wave, deposition of shells, followed by infill of sand from the receding tsunami and/or through storm deposition after the event. The rapid infilling of the erosional scour is indicated by the articulated Glycymeris shells within Unit C, which indicate little reworking. Considering the error on the 14C and OSL dates, it could have taken anywhere from years to decades for the shelf to re-equilibrate and infill the tsunami scour. Abundant ceramic material from the fourth to sixth centuries A.D. was present in Unit B, indicating the upper limit of the active storm layer within the stratigraphy.

The pottery in the shell horizon indicates that the tsunami occurred after the construction of Caesarea in the late first century B.C., and after Josephus described the harbor in grand terms between A.D. 75 and 79. Josephus referred to seismic events throughout the region, and had the harbor withstood a tsunami, he would have mentioned it, as a glorification of the harbor's strength and engineering prowess (Josephus Flavius; Antiquities of the Jews XV.9.6, in Whiston, 1999). The radiometric dates further constrain the event to no later than A.D. 200, making the A.D. 115 tsunami the likely candidate for the shell deposit. No complete or accurate record of all tsunami events exists; however, the other known events for the Levantine coast are either too old (20–26 B.C. flooding at Pelusium) or too young (A.D. 306 destruction at Sidon and Tyre; Mart and Perecman, 1996)
In a previous study (Reinhardt and Raban, 1999) we presented evidence indicating seismic damage in the first to second centuries A.D. that severely compromised the Caesarea harbor structure. We presented evidence that seismic activity was the cause of the destruction of the harbor; although, considering the new data, some of the evidence could equally be interpreted as a result of a tsunami.

The harbor mole was constructed of large (390 m³) concrete blocks (caissons) laid on the seafloor (e.g., Raban et al., 1999). The impact of the tsunami bore would have shifted the mole's foundation and undermined its shoreward edge, causing the offset of the caissons as observed in the modern harbor ruins (Raban et al., 1999; Reinhardt and Raban, 1999). The impact of the tsunami may have also loaded the underlying sediments to the point of liquefaction, leading to further foundering of the caissons. It is envisioned that during the impact of the tsunami bore, significant quantities of shoreface sediments and shell materials would have impacted onto the mole and bedrock surfaces, generating a large volume of broken shell material. The articulated Glycymeris shells in the tsunami deposit indicate transport from the deeper shelf, as the shallowest habitation depth for these bivalves is 18 m. In the harbor itself, the tsunami and resulting seiche would have been highly destructive, causing further erosion and undercutting of the harbor mole. High-energy conditions represented in the first- to second-century A.D. sediments from the inner harbor may be from this event (Reinhardt and Raban, 1999). In the subsequent return flow phase, further erosion of the shelf may have occurred, and the graded shell bed (Unit D) records the sorting and deposition of the shell materials with the waning tsunami. The inclusion of pottery fragments in D2 indicates transport of sediment from the shallower harbor area, indicating deposition by return flow of the tsunami. In a final phase, the tsunamite was buried and the remaining scour depression was infilled by sand deposited by longshore currents and storm activity on the shelf
By using stratigraphic, micropaleontological (foraminifera), and geochemical (Sr isotopes) analyses of the ancient harbor deposits we can establish a late first to early second century A.D. date for the destruction of the harbor. This destruction occurred earlier, was more rapid and widespread than previously proposed, and was probably caused by seismic activity. In 21 B.C., King Herod the Great, ruler of Judea, built an all-weather harbor at Caesarea (Fig. 1)

The harbor was completed in 10 B.C. and was described by Josephus Flavius (a Jewish historian) in A.D. 72-75 (Holum et al., 1988)

On the basis of archaeological evidence, the remains of the Herodian harbor are believed to be submerged 6 m below the water surface

Here we present new geoarchaeological evidence from the harbor sediments that conclusively determines the destruction of the harbor in the late first to early second century A.D., and documents a limited rejuvenation of the harbor in the fourth to early sixth centuries A.D. The first to second century A.D. basal rubble unit (L4) was found on the carbonate cemented sandstone bedrock (locally known as kurkar) and was characteristic of a high-energy water deposit (Fig. 2). The rubble was framework supported with little surrounding matrix and composed mainly of cobble-sized material, which was well rounded, heavily encrusted (e.g., bryozoans, calcareous algae), and bored (Lithophaga lithophaga, Cliona) on its upper surface. The rubble had variable lithologies including basalts, gabbros, and dolomites, all of which are absent on the Israeli coastal plain and were likely transported to the site as ship ballast (probably from Cyprus). The surrounding matrix was composed of shell material (mainly Glycymeris insubricus), pebbles, and coarse sand. The pottery sherds found in this unit were well rounded, encrusted, and dated to the first to second century A.D. The date for this unit and its sedimentological characters clearly records the existence of high-energy conditions within the inner harbor about 100–200 yr after the harbor was built. This evidence of high-energy water conditions indicates that the outer harbor breakwaters must have been severely degraded by this time to allow waves to penetrate the inner confines of the harbor (Fig. 3, A and B).

Indication of the rapid destruction of the outer harbor breakwaters toward the end of the first century A.D. is derived from additional data recovered from the outer harbor. In the 1993 season, a late first century A.D. shipwreck was found on the southern submerged breakwater. The merchant ship was carrying lead ingots that were narrowly dated to A.D. 83–96 based on the inscription "IMP.DOMIT.CAESARIS.AUG.GER." which refers to the Roman Emperor Domitianus (Raban, 1999). The wreck was positioned on the harbor breakwater, indicating that this portion of the structure must have been submerged to allow a ship to run up and founder on top (Raban, 1999; Fig. 3B). Because Josephus praised the harbor in grand terms and referred to it as a functioning entity around A.D. 75–79, and yet portions of the breakwater were submerged by A.D. 83–96, we conclude that there was a rapid deterioration and submergence of the harbor, probably through seismic activity


The submergence of the outer harbor breakwaters at the end of the first century A.D. could have also been due to seismic liquefaction of the sediment. Excavations have shown that the harbor breakwaters were constructed on well-sorted sand that could have undergone liquefaction with seismic activity. In many instances the caissons are tilted (15°–20° from horizontal; Raban et al., 1999a) and at different elevations, which could be due to differential settling (area K; Fig. 1). However, the tilting could also be due to undercutting by current scour from large-scale storms (or tsunamis) and not exclusively seismic activity.

Our data from the inner harbor cannot definitively ascribe the destruction of the harbor at the end of the first century A.D. to a seismic event, although some of the data support this conclusion. However, regardless of the exact mechanism, our sedimentological evidence from the inner harbor and the remains of the late first century A.D. shipwreck indicate that the submergence of the outer breakwater occurred early in the life of the harbor and was more rapid and extensive than previously thought


At the very deepest spot where the airlift penetrated, beneath huge stone blocks which teetered precariously above the divers' heads, was uncovered a large wooden beam. Beneath its protective cover the divers found the only whole amphora of our dig. This proved to be a second century Roman vessel. The fact that it was found under the tumbled beam and masonry would indicate that these things were catapulted into the sea at the same time. Since there is a strong earthquake recorded in the area of Caesarea in the year A.D. 130 [JW: this refers to the Eusebius Mystery Quake - could also be the Incense Road Quake], it may possibly be that the harbor installations of Herod were destroyed at that time.

Other finds recovered from the original bottom, now under fifteen feet of sand, included numerous sherds of second century amphorae, corroded bronze coins, ivory hairpins, colorful bits of glass and other objects of the Roman period


This date could possibly narrow further. Goodman-Tchernov and Austin (2015:451) also discussed part of a harbor tower which was apparently constructed atop an artificial island. Remains of this tower, uncovered during excavations in the 1990s, were found to be lying horizontally, indicating that the tower had collapsed. Goodman-Tchernov and Austin (2015:451) report that artifacts “found around the base of the toppled tower,” were “within the typical scouring areas where debris is regularly trapped in harbor entrances.” According to Goodman-Tchernov and Austin (2015:451), the artifacts post-date the 1st century CE, with “the earliest coin found aged at 144 CE.” If these artifacts are in fact part of tsunamigenic deposits that were formed at more or less the same time that the tower collapsed, this would refine the time window for the Event 2 tsunami to early 70s CE – 144 CE.

Old Notes by JW

Using ceramics, Reinhardt and Raban (1999) dated a high energy subsea deposit inside the harbor at Caesarea to the late 1st / early 2nd century CE. This, along with other supporting evidence, indicated that the outer harbor breakwater must have subsided around this time. They attributed the subsidence to seismic activity.

L4 — Destruction Phase

The first to second century A.D. basal rubble unit (L4) was found on the carbonate cemented sandstone bedrock (locally known as kurkar) and was characteristic of a high-energy water deposit (Fig. 2). The rubble was framework supported with little surrounding matrix and composed mainly of cobble-sized material, which was well rounded, heavily encrusted (e.g., bryozoans, calcareous algae), and bored (Lithophaga lithophaga, Cliona) on its upper surface. The rubble had variable lithologies including basalts, gabbros, and dolomites, all of which are absent on the Israeli coastal plain and were likely transported to the site as ship ballast (probably from Cyprus). The surrounding matrix was composed of shell material (mainly Glycymeris insubricus), pebbles, and coarse sand. The pottery sherds found in this unit were well rounded, encrusted, and dated to the first to second century A.D. The date for this unit and its sedimentological characters clearly records the existence of high-energy conditions within the inner harbor about 100-200 yr after the harbor was built. This evidence of high-energy water conditions indicates that the outer harbor breakwaters must have been severely degraded by this time to allow waves to penetrate the inner confines of the harbor (Fig. 3, A and B).

Indication of the rapid destruction of the outer harbor breakwaters toward the end of the first century A.D. is derived from additional data recovered from the outer harbor. In the 1993 season, a late first century A.D. shipwreck was found on the southern submerged breakwater. The merchant ship was carrying lead ingots that were narrowly dated to A.D. 83-96 based on the inscription "IMP.DOMIT.CAESARIS.AUG.GER." which refers to the Roman Emperor Domitianus (Raban, 1999). The wreck was positioned on the harbor breakwater, indicating that this portion of the structure must have been submerged to allow a ship to run-up and founder on top (Raban, 1999; Fig. 3B). Because Josephus praised the harbor in grand terms and referred to it as a functioning entity around A.D. 75-79, and yet portions of the breakwater were submerged by A.D. 83-96, we conclude that there was a rapid deterioration and submergence of the harbor, probably through seismic activity.
Later they suggested that the subsidence had a neotectonic origin.
Evidence for neotectonic subsidence of the harbor has been reinforced by separate geologic studies (stratigraphic analysis of boreholes, Neev et al., 1987; seismic surveys, Mart and Perecman, 1996) that recognize faults in the shallow continental shelf and in the proximity of Caesarea; one fault extends across the central portion of the harbor. However, obtaining precise dates for movement along the faults is difficult. Archaeological evidence of submergence can be useful for dating and determining the magnitude of these events: however, at Caesarea the evidence is not always clear.
Neotectonic subsidence is unlikely. As pointed out by Dey et al(2014), the coastline appears to have been stable for the past ~2000 years (Fig. 2) with sea level fluctuating no more than ± 50 cm, no pronounced vertical displacement of the city's Roman aqueduct (Raban, 1989:18-21), and harbor constructions completed directly on bedrock showing no signs of subsidence. However, Reinhardt and Raban (1999) considered more realistic possibilities for submergence of harbor installations such as seismically induced liquefaction, storm scour, and tsunamis.
The submergence of the outer harbor break-waters at the end of the first century A.D. could have also been due to seismic liquefaction of the sediment. Excavations have shown that the harbor breakwaters were constructed on well-sorted sand that could have undergone liquefaction with seismic activity. In many instances the caissons are tilted (15°-20° from horizontal; Raban et al., 1999a) and at different elevations, which could be due to differential settling (area K; Fig. 1). However, the tilting could also be due to undercutting by current scour from large-scale storms (or tsunamis) and not exclusively seismic activity. Our data from the inner harbor cannot definitively ascribe the destruction of the harbor at the end of the first century A.D. to a seismic event, although some of the data support this conclusion. However, regardless of the exact mechanism, our sedimentological evidence from the inner harbor and the remains of the late first century A.D. shipwreck indicate that the submergence of the outer breakwater occurred early in the life of the harbor and was more rapid and extensive than previously thought.
Goodman-Tchernov and Austin (2015) examined and dated cores taken seaward of the harbor and identified 2 tsunamite deposits (see Tsunamogenic Evidence) including one which dates to to the 1st-2nd century CE. Although, it is tempting to correlate the 1st-2nd century CE tsunamite deposits of Goodman-Tchernov and Austin (2015) to the L4 destruction phase identified in the harbor ( Reinhardt and Raban, 1999), the chronologies presented by Goodman-Tchernov and Austin (2015) suffer from some imprecision due to the usual paucity of dating material that one encounters with cores. Further, the harbor subsidence and breakwater degradation dated by Reinhardt and Raban (1999) may not have been caused by seismic activity. If it was related to seismic activity, the early 2nd century CE Incense Road Quake is a better candidate than the 115 CE Trajan Quake because it would have produced higher intensities in Caesarea.

Fritsch and Ben-Dor (1961) reported the following from an early underwater exploration of Caesarea's harbor.
At the very deepest spot where the airlift penetrated, beneath huge stone blocks which teetered precariously above the divers' heads, was uncovered a large wooden beam. Beneath its protective cover the divers found the only whole amphora of our dig. This proved to be a second century Roman vessel. The fact that it was found under the tumbled beam and masonry would indicate that these things were catapulted into the sea at the same time. Since there is a strong earthquake recorded in the area of Caesarea in the year A.D. 130 [JW: this refers to the Eusebius Mystery Quake - could also be Incense Road Quake], it may possibly be that the harbor installations of Herod were destroyed at that time.

Other finds recovered from the original bottom, now under fifteen feet of sand, included numerous sherds of second century amphorae, corroded bronze coins, ivory hairpins, colorful bits of glass and other objects of the Roman period. Two objects were of special significance. One was a small lead baling seal with a standing winged figure. It has a pinpoint hole near its center, and a rather deep, depressed line on the back of it, as though made by a wire.3

The other object was probably the most important thing discovered at Caesarea this past summer. It was a small commemorative coin or medal made of an unidentified alloy, about the size of a ten-cent piece, with two holes drilled through it as if it might have been worn as a pendant. Upon the face of it there is the representation of the entrance to a port flanked by round stone towers surmounted by statues. Arches border the jetty on either side of the towers, and two sailing vessels are about to enter the harbor. Two letters, KA, may well be the abbreviation for the word Caesarea. The other side of the coin shows the figure of a male with a long beard and a tail like a dolphin, with a mace-like object in his hand. Coin experts who have seen this piece agree that it is unique, and that it undoubtedly depicts the ancient port of Caesarea. It may have been issued to commemorate some important occasion at Caesarea in the first or second century A.D.
Footnotes

3. This object may be an amulet, the winged figure representing Horus, the Egyptian sun god who wards off lurking evils. Cf. E.A.W. Budge, Amulets and Superstitions (London, 1930) 166. A close examination of the original piece, however, leads one to conclude that it is a baling seal.

Steele et al. (2024)

Abstract

The construction of harbours along high energy nearshore environments, which commonly include the emplacement of hard structures both as central features (e.g., piers, jetties) as well as protective measures (e.g., wave breakers, coastal armouring), can alter coastlines in a multitude of ways. These include reconfiguring the coast’s morphology, introducing or redistributing exogenous and endogenous materials, and changing localized environmental substrate and structural conditions; and, as a result, impact the associated ecological communities. With growing coastal populations and associated coastal development, concerns over the long-term consequences of such projects are of global interest. Caesarea Maritima, a large-scale, artificially constructed ancient harbour built between 21 and 10 BCE, provides a rare opportunity to address these impacts and investigate its fingerprint on the landscape over 2000 years. To approach this, representative sediment samples were isolated and analyzed from two sediment cores (C1, C2), an excavated trench (W), and a sample of ancient harbour construction material (aeolianite sandstone and hydraulic concrete; COF). Geochemical (Itrax μXRF, magnetic susceptibility) and foraminifera analyses were conducted and results from both methods were statistically grouped into significantly similar clusters. Results demonstrated the increased presence of aeolianite-associated elemental contributions only after the construction of Caesarea as well as in particularly high concentrations following previously proposed tsunami events, during which shallower and deeper materials would have been transported and redeposited. The foraminifera data shows the appearance and eventual abundance dominance of Pararotalia calcariformata as an indicator of coastal hardening. Results suggest that they are an especially well-suited species to demonstrate changing environmental conditions existing today. In previous studies, this species was mistakenly presented as a recent Lessepsian arrival from the Red Sea, when in fact it has had a long history as an epiphyte living on hardgrounds in the Mediterranean and co-existencing with humans and their harbour-building habits. Specimens of P. calcariformata, therefore, are useful indicators for the timing of harbour construction at Caesarea and may be used as rapid and cost-effective biostratigraphic indicators on sandy nearshore coastline in future geoarchaeological studies. This has implications for future studies along the Israeli coast, including both paleoenvironmental and modern ecological assessments.

1. Introduction

Ancient harbour sediments and stratigraphy are often studied because they contain evidence of past environmental change including climate, sea-level, and anthropogenic activity (Blackman, 1982a, 1982b; Kamoun et al., 2019, 2020, 2021; Marriner and Morhange, 2007; Reinhardt et al., 1994; Riddick et al., 2021; Riddick et al., 2022a, 2022b; Salomon et al., 2016). The analysis and interpretation of environmental proxies (e.g., microfossils, geochemistry, lithology, etc.) can be more straightforward in cases of shoreline progradation, where relative sea-level changes, siltation, and/or high input of river sediments have resulted in landlocked marine structures (i.e., within lagoons or estuaries). Sediments in these cases often record transitions from marine to more brackish/freshwater conditions associated with construction of harbour structures and/or natural barriers that are identifiable through changes in microfossil assemblages, sediment grain size and geochemistry, and other environmental indicators (Amato et al., 2020; Finkler et al., 2018; Kamoun et al., 2022; Pint et al., 2015; Stock et al., 2013, 2016).

The environmental evolution (i.e., site formation) of ancient harbour sites on high-energy, sandy coasts is more challenging to assess. Sediments from within a harbour basin can record geoarchaeological information (e.g., ancient harbour parasequences, changes in microfossil assemblages, archaeological material, etc.; Marriner and Morhange, 2006; Reinhardt et al., 1994; Riddick et al., 2021; Riddick et al., 2022a, 2022b); however, correlating stratigraphy in a harbour region can often be hindered by sediment reworking with waves and storms and by the absence of significant lithological changes in the sandy stratigraphy, with the exception of tsunamis or other large storm events (Goodman-Tchernov et al., 2009). The emplacement of ancient harbours (i.e., artificial hard substrates) on naturally soft-bottomed, sandy shorelines, significantly alters the local seascape resulting in sediment erosion and accumulation as well as the formation of a hard and stable substrate (Leys and Mulligan, 2011).

Past research on ancient harbour sediments (e.g., Marriner et al., 2005; Reinhardt et al., 1994; Salomon et al., 2016) has focused on analysis of harbour muds, recognizable by their muddy-appearance (finer particle size distribution; ‘muds’; Hohlfelder, 2000), higher organic content, and increased concentrations of artifacts. In those studies, various bioindicator proxies, in particular gastropods, molluscs, ostracods, and foraminifera, were used to recognize harbour stratigraphy and related changing conditions connected to construction, destruction, and/or functionality (Kamoun et al., 2019, 2020, 2021; Marriner et al., 2005; Reinhardt and Raban, 1999). Amongst marine biomarkers, benthic foraminifera are especially popular as environmental proxies due to their known ecological preferences and tolerances, their rapid response to environmental change, and their durability in the sediment record over time (Holbourn et al., 2013; Murray, 2014). Generally, research to date on ancient harbour assemblage changes were linked to the increased presence of fine-grainedsediment preferring species (e.g., Bolivinids) as well as shifting relative abundances of the more dominant brackish Ammonia species (Goodman et al., 2009; Kamoun et al., 2022; Marriner et al., 2005; Reinhardt et al., 1994; Reinhardt and Raban, 1999). This agrees with the more general understanding that substrate is a major controlling factor in foraminifera assemblages (Langer, 1988, 1993). We hypothesize here that while the harbour muds introduce new conditions for a changing benthic foraminifera assemblage, so too can the increased presence of hard materials related to harbour construction and coastal development. These hard surfaces are especially influential on attached, epiphytic taxa. These taxa, therefore, will record a response to the introduction of artificial hard substrates in the sandy, high-energy settings seaward and beyond the protected environments of the harbour, and can act as biostratigraphic indicators of pre- and post- harbour sediments, a concept that has not previously been tested or applied.

Previously collected samples from an excavated trench area (W; Reinhardt et al., 2006), two sediment cores (C1, C2; Goodman-Tchernov et al., 2009), and a piece of harbour mole material retrieved during underwater excavations in 1999 (COF; Reinhardt et al., 2001) were included in this study (Fig. 1). Seven samples (5-cm intervals) were available from W (− 11.4 to − 13.4 m below sea level (mbsl), ~0.60 km from the coast; Reinhardt et al., 2006). Nineteen samples (1-cm intervals) from the upper 126 cm were available from C1 (233 cm in length, 15.5 mbsl, ~0.82 km from the coast) and 14 samples (1-cm intervals) were available from C2 (174 cm in length, 20.3 mbsl, ~1.25 km from the coast; Goodman-Tchernov et al., 2009). Radiocarbon and/or pottery dating methods were previously conducted on W, C1, and C2 samples. See Goodman-Tchernov et al. (2009) and Reinhardt et al. (2006) for further details on dating methods used. Geochemical ((μXRF, magnetic susceptibility) and foraminifera methods were applied here. The use of benthic foraminifera as biostratigraphic indicators to help correlate sediments in archaeological contexts is still a developing area of research (McGowran, 2009). The application of benthic foraminifera in this manner will be useful for future geoarchaeological studies as a rapid and cost-effective method for correlating sediments across an ancient harbour site, especially in high energy sandy shoreface settings. Results also have implications for understanding sediment transport in and around coastal structures, as well as for modern studies involving the monitoring and/or predicting of ecological changes in response to coastal anthropogenic activity.

2. Background

2.1. Regional geology and geochemistry

The Israeli Mediterranean coastline (Fig. 1) is mostly characterized by unconsolidated sands and Pleistocene aeolian sandstone ridges (‘kurkar’). These thick calcareous-cemented sand beds accumulated cyclically between thin layers of iron-rich paleosols (‘hamra’) and currently run parallel to the coast, both on and offshore (Almagor et al., 2000; Ronen, 2018). The southern two thirds of the coastline are characterized by sandy beaches (Emery and Neev, 1960). The tidal range is relatively small along the coast (0.4 during spring tides, 0.15 m during neap tides; Golik and Rosen, 1999). Offshore sediments are transported through two different types of nearshore currents: an inner edge of the general offshore current (which moves northwards, counterclockwise along the eastern end of the Mediterranean; Fig. 1), and a wave-induced longshore current (Emery and Neev, 1960; Goldsmith and Golik, 1980; Klein et al., 2007; Schattner et al., 2015). The largest waves in this region generally approach the coast from a WNW direction, which results in a longshore current to the northeast along the curved southern shoreline (Fig. 1). Where these waves approach parallel or at an angle opposite to that of the southern coast (e.g., some areas towards the northern coastline of Israel), a small, southward longshore current is produced (Emery and Neev, 1960; Goldsmith and Golik, 1980; Zviely et al., 2007). Located towards the northern extent of the Nile Littoral Cell, offshore sediments near Caesarea are predominantly transported from the south through this wave-induced longshore current (Emery and Neev, 1960; Goldsmith and Golik, 1980; Golik, 1993, 1997; Katz and Crouvi, 2018; Schattner et al., 2015; Zviely et al., 2007). Prior to the construction of the Aswan Dam in the 1960s, approximately 100,000 m3/yr of clastic sediments reach the coasts of Caesarea, largely sourced from Central Africa and the Ethiopian Highlands (Nir, 1984). These sediments are dominated by silica (quartz), alumina, and trivalent iron oxides (e.g., aluminosilicates) with minor amounts of heavy minerals (Goldsmith et al., 2001; Inman and Jenkins, 1984; Nir, 1984). The majority of heavy minerals include hornblende, augite, and epidotes, as well as minor amounts of resistant (e.g., zircon, tourmaline, rutile) and metamorphic minerals (e.g., sillimanite, staurolite, kyanite; Stanley, 1989). Local sources (i.e., eroded kurkar, onshore sediments, marine productivity) contribute some calcareous sediment to the nearshore environment (Goldsmith et al., 2001; Inman and Jenkins, 1984; Nir, 1984; see Supplementary Data 1 for more details on dominant minerals, compositions, and sources). Sand-sized sediment extends 3–5 km from the shore to water depths of ~25 m, while increasing amounts of silt and clay (mainly smectite, with minor kaolinite and illite) are found further offshore in slightly deeper water (30–50 m depths; Almagor et al., 2000; Emery and Neev, 1960; Nir, 1984; Sandler and Herut, 2000). The siliclastic sands, which characterize most of the nearshore, transition into more carbonate-rich sediments with higher instances of rocky substrates north of Haifa Bay (Almagor et al., 2000; Avnaim-Katav et al., 2015; Hyams-Kaphzan et al., 2014; Nir, 1984).

2.2. Historical and geological background on installations at Caesarea

The historical site of Caesarea Maritima is located ~40 km south of Haifa, on the Israeli Mediterranean coast (34◦53.5′E 32◦30.5′N). Over six decades of research have provided details on the construction and deterioration of its harbour, also referred to as Sebastos, the largest artificial open-sea Mediterranean harbour of its time (Brandon, 2008; Hohlfelder et al., 2007). The harbour was constructed between 21 and 10 BCE using local kurkar and imported volcanic material (Vola et al., 2011; Votruba, 2007). Local kurkar is characterized by well-sorted quartz with calcite and minor amounts of feldspar, biotite, heavy minerals (e.g., hornblende, augite, zircon, rutile, tourmaline, magnetite, garnet, etc.), and allochems (Wasserman, 2021). Volcanic material has been used in concrete by the Romans since the 2nd century BCE (Oleson, 1988), often sourced from the Bay of Naples Neopolitan Yellow Tuff (NYT) deposits. Pozzolanic tuff-ash from this region was used in hydraulic concrete to form the breakwaters and foundations for harbour moles at Sebastos (Vola et al., 2011; Votruba, 2007). The mixture of lime, pozzolana, and aggregate provided a strong concrete that could set underwater. At Caesarea, the dominant coarse aggregates in the hydraulic concrete are kurkar sandstone and limestone (4 mm–20 cm in size; Vola et al., 2011). The mortar contains high proportions of pozzolanic material (yellow brown tuff ash/aggregates, lava fragments) with dominant minerals identified as sanidine, clinopyroxene, analcime, and phillipsite. The cementitious binding matrix contains similar material (calcite, tobermorite, ettringite, Calcium–Aluminum–Silic ate–Hydrate) and was likely produced by the reaction between powdered pozzolanic material, lime, and seawater. Non-pozzolanic portions include white lime clasts, kurkar sandstone aggregates, ceramics, and wood fragments, with dominant minerals identified as tobermorite, quartz, illite, anthophyllite, ettringite, halite, bassanite, and sjogrenite (Vola et al., 2011; Supplementary Data 1).

The chronology of Sebastos has been well-studied, with detailed research into the timing of deterioration and harbour use throughout antiquity (Boyce et al., 2009; Galili et al., 2021; Goodman-Tchernov and Austin, 2015; Hohlfelder, 2000; Raban, 1992, 1996; Reinhardt et al., 2006; Reinhardt and Raban, 1999). The location of Sebastos on a highenergy, mostly sandy coastline, as well as the previously established chronology of harbour construction, makes this an ideal site to assess the use of benthic foraminifera as biostratigraphic indicators of anthropogenic structure emplacement. The distribution of benthic foraminifera along the Israeli coast has been well-documented, providing a strong basis for interpreting trends within sediment samples offshore of Caesarea.

2.3. Benthic foraminifera of the Israeli Mediterranean coastline

Introduction

Studies of both living and dead benthic foraminifera assemblages along the Israeli coast of the Mediterranean Sea indicate that substrate type (often linked to bathymetry), food availability, and seasonality are the main factors controlling the distribution of species (Arieli et al., 2011; Avnaim-Katav et al., 2013, 2015, 2016a, 2020, 2021; HyamsKaphzan et al., 2008, 2009, 2014). Certain taxa such as Ammonia parkinsoniana and Buccella spp. are highly abundant in the shallow (3–20 m), sandy nearshore settings. Others including Ammonia inflata, Ammonia tepida, Elphidium spp., Porosononion spp., and miliolids are often observed in slightly deeper (20–40 m), silty to clayey environments further offshore on the inner Israeli shelf (Avnaim-Katav et al., 2013, 2015, 2016a, 2016b, 2017, 2020, 2021; Hyams-Kaphzan et al., 2008, 2009, 2014). Epiphytic taxa, which live on roots, stems, and leaves of plants (Langer, 1993; Langer et al., 1998), are highly associated with the micro- and macroalgal-covered hard substrates along the Israeli Mediterranean coast, especially the carbonate-rich rocky settings along the northern coast (Arieli et al., 2011; Avnaim-Katav et al., 2013, 2015, 2021; Hyams-Kaphzan et al., 2008, 2014). Coralline red algae (e.g., Galaxuara rugosa and Jania rubens) are highly abundant along the Israeli coast, along with other types of red (e.g., Centroceras sp., Ceramium sp., Bangia sp., Halopteris scoparia, Laurencia sp., Neosiphonia sp., and Polysiphonia sp.), brown (e.g., Dictyora sp., and Ectocarpus sp.), and green algae (Codium sp. and Ulva sp.; Arieli et al., 2011; Bresler and Yanko, 1995a, 1995b; Emery and Neev, 1960; Hyams-Kaphzan et al., 2014; Schmidt et al., 2015). Some of the most common epiphytic foraminifera taxa observed here include Amphistegina lobifera, Lachlanella spp., Heterostegina depressa, Pararotalia calcariformata, Rosalina globularis, Textularia agglutinans, and Tretomphalus bulloides, (Arieli et al., 2011; Hyams-Kaphzan et al., 2014). Many of these larger, symbiont bearing foraminifera are widely assumed to be more recently introduced Lessepsian species, a term used to describe Red Sea/Indian Ocean tropical species that have arrived after the construction of the Suez Canal (1869 CE). While some have been linked genetically and morphologically with their Red Sea communities, others, such as P. calcariformata (Schmidt et al., 2015; Stulpinaite et al., 2020) still have not

2.3.1. Pararotalia calcariformata

Specimens of P. calcariformata McCulloch, 1977 were originally identified as P. spinigera (Le Calvez, 1949) on the Israeli coast, in particular within dated, stratigraphically discreet underwater archaeological excavations and geological collections (e.g., in Reinhardt et al. (1994, 2003), Reinhardt and Raban (1999)). Schmidt et al. (2015)’s initial error occurred when they mistook the date of the first publication that reported them on this coastline for the timing of their first observation (see reference to Reinhardt et al., 1994 in introduction of Schmidt et al., 2015). In fact, the P. calcariformata in that study were firmly positioned in sediments dating to at least 1500 years ago. P. calcariformata is a well-documented epiphyte, found in highest abundances near hard substrates (up to 96% in shallow rocky habitats) of the Israeli coast (Hyams-Kaphzan et al., 2014; Reinhardt et al., 2003), usually living on calcareous algae and other seaweeds (e.g., Jania rubens, Halimeda, Sargassum, Cystoseira; Arieli et al., 2011; Bresler and Yanko, 1995a, 1995b; Emery and Neev, 1960; Schmidt et al., 2015, 2018). It is observed less frequently (up to 20% relative abundances) in shallow, soft-bottomed, sandy sediments (Avnaim-Katav et al., 2017, 2020; Hyams-Kaphzan et al., 2008, 2009). Recent work on this species explores its microalgal symbionts (Schmidt et al., 2015, 2018) and its high heat tolerance (Schmidt et al., 2016; Titelboim et al., 2016, 2017). These studies predict that warming sea temperatures will play a role in expanding populations of P. calcariformata along the Mediterranean.

4. Results

4.1 Core lithology and chronology

W is described in Reinhardt et al. (2006), while C1 and C2 are described in Goodman-Tchernov et al. (2009). W (~2 m of excavated sediment) contains two main shell layers: (i) a poorly sorted mix of Glycymeris spp. and pebbles from ~107–165 cm, with convex-up oriented fragments in the top portion, and (ii) a heterogeneous layer of shell fragments, ship ballast, and pottery shards from ~39–59 cm. The intervening units consist of massive, homogeneous, medium-grained sand with isolated articulated and fragmented bivalve shells and/or pebbles. The upper ~0–39 cm also contains thin layers of shells and pebbles (Fig. 2). The upper 126 cm of C1 contains two shell layers: (i) a poorly sorted mix of Glycymeris spp. and pebbles, with fragments of worn pottery from 85 to 94 cm, and (ii) poorly sorted, convex-up oriented Glycymeris spp. and pebbles from 28 to 42 cm. The intervening units are massive, tan/grey, fine-grained sand, some with isolated bivalves and/or pebbles (Fig. 2). C2 (174 cm) similarly contains two shell layers: (i) framework supported, convex-up oriented Glycymeris spp. fragments from 132 to 138 cm, and (ii) convex-up oriented Glycymeris spp. fragments from 29 to 43 cm. The intervening units are massive, tan/ Gy, fine-grained sand with some silt and isolated bivalves.

The chronology of W, C1, and C2 has been previously described (Goodman-Tchernov et al., 2009; Reinhardt et al., 2006), and units have been correlated to age ranges (radiocarbon and pottery; Table 1) and identified events (i.e., tsunami deposits; Fig. 2). W, C1, and C2 were found to capture similar event layers dating to ~1492–100 BCE (preharbour), 92 BCE–308 CE (containing the 115 CE Roman tsunami event), 238 BCE–329 CE, 400–800 CE (containing the 551/749 CE Late Byzantine/Early Islamic tsunami events), and 800 CE–present (Table 1, Fig. 2).

4.2. Geochemical results

Elemental (μXRF) results are shown in Fig. 3 and Supplementary Data 2. Average counts of Zr increase upcore in each sampling area, with uppermost values ~2–3 times higher than those at the base (~700–1000 compared to 200–400; Fig. 3, Supplementary Data 2). Ca is highly variable throughout all sampling areas, with some peaks up to 1.7× higher (~300,000) in shell layers than in sandy samples. Counts of Si remain relatively high (~17,000) throughout time, with some decreases up to 1.5–2.5× lower in shell layers. Average Ti values are variable through time (~6000) with some spikes up to 2× higher at the top and bottom of C1 and surrounding the bottom shell layer of C2. Fe follows similar trends to Ti, with values ~2× higher near the top and bottom of C1 and the darker sandy sediments of C2 (161–123 cm) compared to the intervening sandy samples (counts of ~6000–7000). Counts of Sr remain quite constant throughout all sampling areas over time (~2000), with a slight increasing trend in the upper portions of C1 and C2 (values up to ~1.3×; Fig. 3, Supplementary Data 2).

Ratio results of Zr + Ti/Ca and Zr + Ti/Si are variable throughout time in W (values 0.02–0.04 and 0.20–0.34) and C2 (0.03–0.08 and 0.4–1.4), especially within tsunami event layers, though results show no clear increasing/decreasing trends over time. In C1, these ratios show a distinct increasing trend through the upper half of the core (Zr + Ti/Ca: from 0.02 up to 0.06; Zr + Ti/Si: 0.3 up to 0.7). Sr/Ca values remain relatively consistent in all coring areas (~0.10), with minor variation surrounding shell layers (Fig. 3, Supplementary Data 2).

Sample COF shows distinct variation in elemental composition between kurkar and hydraulic concrete (Fig. 4). On average, counts of Zr and Ti are over 10× higher in the hydraulic concrete than the kurkar. Counts of Fe are also higher in the hydraulic concrete by a factor of ~8. Ca shows the opposite trend, with counts 5× higher in the kurkar than the hydraulic concrete. Counts of Si were variable throughout both materials but were slightly higher in the hydraulic concrete. Sr peaked in the kurkar and decreased moving into the hydraulic concrete, with some variability associated with the aggregate material (Fig. 4). Ratio results for Zr + Ti/Ca are ~94× higher in the hydraulic concrete than in the kurkar, while Zr + Ti/Si values are almost 2× higher. Sr/Ca are ~4× higher in the hydraulic concrete than in the kurkar (Fig. 4).

The cluster analysis of W, C1, C2, and COF results displayed seven superclusters (SC1–SC7; Fig. 5). SC1 and SC2 are highly similar, though SC1 contains relatively higher counts of Si and lower counts of Ti and Fe than SC2. SC2 appears more frequently in samples from the upper halves of the cores, while SC1 appears more frequently in deeper and older contexts (Fig. 5). SC3 and SC4 appear only in the ash-rich portion of COF. SC5 is highly similar to SC1, with some peaks in Zr and Sr compared to SC1, appears mainly in the sandy units of cores, and reflects the general sedimentary background of the coast. SC6 contains very few samples and is analogous to SC5. SC7 is characterized by relatively high counts of Ca and Si and is predominantly associated with the kurkar portion of COF, with some samples from tsunami layers of W and C1, and with the uppermost sand layers of C2 (Fig. 5).

The magnetic susceptibility of sediments remains relatively low throughout all samples (Table 2). Aside from a peak (27.8 × 10− 6 SI) at the top of C1, values range between 5.2 and 10.4 × 10− 6 SI in C1, 8.9–13.5 × 10− 6 SI in C2, and 2.6–7.1 × 10− 6 SI in W, with no distinct trends over time (Table 2).

4.3. Foraminifera results

Thirteen statistically significant foraminifera taxa were identified across W, C1, and C2, and the cluster analysis revealed four significant (au >95%) assemblages (A1, A2, A3, A4; Figs. 6 and 7, Supplementary Data 3). The NMDS showed that the four assemblages overlapped, especially A2, A3, and A4, suggesting that samples within these assemblages were quite similar despite grouping distinctly (Fig. 6). A1 contains only samples from the tops of W and C1. This assemblage is dominated by A. parkinsoniana (~3–21%), P. calcariformata (~43–74%), and miliolids (~13–20%; Fig. 7; Supplementary Data 3). A2 contains samples from the sand and lower shell layers of W, as well as the lower shell layer of C2. Assemblage A2 is dominated by A. parkinsoniana (~46–70%), Porosononion spp. (~0–19%), and miliolids (~12–22%). Assemblage A3 contains samples from the top and middle shell layers of C1, as well as the top sand, middle sand and shell layers of C2. Dominant specimens within this assemblage include A. parkinsoniana (~4–23%), P. calcariformata (~0–19%), Porosononion spp. (~2–11%), and miliolids (~42–69%). A4 contains samples from the middle sand layers of C1, as well as the middle sand, and bottom shell and sand layers of C2 (Fig. 7). This assemblage is dominated by A. parkinsoniana (~20–44%), P. calcariformata (~0–21%), Porosononion spp. (~1–17%), miliolids (~21–46%), and planktonic foraminifera (~0–15%; Fig. 7; Supplementary Data 3).

Increasing abundances of P. calcariformata (Supplementary Data 4) over time were observed in all three sampling locations. In W, this species was relatively abundant (0.38–51.74%) and was observed in all samples except for 150–155 cm. Pararotalia calcariformata was observed at highest abundances (0.91–73.68%) in the top 0–71 cm of C1, and at lowest abundances (6.25–20.79%) in the top 0–42 cm of C2. This species was also observed at relatively low abundances towards the bottom of C2 (1.19% at 126–127 cm and 0.71% at 131–137 cm).

5. Discussion

5.1. Pre-harbour nearshore sediment composition and distribution

Prior to the construction of Sebastos, the shoreline at Caesarea was characterized by a soft-bottomed, unconsolidated sandy beach overlying regional kurkar ridges (Fig. 8; Almagor et al., 2000; Reinhardt et al., 1994; Ronen, 2018). This is reflected in both foraminifera and geochemistry results in C2 and the lower two thirds of C1 and W (Figs. 3, 7). Biofacies A2, A3, and A4 (pre-harbour), characterized by relatively higher proportions of A. parkinsoniana, miliolids, and Porsononion spp., are consistent with Reinhardt et al. (1994)’s pre-harbour foraminiferal faunal results (Fig. 7). These taxa are typically associated with shallow and mid-depth (3–20 m, and 20–40 m) Nilotic sands and silty–clayey sediments of the Israeli inner shelf (Avnaim-Katav et al., 2013, 2015, 2016b, 2017, 2019, 2020, 2021; Hyams-Kaphzan et al., 2008, 2009, 2014). The minor presence of P. calcariformata at the bottom of C2 and in pre-harbour sediments is associated with the coarse shell unit of the Santorini tsunami (Goodman-Tchernov et al., 2009). This event transported shallow marine sediment offshore including the epiphytic P. calcariformata, likely from the kurkar hard grounds (Reinhardt et al., 2003).

The relative consistency in average counts of Ca, Si, Ti, and Fe through time within the sandy units of each of the three sampling areas suggests that there is virtually no difference in abundance of these elements in pre-and post-harbour sediments (Fig. 3; Supplementary Data 2). This reflects the pre-harbour (and post-harbour) regional geology (local carbonate-rich kurkar), marine productivity (e.g., shells), and Nile sediment sources (aluminosilicate minerals within the shoreline’s sands, silts, and clays, as well as the minor amounts of heavy minerals; Supplementary Data 1 and 2). In pre-harbour sediments, slight variations in counts for Ca, Si, Ti, and Fe (increases or decreases in average counts by factors of ~1.1–1.8) predominantly surround the Santorini event (Fig. 3). This is expected, as high-energy events typically result in abnormal deposition (e.g., shell material, rip-up clasts, archaeological material, beach-derived pebbles) that would be reflected in geochemical results (Goodman-Tchernov et al., 2009; Kamoun et al., 2021).

The cluster analysis of elemental data shows very slight variation in sediment composition based on sample location, especially between W and C2 (Fig. 5), which could be the result of natural nearshore sediment transport patterns (Almagor et al., 2000; Emery and Neev, 1960; Quick, 1991). Onshore-offshore sediment transport is mainly wind-driven and is controlled by several forces related to incoming waves, sediment size, and beach slope (Quick, 1991). During summer months on the Israeli coast, relatively calm northwesterly winds generate waves and currents that cause sands to move shoreward (Almagor et al., 2000; Emery and Neev, 1960; Quick, 1991). During winter months, strong southwesterly storm winds result in offshore sand transport. Since waves break at an angle to the Israeli shoreline, onshore-offshore sediment movement occurs in a slightly oblique direction, with net transport northwards (Almagor et al., 2000; Emery and Neev, 1960). Because the amount of sediment carried through longshore currents decreases northward, and beach accretion along the coasts largely does not take place, researchers have concluded that sediment must be lost (e.g., moved seawards or blown landwards) along the way (Almagor et al., 2000; Emery and Neev, 1960). Through a study on sand balance, Almagor et al. (2000) estimated that roughly 450,000 m2 /year of sediment is lost to seaward escape between Gaza and Haifa. Sands are actively deposited within a gently sloping (0.5–0.8◦) nearshore zone extending 3–5 km offshore (~40 m water depth), near the easternmost drowned kurkar ridge (Almagor et al., 2000). Sands that escape past this point are mixed with increasing amounts of silts and clays that accumulate on a relatively flat seabed (Almagor et al., 2000; Nir, 1984; Sandler and Herut, 2000). All sampled areas in this study are within this zone of active sedimentation, though each site was sampled at different depths and distances from shore, so we would expect to see some natural variation in composition.

5.2. Post-harbour nearshore sediment composition and distribution

5.2.1. Geochemical indicators of harbour deterioration

The chemofacies results reflect coastal development, mainly through SC1, SC2, and SC7. SC1 is a coarser grain version of sediments that cluster with SC2. SC1 replaces SC2 in the upper portion of all three cores. The reduction in clays (indicated by Ti) and increase in silica within this shift in chemofacies suggests slight grain coarsening over time, while the increase in Ba indicates an increase in productivity. This slight shift over time may represent natural changes in sediment sources (e.g., variations in White and Blue Nile sediments, terrestrial inputs, etc.) and/or anthropogenic influence (Kalman et al., 2022). SC7, which relates to the kurkar component of sediments (Figs. 4 and 5), appears much more frequently post-harbour and with tsunami influence. Kurkar was heavily used in the construction of the harbour (Vola et al., 2011; Votruba, 2007), and tsunamis transported and deposited this material further offshore. The slight presence of SC7 in the Santorini event layer (C1, Fig. 5) reflects this process occurring pre-harbour, with natural kurkar deposits along the coast.

Heavy minerals including zircon and rutile exist in Israeli sands in minor abundances (Lin et al., 1974; Pomerancblum, 1966; Stanley, 1989), as demonstrated by the presence of Zr (~300) and Ti (~5000) throughout the pre-harbour sediment samples. These minerals come from several sources including Nile sediments, local onshore terrains, aeolian dust, and reworked sedimentary bedrock (Supplementary Data 1). On the Israeli coast and other high-energy, sandy shorelines, heavy minerals become naturally concentrated due to mechanical sorting (Stanley, 1989). Through waves and currents, denser mineral grains typically settle out of suspension and accumulate at the bottom of the swash zone while lighter grains are carried back towards shore to the wave zone (Dinis and Soares, 2007; Hou et al., 2017). Abundances along the Israeli coast are still relatively low (~0.1–0.5%; Lin et al., 1974). Differences along the coast due to varying local sources of sediment (e. g., nearby wadis/rivers) are minor, and any significant changes in heavy mineral abundances would require vast amounts of sand inputs (Boenigk and Neber, 2005). The increase in Zr + Ti/Ca and Zr + Ti/Si values from pre- to post-harbour sediments (by factors of 3 and 2.3, respectively), and the observed increasing trend within post-harbour sediments is therefore not likely to be caused by natural sources and is most likely related to harbour deterioration. Although Zr was not reported in Vola et al. (2011)’s bulk chemical and petrographic analysis of Sebastos concrete and TiO2 was only a minor component of the mortar (0.2–0.3%), we observed distinctly higher values of Zr and Ti throughout the hydraulic concrete portion of COF (avg Zr + Ti/Ca: 0.187; avg. Zr + Ti/Si: 2.02) compared to the kurkar portion (avg Zr + Ti/Ca: 0.002; avg. Zr + Ti/Si: 1.27). This suggests the presence of trace amounts of (or mineral impurities including) Zr and Ti within the aggregate material and the fine-grained matrix of the concrete. Our results suggest that the foreign volcanic material contains a much larger proportion of heavy minerals compared to local kurkar sources of sediment.

Magnetic susceptibility results are comparable to previous studies of Caesarea. Boyce et al. (2004, 2009) found a range of 0.1 to 8.7 × 10− 5 SI for harbour bottom sands and muds, which is similar to most sediments in this study (2.6 to 13.5 × 10− 5 SI; Table 2). The relatively extreme value observed at the top of C1 (27.8 × 10− 5 SI) more closely aligns with values of pozzolana (22.7 to 175.2 × 10− 6 SI; Boyce et al., 2004) than the quartz sands and harbour muds. The presence of eroded hamra material (κ = 88.0 × 10− 5 SI; Boyce et al., 2004), eroded igneous or metamorphic ballast stones (κ ≥90 to >200 × 10− 5 SI; Boyce et al., 2009) or eroded clay fragments (κ = 133.7 × 10− 5 SI; Boyce et al., 2004) could also be influencing the higher value at the top of C1. Any of these sources could indicate increased presence of harbour material in recent offshore sediments (Fig. 8). Additional sediment samples, especially throughout the top portion of W and C1 would help to confirm the observed trends in magnetic susceptibility.

Observable changes in heavy minerals following harbour construction occur within sediments between the Santorini event (1630–1550 BCE) and the Late Byzantine/Early Islamic tsunami events (551/749 CE); however, correlating a more precise estimated depth for the timing of harbour construction remains a challenge solely with the XRF results (Fig. 3). The benthic foraminifera results, however, can be used to further refine these estimates.

5.2.2. Epiphytic foraminifera as biostratigraphic indicators of artificial substrate chang

lations is evident in A1, at the tops of W and C1 (Fig. 7). This assemblage contains distinctly higher abundances of P. calcariformata (Fig. 9; Supplementary Data 4), a common epiphytic species usually found in association with calcareous algae in rocky areas of the Israeli inner shelf (Arieli et al., 2011; Bresler and Yanko, 1995a, 1995b; Emery and Neev, 1960; Hyams-Kaphzan et al., 2014; Reinhardt et al., 2003; Schmidt et al., 2015, 2018). As harbour structures progressively over time, increasing amounts of cryptic spaces would have formed, providing increasing amounts of surface area for algal or seagrass growth. Ratio values for Sr/Ca do not seem to vary significantly over time, suggesting a continuous presence of aragonitic organisms (shells, calcareous algae, etc.). In C1, values slightly increase over time following a drop during the Late Byzantine tsunami event (Fig. 3) which may be related to an increase in calcareous algal growth on harbour ruins. Increased sample resolution would help to confirm this trend. Hard substrates (i.e., submerged harbour structures) with algal growth are optimal settings for P. calcariformata, and increased populations of this species after harbour construction are recorded in all three sampling areas. After death, these specimens would have detached from the algalcovered harbour and been transported to the nearby sediments by onshore-offshore transport mechanisms discussed above (Section 5.1), especially by strong storm waves during winter months (Fig. 8; Almagor et al., 2000; Quick, 1991). Higher abundances are recorded in deposits close to the site (i.e., W and C1), though their presence is still observed 800 m from the harbour structures (C2; Fig. 7).

Other epiphytic species are present in low abundances throughout the sampling areas (Fig. 9) but do not show significant trends over time, likely due to their preferred habitats. Textularia bocki and T. bulloides are more often associated with the northern coast of Israel beyond the Nile littoral cell; T. bocki is usually found in deeper (30–100 m), silty-clayey sediments (Avnaim-Katav et al., 2013, 2015, 2020, 2021), while T. bulloides has been observed in shallow rocky areas surrounding Haifa (Arieli et al., 2011; Hyams-Kaphzan et al., 2014). These foraminifera results demonstrate the importance of understanding the distribution 800 m from the harbour structures (C2; Fig. 7).

and habitat preferences for the taxa of a specific region when considering using epiphytic species as indicators of substrate changes. The benthic foraminifera result here, especially P. calcariformata, provide information to help further correlate the timing of harbour construction within C1 and C2 (Fig. 7). Results also confirm that P. calcariformata is not a recent invasive species as previously thought (Schmidt et al., 2015; Stulpinaite et al., 2020). In all three cores, P. calcariformata was observed in sediments follow construction of Sebastos harbour, and in C2, specimens were observed in two samples dating to the Santorini event bed (1630–1550 BCE; Fig. 7; Supplementary Data 3). This supports Reinhardt et al. (1994)’s observations of this species in historical sediments, as well as Stulpinaite et al. (2020)’s verdict that this species is native to the Mediterranean, and suggests that it has been living on the eastern Mediterranean coast since around the Late Bronze Age. The results here indicate that substrate conditions are an important habitat control on P. calcariformata. This has not been adequately considered in recent studies that explore the distribution of this species. Schmidt et al. (2015) briefly mention that there is some substrate control on this species, though estimations of range expansions have been based on solar radiance, turbidity, and temperature even though samples in the studies were all associated with hard substrates (Schmidt et al., 2015, 2016, 2018; Titelboim et al., 2016, 2017). Similarly, Yanko et al. (1994) discussed sea temperature as a key factor influencing the higher abundance of this species in proximity to the site of Hadera; however, they failed to consider the presence of extensive hard grounds with algal coverage at the power station. The results here suggest that nearby substrates, including artificial structures such as harbour or pilings, should be considered in future research involving the distribution of benthic foraminifera along the Mediterranean.

5.3. Implications for sediment transport and site formation

Based on the distribution pattern of P. calcariformata observed here, alternative applications of epiphytic foraminifera along high energy sandy shoreface settings could include long-term studies on sediment dynamics (e.g., tracking sediment transport in and around coastal structures, the extent of onshore-offshore sand movement, tracking the extent of the storm weather wave base over time, etc.). Understanding sediment dynamics is important for coast engineering projects (Leys and Mulligan, 2011). Fluorescent tracers are often used to assess onshoreoffshore sediment transport and sediment accumulation patterns around marinas; however, these methods only provide data spanning several months (Klein et al., 2007). Because the main source of P. calcariformata in high energy sandy shoreface settings is the submerged surface of harbour structures (anthropogenic hard grounds), these microfossils can provide long-term data on onshore-offshore transport trends, sediment accumulation patterns around the harbour itself, and on longshore transport patterns along the coast. This could enhance studies using fluorescent tracers as it provides more long-term information.

Sediment reworking (vertical movement) during storms and tsunamis plays a major role in the stratigraphic distribution of P. calcariformata. As discussed in Reinhardt and Raban (2016), the sands within the active sediment layer are regularly reworked. Storms and tsunami waves often cause scour and erosion of the seabed as well as removal of fine sand particles from around larger, heavier, rubble material. This results in vertical transport of the rubble material downwards, producing an “armoured” layer that resists further erosion (Reinhardt and Raban, 2016). Foraminifera and larger sand particles within the active sediment layer would be reworked through this winnowing action as well, with larger storms having a greater effect on transport, especially closer to shore. This mechanism of sediment reworking would occur offshore up to the storm weather wave base, though to a lesser extent. Significant abundances of P. calcariformata would likely not be transported much further offshore and therefore provide recognition of the storm wave base through time. Our three cores show this trend with P. calcariformata, found at ~0–30 cm at 20 m water depth (C2, ~0–60 cm at 15 m (C1), and ~ 0–150 cm at 10 m (W). This shows that shallow marine sands are being transported at least ~2 km offshore with larger storms. The presence/absence of P. calcariformata provides an efficient low-cost method for determining pre- and post-harbour sediment which can be difficult to identify in these sandy high-energy settings, especially if the sands contain no material culture (e.g., pottery).

6. Conclusions

This study shows that anthropogenically altered coastlines, in particular hard coastal structures, leave a fingerprint on their environment not only through changed elemental composition but also biomarkers such as epiphytic foraminifera. These changes are present and recognizable in the ancient harbour context at Caesarea Maritima. There, an excavated trench area (W), two sediment cores (C1, C2), and a piece of harbour material (COF) were analyzed through elemental (μXRF, magnetic susceptibility) and/or foraminifera analyses. Heavy mineral proxies (Zr + Ti/Ca, Zr + Ti/Si, magnetic susceptibility) indicate that particulate matter offshore, originating as part of or due to the harbour structures have increased since the construction of the harbour ~2000 years ago. Benthic foraminifera assemblages A3, and A4 reflect the shallow and mid-depth (3–40 m) sandy to sandy silt substrates that characterized much of the nearshore Israeli coast prior to harbour construction. Post-construction assemblages (e.g., A1, A2) include increasing abundances of epiphytic species, especially P. calcariformata. This species was successfully used as a biostratigraphic indicator for the timing of harbour construction as it is present in significant abundances only after the harbour and city are established around 2000 years ago. Pararotalia calcariformata was recently erroneously assumed to be a recent invasive species, increasing in population along the Israeli coast following the opening of the Suez Canal in 1869. Results from this study suggest that this species is endemic to the Israeli coast, observed here in coastal sediments pre-dating the canal opening by thousands of years. The recent attention on this species as a marker of changing environments and climate, suggested due to its current proliferation along the coastline and heat tolerance, is not an error and is worthy of continued study. We add here, in agreement, that it is a harbinger of anthropogenic change and thrives on the increased coarsening and hardening of the coastline and shallow shelf, outcomes of post-Aswan Dam decreases in the delivery of fine sediments (Kalman et al., 2022), coastal armouring, and general development.

This study demonstrates that the analysis of epiphytic foraminifera, such as P. calcariformata, can be implemented as rapid and cost-effective biostratigraphic indicators in future geoarchaeological studies at Caesarea or in similar settings elsewhere. The results have implications for the role of P. calcariformata in modern studies of benthic foraminifera on the eastern Mediterranean, mainly that it is not a recent invader, but rather a species that has thrived on the changing substrate conditions created by human activity for millennia.

Summary by ChatGPT

Steele et al. (2024) investigate how the emplacement of artificial structures, particularly King Herod’s harbor (Sebastos) at Caesarea, altered sedimentary and biological signals offshore. A significant portion of their analysis deals with depositional events linked to extreme marine inundations, including tsunami activity.

Geoarchaeological context from core C2 includes the identification of a coarse-shell unit that the authors associate with the Santorini eruption tsunami (ca. 1600 BCE). This tsunami event is known from previous studies such as Goodman-Tchernov et al. (2009) and is used here to explain anomalous faunal distributions at the base of the core— especially the offshore transport of typically shallow epiphytic foraminifera like *Pararotalia calcariformata*.

Additionally, Steele et al. note a decline in Sr/Ca ratios and changes in foraminiferal abundance that correspond to the stratigraphic levels associated with later events, including the 749 CE tsunami, reinforcing a broader regional chronology discussed by Goodman-Tchernov & Austin (2015).

Overall, Steele et al. highlight how high-resolution microfaunal and geochemical analysis can provide biostratigraphic markers for tsunamogenic and anthropogenic events. Their findings contribute to a growing recognition of tsunami-induced sedimentary structures within archaeological harbor sequences.

The study by Steele et al. (2024) also investigates sedimentary and biological indicators of environmental change in and around the artificial harbour of Caesarea Maritima, with particular relevance to identifying tsunamogenic signatures. The authors analyze cores (C1, C2), an excavated trench (W), and construction materials, applying μXRF geochemistry, magnetic susceptibility, and foraminiferal assemblages. A key observation is the presence of aeolianite-associated elemental signatures in post-construction strata—especially within discrete intervals interpreted as high-energy redeposition layers. These layers correspond stratigraphically to tsunami events proposed in prior research, in which deeper and shallower sediment materials were mixed and redistributed.

The authors interpret spikes in concentrations of specific sedimentological and geochemical markers in tandem with faunal changes as indicative of tsunamogenic transport. *Pararotalia calcariformata*, a foraminifer associated with hard substrate habitats, appears in anomalously high abundance following harbour construction and is found within layers suspected to have been disturbed by tsunami backwash or overwash. Its detachment from hard substrates and lateral offshore transport supports the interpretation of rapid, high-energy events. These observations provide both an anthropogenic signal (harbour construction) and a paleotsunami signal (event-related reworking), offering dual insight into ancient coastal dynamics.

The study suggests that both geochemical anomalies and faunal redistribution can be used to fingerprint tsunami impacts on coastal sediment records and that Caesarea offers a unique case study where tsunamogenic effects can be separated from long-term anthropogenic sediment reconfiguration.

Goodman-Tchernov and Austin (2015)

Abstract

Modern observations have shown that harbors are especially vulnerable to the effects of tsunamis, both due to their position on the coastline and the tendency for tsunamigenic eddy production within enclosed harbor basins. Presumably, this was as much the case in the past as in the present. The Roman-era mega-harbor Caesarea Maritima, which is today submerged in some parts up to 5 m below sea level, is an ideal research site for understanding these impacts. Over the past three decades, archeologists, geologists and historians have searched for the cause of the rapid demise of this harbor, turning to explanations ranging from offshore faults, seismic disturbances, general failure and deterioration, to liquefaction and settling on unconsolidated sands. While tsunamis are recorded repeatedly in the Eastern Mediterranean historical record, it has only been in the past decade that physical evidence directly attributed to tsunamigenic sediments along the Israeli coastline near Caesarea has been documented. To date, deposits from at least three tsunami events that impacted the harbor have been identified in sediment cores, coastal exposures and archeological trenches, but no laterally continuous picture has been produced. In this study, using a dense offshore survey produced by a high-resolution subbottom profiler, shallowly buried sediment horizons offshore of Caesarea produce distinctive reflectors that correlate with the tsunamigenic stratigraphic sequence identified in cores and excavations. These surface structure maps allow for a laterally extensive reconstruction of these distinctive deposits. The results have led to the following conclusions and interpretations:
  1. multiple offshore tsunamigenic horizons at Caesarea can be recognized
  2. individual tsunamigenic event horizons result in distinctive and unique surface morphologies that elucidate tsunami-based channeling/backflow processes
  3. these backwash channels can be used to assess the general physical condition of the harbor at the time of each tsunami occurrence, ultimately revealing major differences between the state of the harbor following earlier events (i.e., 2nd c. CE) vs. later events (6–8th c. CE)
We conclude that the combined acoustic-sampling approach is an effective way to document the interaction of tsunamis with harbor complexes and adjacent coastlines over millennia.

I. Introduction and background

1.1. Evidence for tsunami impacts on coastal morphology and associated structures

Coastal morphology, including adjacent landforms, artificial structures, and coastal-fringing natural features (i.e., extensive coral reefs, mangroves, e.g., Baird et al., 2005; Fernando et al., 2005; Kunkel et al., 2006; Giri et al., 2008) can all influence the impact of tsunami wave flow (Hon et al., 2007; Sugawara et al., 2012). As the inundating wave breaches the coastline, natural and man-made obstacles that obstruct or impede the wave’s force can lead to channeling and variable flow, both as the wave advances inland and retreats seawards. Such energy redistribution is also evident in affected rivers or artificial channels, in which tsunami flow will continue inland to distances far exceeding that of uninterrupted portions of the coastline (e.g., Crete 1956, Bruins et al., 2008; Okal et al., 2009; northern Japan 2011, Mori et al., 2011; Goto, 2011a; Chile 2010, Fritz et al., 2011). The tsunami return/outflow is even more influenced by the presence of structures, and therefore is typically characterized by channeling (Umitsu et al., 2007; Feldens et al., 2009), which can result in shore-perpendicular bathymetric and topographic features (Atwater et al., 2010). In Sumatra following the 2004 tsunami, evidence of such complex back-flow included filled channels, boulders moved into deeper water, movement of sand into previously silty areas, and man-made rubble immediately seaward of the shoreline (Feldens et al., 2009; Goto, 2011b). Similarly, in northern Japan following the Tohoku-Oki earthquake in 2011, canals and road features often corresponded with variations in tsunami inundation heights along the Sendai Plain.

Amongst the range of coastal structures that interact with tsunamis, harbors have been identified as locations of acute magnification and flow intensification in both simulations and field studies (Raichlen, 1966; Synolakis and Okal, 2005; Lynett et al., 2012). For example, during the 2004 tsunami, at the Port of Salalah, Oman, strong currents produced inside the harbor caused a 285 m ship to break away from its moorings and beach on a nearby sandbar after spinning and drifting for hours (Okal et al., 2006). At Port Blair, India, harbor structure damage included movement or complete collapse of the jetties (Kaushik and Jain, 2007). Examples are also available for the far-field effects of tsunamis, where harbors have been damaged while adjacent coastlines experience little inundation. One such harbor is located in Crescent City, CA; this site was damaged repeatedly following both near-field events, such as Alaska 1964, as well as far-field tsunamis, such as those generated from seismic events in 2006 (Kuril Islands) and in 2011 (Tohoku-Oki) (Griffin, 1984; Horrillo et al., 2008; Kowalik et al., 2008; Wilson et al., 2013). Widespread documentation of ships originally moored in harbors that have been displaced inland and/or damaged along the adjacent coastline during tsunamis are common; this phenomenon includes relatively small events, such as the tsunami following the 1999 Izmit earthquake in Turkey, with varying reports of wave heights, but with possible localized heights of ~6 m (Rothaus et al., 2004).

Following a tsunami, a variety of characteristic markers can be left behind, both on the shallow sea bottom and on shore, including massive debris fields, sheets of sand, muddy film, and/or eroded surfaces, amongst a list of over thirty-two published indicators (e.g., Goff et al., 2012). Depending on the specific surface conditions of the impacted coastline, e.g., surficial sediment types, strandline morphology and available unconsolidated debris, coastal zone bathymetry can be altered as contents carried within the tsunami flow drop out as the wave energy dissipates (Jaffe et al., 2012). Inland, tsunami-based deposits are generally characterized by landward thinning (Morton et al., 2007), unless interrupted by some limiting structure or topography.

The patterns of tsunami deposits and bathymetric forms created by these waves can be informative regarding the character of the affected coastline and adjacent offshore areas (Richmond et al., 2012). In northern Japan, for example, artificial channels and a highway constructed on the Sendai Plain before the 2011 Tohoku-Oki earthquake influenced the distribution of tsunami-deposited sediments and wave run-up heights (Sugawara et al., 2012), relative to the distribution of known preexisting tsunami deposits. Recognizing and mapping tsunami-related features from historical events should inform us as to the state of both natural and artificial structures on a coastline which were affected by these tsunamis, including the influences of the back-wash phase of sedimentation. In this study, the ancient harbor of Caesarea Maritima, on the eastern Mediterranean coast of Israel (Fig. 1), is presented as an ideal site to consider this tsunami-impact phenomenon, and how and whether the physical evidence for such recurring impacts might be preserved over two millennia.

1.2. Caesarea Maritima: the ancient harbor, its deterioration and demise, and recent tsunami research

When King Herod had the city of Caesarea built on the coastline of what is now Israel between 25 BCE and 9/10 BCE, he applied Roman city planning, organization and building techniques, including the costly installation of a state-of-the-art, artificial mega-harbor (Holum et al., 1988; Hohlfelder, 1988, 1996; Raban, 2009; Votruba, 2007; Raban, 2008; Fig. 1). The natural environment afforded little protection or anchorage, with the exception of periodic, remnant, exposed ridges of eolianite sandstone (locally referred to as ‘kurkar’) roughly paralleling the coastline immediately offshore. These bedrock structures are exposed and eroded lithified dunes 135,000–45,000 years old (Sivan and Porat, 2004). The harbor was constructed on portions of this bedrock and extended seaward onto unconsolidated Nile River–derived sands (Goldsmith and Golik, 1980; Neev et al., 1987; Stanley, 1989; Zviely et al., 2007), with the use of man-made foundations. Roman engineers succeeded in this task by building wooden frameworks (‘caissons’) on land, then towing them into position where they were submerged, filling them with hydraulic cement, and ultimately finishing them with above-water superstructures. Fields of large cobbles (less than 20 cm diameter) were emplaced beneath the caissons (Raban, 2008), presumably to give them added stability against erosion and undermining, suggesting that the engineers of the time were aware of the inherent risks for constructing directly on unconsolidated sandy sediments. These caissons were arranged in rows to produce the spinal walls of the harbor, completing the entire project in less than 15 years (Brandon, 1996). This efficient approach to harbor construction continues to be used today. For example, ‘Mulberry I’ and “Mulberry II”, created by the allies during WWII in preparation for the D-Day landings, were also artificial islands constructed in a similar manner for the purpose of providing supplies and reinforcements until an established harbor could be secured (Stanford, 1951; Ryan, 1959; Bettwy, 2015).

Descriptions made ~70 CE by historian Flavius Josephus describe a fully functional imperial mega-harbor, exceeding the size of most contemporaneous Mediterranean harbors (Raban, 2008). Josephus explicitly describes the expense of and investment made in the harbor's construction. Excavations have since supported these grandiose statements, revealing bulk raw building materials that traveled long journeys before arriving in Caesarea (Votruba, 2007). For example, chemical analysis of the volcanic ash (‘pozzolana’) used for producing the fast-drying hydraulic cement shows that the ash was brought from Vesuvius (Brandon, 1996; Hohlfelder et al., 2007), while the underlying cobble and rubble beds beneath the cement-filled caissons show non-local mineralogies common to Turkey, Cyprus, and parts of Greece. The wood used for the caisson frames, as was common practice in shipbuilding of the time, came from the cedar forests of Lebanon (Votruba, 2007).

However, despite the significant investment and durability of the cement used in the construction process (Jackson et al., 2012), the overall state of the harbor had significantly deteriorated by the end of the 2nd century CE, and probably even earlier, according to radiocarbon-dated sedimentological evidence showing a shift from a low-energy, harbor environment to an open-water exposed, unprotected environment during that period (Reinhardt and Raban, 1999; Reinhardt et al., 1994). Throughout the 1990s, the generally accepted presumption arising from these studies was that the harbor experienced its demise due to some combination of earthquake-related liquefaction, with some credence also given to the possibility of related tsunami, though without clear markers then to support such a hypothesis.

Caesarea harbor phases, from initial construction to the present, have been reconstructed using sedimentological, geophysical (i.e., magnetometry), and archaeological surveys (Reinhardt et al., 1994; Reinhardt and Raban, 1999, 2008; Boyce et al., 2009). The most recent summary (Reinhardt and Raban, 2008) suggests six such phases, summarized as follows:
  1. Initial construction, 1st century CE
  2. Destruction, 1–2nd century CE
  3. Unprotected (exposed to open sea; no intact harbor features), 3–4th century CE
  4. Natural/unimproved harbor, 4–6th century CE
  5. Sand infilling, 6th century CE
  6. Renovation/destruction, 6–11th century CE
Unfortunately, the foregoing summary remains vague regarding causation, as it predates later findings (Goodman-Tchernov et al., 2009) that bring to light evidence for tsunami events in both the Byzantine (4–6th c. CE) and Early Islamic (7th–8th c. CE) periods, as well as confirming an earlier suggestion of another 2nd century CE wave-based event (Reinhardt et al., 2006).

Previous geophysical research on the Caesarea Maritima harbor has included both seismic and magnetic surveys (Mart and Perecman, 1996; Boyce et al., 2004, 2009). Boyce et al. (2004) conducted a magnetic survey with the aim of determining the feasibility of using magnetic signatures to map and define the concrete installations of the harbor, as the pozzolana cement used by the Romans was iron-rich. Although the high resistivity of the kurkar bedrock proved to be challenging, the overall form of the foundations of the harbor, particularly the individual caisson forms, was discernible. Due to the significant difference between the near-coastal harbor features, which remain at their correct elevation relative to sea level, and offshore harbor features, which are now submerged up to 5 m depth, earlier work had suggested that movement along a shore-parallel fault, which became active following construction of the harbor, could be responsible for the modern elevation change (Mart and Perecman, 1996). As a result, for many years afterward, theoretical north–south trending fault lines remained on maps of Caesarea. However, after failed attempts to recognize these features in the field through additional geophysical mapping, along with jet-probe surveys of the sediments with associated seafloor excavations (Raban, 2008), such structures are now rarely included. Instead, the observed coast-parallel offset in elevation is now presumed to relate more directly to the classic challenges faced when constructing directly on bedrock versus adjacent (offshore) unconsolidated sediments. Areas of the harbor constructed seaward of the firm kurkar bedrock foundation were likely more susceptible to liquefaction, undercutting, scouring and erosion, promoting subsidence of harbor features farther offshore, whether by storms, earthquakes, or tsunamis.

Historical evidence for tsunamis in the eastern Mediterranean supports a minimum of 21 events, three referring to the city of Caesarea directly (115 CE, 551 CE and 1202 CE; Shalem, 1956; Amiran et al., 1994). Archaeologists have been aware of these events for decades (see discussion in Dey et al., 2014), but they have lacked the comparative tools or reference data to ascribe particular deposits (onshore or offshore) to tsunami-derived causes. As a result, alternative explanations for these seemingly anomalous deposits found in archaeological sites have been put forward. For example, laterally extensive shell beds encountered in terrestrial excavations in Caesarea, which could be evidence of tsunamigenic origin, have been previously ascribed to be the result either of dredging activities or as construction fill (Neev and Emery, 1989). Tsunami sedimentological research has also advanced, particularly in response to the destructive tsunamis of Sumatra 2004, Java 2009, Chile 2010 and Tohoku-Oki 2011 (e.g., Szczuciński, 2011; Goff et al., 2012; Pilarczyk and Reinhardt, 2012; Pilarczyk et al., 2012; Goto et al., 2014). As a result, there is now an extensive, robust body of comparative data for interpreting and understanding historical, prehistorical and paleo-tsunamigenic deposits (e.g., Bourgeois et al., 1988; Goff et al., 2012), which did not exist a decade ago.

This increase in knowledge has led to the recognition of more such tsunamigenic deposits worldwide, both in the archaeological and geological records (e.g., Pareschi et al., 2007; Vött et al., 2009; de Martini et al., 2010; Yawsangratt et al., 2011; Marco et al., 2014, but see also criticism of this approach in Galili et al., 2008; Morhange et al., 2014). However, despite this increased awareness, the number of tsunamigenic sedimentological deposits documented from the Levantine Sea region, and other parts of the Eastern Mediterranean, still only begins to approach the number of events recorded in the written record (Papadopoulos et al., 2014), suggesting that discovery of these deposits in this historically important part of the world remains incomplete.

Research on the demise of Caesarea's harbor (Reinhardt et al., 1994; Reinhardt and Raban, 1999) agrees generally that the timing of initial major deterioration had occurred at least by the end of the 2nd century CE (see also Raban, 1992; Raban, 1995; Reinhardt and Raban, 2008; see Hohlfelder, 2000, for alternate timing). Evidence to support the role of tsunamis in this initial damage takes the form of laterally extensive sedimentary horizons with interpreted tsunamigenic characteristics (details follow below) recorded offshore, as well as reviews of archaeological reports demonstrating the presence of corresponding deposits on land (Reinhardt et al., 2006; Goodman-Tchernov et al., 2009; Dey and Goodman-Tchernov, 2010; Dey et al., 2014).

Reinhardt et al. (2006) have characterized a tsunami deposit, found in an excavation trench (Area ‘W’, see Fig. 1C) outside of the ancient harbor, based on the presence of imbricated allochthonous shells (predominately Glycymeris violescens), with radiometric ages (1st c. BCE to 2nd c. CE) corresponding with a historically documented tsunami event at 115 CE (Shalem, 1956). Other defining characteristics of this deposit include an erosional basal contact, and mixing of included clast sizes. Goodman-Tchernov et al. (2009) have also investigated the lateral extent of this reported horizon, and identified its continuation, as well as the presence of additional interpreted but distinct tsunami horizons, based on the same criteria and an additional seven tsunami-related indicators: micropaleontological assemblage, fining-upward sequence, tilted marine installations, larger standard deviation of particle size distributions (relative to typical background), out-of-place household items, rip-up harbor mud clasts, and rafted terrestrial organic material. Reports from terrestrial archaeological excavation reports pre-dating the Reinhardt et al. (2006) initial recognition of these tsunami deposits were also revisited by Goodman-Tchernov et al. (2009) to determine whether other horizons containing possible tsunami-related inclusions had been described in the literature but not interpreted as such. Their realization was that a wide range of distinctive stratigraphic evidence for tsunami-related deposits was present. Other sorts of interpretations had included construction fill or dredging refuse dump, but these were refuted in light of new tsunami characterizations (Dey and Goodman, 2010; Dey et al., 2014). In this paper, regional high-resolution seismic profiling offshore the harbor mouth of Caesarea is combined with ongoing marine archaeological investigations to show the regional impact of multiple tsunamis on both this harbor and the adjacent coastline over the past two millennia
.

1.3. Offshore tsunami deposits

Generally speaking, the near offshore environment has not been heavily mined for tsunami evidence. While tsunami-related studies have increased exponentially in the past decade, there are far fewer studies that present shallow offshore finds. In their summary of the state of research in paleotsunami deposits Rhodes et al. (2006) asked, “Does a record of paleotsunamis exist in the near offshore stratigraphic record?”. By that time, Vandenbergh et al. (2003) had demonstrated the presence of shallow offshore deposits using both geophysical survey and coring in NW Java, Indonesia and Abrantes et al. (2005) described events correlatable to sediment core horizons in Lisbon, Portugal. Since then, a few studies of past and recent tsunami events and modeling have answered Rhodes' question in the affirmative as well. Some examples beyond the work in Caesarea (Reinhardt et al., 2006; Goodman-Tchernov et al., 2009, Dey and Goodman 2010, Dey et al. 2014) include cores collected from Augusta Bay, Italy (de Martini et al., 2010; Smedile et al., 2012), offshore boulders mapped in western Banda Aceh, Indonesia (Paris et al., 2009), Weiss and Bahlburg's (2006) modeling predictions suggesting the presence of deposits in the shallow offshore. The near offshore environment is still more poorly understood relative to terrestrial coastal areas.

4. Discussion

The interpretation of three sub-seafloor reflectors mapped offshore of Caesarea (Fig. 3) conclude with the presence of distinctive and unique coastal structural configurations at the time of past tsunami events. The mapping suggests regionally significant impedance contrasts, that were interpreted here as marking the last/uppermost expression of known tsunami deposits previously sampled, analyzed and interpreted on this margin (Fig. 4). In all cases, we assume, and this is supported by modern studies elsewhere (Paris et al., 2009), that immediately following any tsunami, complex processes of alteration and erosion occur, particularly in depths exposed to storm activity and other coastal processes (e.g., long shore transport). In this part of the Mediterranean, these tsunami deposits, or what part of them is preserved after exposure to later storm and long-shore transport effects, are buried under Nile River–derived sands. Therefore, we suspect that the reflector maps of the two subsurface reflectors (Fig. 6B, C) does not give a reading of what the sea bottom looked like immediately following the tsunami, but at the time of the tsunamite’s eventual burial, which could be a matter of decades or more. Therefore, the apparent drainage features we observe are probably only preserved remnants of tsunami backwash features which, at the time of their formation, would have been even more distinctive and pronounced, as is true in modern analogues (Bahlburg and Spiske, 2012; Feldens et al., 2009; Hori et al., 2007; Paris et al., 2009). Each event has a unique signature that relates to the state of the coastline and the structures present at that time.

The deepest reflector, ‘C’ (Fig. 3B), which is associated here with what is left of the Santorini-age tsunamite, is not sufficiently preserved offshore Caesarea to identify except in topographic lows in the kurkar topography (Fig. 3B), and in deeper water. The unaltered coastline in this area is high-energy, with little natural protection, which is one of the reasons that specialized engineering methods were required to create the Caesarea harbor. Therefore, prior to the harbor’s construction, at the time of the Santorini-age event (Fig. 4), tsunami deposits in shallow water would not have had a good chance for preservation due to their exposure to the open sea, but were more likely redistributed and transported during storms; we also see such storm-related redistribution today. In contrast, later events following the construction of the harbor have a greater chance of preserving due to the more protected nature within the harbor area, even if only in relative terms, from the full force of incoming storms. This is observable today during storms in which the waves are noticeably attenuated within the semi-protected harbor bay, despite the harbor’s generally dilapidated condition. Sedimentological evidence clearly shows the presence of the Santorini horizon in water depths > 10 m (Fig. 4). In area ‘W’ (Fig. 1C; 4, upper right) the stratigraphic sequence includes a major hiatus (~3 kyr of missing sediment), which includes the level at which the Santorini horizon would have been expected. We expect such a hiatus in area W, as it is located just outside the harbor entrance, and would have experienced focused outgoing flow capable of substantial erosion and scouring during the back-channeling phase of a tsunami. In addition, because harbors are known to intensify the effects of tsunamis, any Santorini-aged tsunami deposits in shallow water that survived until the construction of the harbor would have been vulnerable to further erasure following the first of the post-harbor construction tsunami events (Fig. 4).

Reflector B’s surface morphology includes a main channel complex that corresponds approximately with the position of the harbor entrance (Fig. 6C). Because Caesarea’s harbor is believed to have been in good condition at the time of the 2nd century tsunami, the incoming wave must have encountered an intact and standing outer harbor mole, which would have forced abrupt shoaling of the incoming wave, scouring deeply the area immediately outside the harbor, while also breaching the tops of man-made features. Incoming wave inundation must also have run up within the harbor, as well as along the coastline north and south. However, during subsequent retreat of the wave, that outflowing water would have concentrated through the harbor mouth, between the reinforced moles (Fig. 2), preferentially scouring and eroding the region immediately outside the harbor entrance and depositing larger deposits farther offshore, as is evident in the ~80 cm 2nd century deposit in Area W (Reinhardt et al., 2006). Estimating the velocity of the flow exiting the harbor mouth during the 115 CE event is possible, because archaeological evidence exists for the movement and toppling of an artificial island that stood at the harbor entrance at that time (Raban, 2008). During excavations there in the late 1990s, concrete was exposed and a vertical contact between cement layers of different fabrics was recorded. These cement layers are a remnant of the construction process, during which different cement mixes were used at different phases of filling the wooden caissons (Brandon, 1996, Hohfelder et al., 2007). At the time of construction, after the cement cured, the different concretes layers lay horizontal upon one another; therefore, any shift from the original position at construction can be identified due to the offset of that horizontal contact. In the case of the tower, the near-vertical contact indicates at least a 90° shift of the caisson after the harbor was completed. It was also observed that no wood was preserved on any outer surface of the island, whereas typically protected, unexposed sides of the caissons included some preserved wood, again suggesting that all sides of the island, which was essentially once a wood-faced concrete cube, had been exposed on all sides fully to the elements at some point of time, a situation only possible with the turning of the caisson. Artifacts found around the base of the toppled tower post-date the 1st century CE, with the earliest coin found aged at 144 CE. These deposits are not beneath the tower, but rather along the edges of the tower within the typical scouring areas where debris is regularly trapped in harbor entrances. Excavations did not tunnel fully below the towers due to safety concerns. Such artifacts might provide an age maximum for the timing of the tower’s collapse, so the observed damage best correlates with the historic tsunami a few decades earlier in 115 CE. As the minimum size of this island was at least 25 m³, and as its concrete has an estimated minimum density of ~2400 kg/m³, its estimated weight should exceed 60 metric tons. Toppling such an island would have required significant force, and is analogous to damage that has been recorded to concrete harbor structures recently during the 2011 Tohoku-Oki tsunami in northern Japan events (Fig. 7, Ewing et al., 2013).

We hypothesize that the shallower subsurface reflector ‘A’ is the buried surface formed by backflow associated with the 8th century CE (possibly 749 CE) tsunami; this surface could also represent a composite with the 6th century CE (551 CE) event. We suggest that the multiple, distributed channels observed in that reflector’s surface morphology (Fig. 6B) represent a complex back-channeling product produced by the less-organized/more degraded character of the harbor at that time. The Byzantine Era (4th–7th c. CE) was a busy time for Caesarea commercially, but with the exception of a 500 CE renovation, the harbor consisted primarily of the intermediate harbor (Fig. 1D) with very little, if any, surface presence of the outer harbor mole/jetty complex (Figs. 1D, 2; Reinhardt and Raban, 1999). Presuming that the map of reflector “A” gives us the ~post-8th century event state of the coastal sea bottom, the harbor would have been in an even more degraded condition through the Early Islamic (7th–11th c. CE) period, with multiple disorganized approaches rather than a single cohesive entrance (Fig. 6B, right). Recently this chaotic character of the outer harbor at that time was reinforced with the discovery of thousands of gold coins dating to the 10–11th century that were presumably part of a shipwreck discovered on top of the submerged harbor in a depth of only 7.5 m, which could only be possible if that area was not a cohesive harbor at the time. Ship ballast concentrations and refuse have been recognized outside the harbor in a roughly shore-parallel, elongated oval shape that agrees with the pattern of debris that would be expected in an anchoring refuge for commercial transactions, given prevalent wind patterns and typical anchoring scope ratios (Boyce et al., 2009). This overlying refuse may be deposited immediately above the two tsunami horizons in question, suggesting that whatever condition the harbor was in prior to the 749/551 CE events, it was even more heavily compromised afterwards. As a result, by the 6th century CE, commercial ships likely had to anchor offshore as a standard practice.

Recently, in continuing efforts to link terrestrial archaeological stratigraphy to the offshore sequence, evidence has been gathered to suggest that there are two distinct stratigraphic horizons with tsunamigenic features, one dating to the late Byzantine (~6th century CE) and the second to the Early Islamic (8th century CE) periods (Fig. 4). Much of this evidence comprises of shell layers described in the terrestrial excavations that were previously interpreted as dredge debris (see Dey et al., 2014 for detailed discussion). However, thus far, only one offshore layer has been identified (Fig. 4). The original dating of that offshore horizon (Goodman-Tchernov et al., 2009; Fig. 4) was limited to a few sherds of ceramics that were ceramic types that remained in use over a long period that included the late Byzantine period and into the Early Islamic era (~5–8th c. CE), and only one radiocarbon date has been obtained from shell material immediately above the horizon. After a more detailed review of the dating methods used for that horizon in previous studies, recent finds from shallow (< 3 m) water excavations, and review of archaeological reports from the hippodrome coastal area (Dey et al. 2014) we suggest that the single horizon is actually the result of two separate tsunami events that occurred relatively close in time (~200 years), resulting in a single deposit. An upper date of 900–1050 CE (radiocarbon, Goodman-Tchernov et al., 2009) from the horizon immediately above the deposit, gives an upper limit for the tsunamite age, but also supports the possibility that both 6th and 8th century CE tsunami events contributed to the preserved horizon.

Following any tsunami event, sediments eroded and redeposited by the waves are exposed to later erosional and depositional processes. For Caesarea, the normal depositional regime, dominated by sandy sediments from the Nile River to the south, typically provides a positive sediment budget necessary for burying the tsunamite. However, short intervals between tsunami events means that less inter-event sediment is available to bury and preserve the underlying tsunamites. If a buried tsunamite is exposed and eroded during a later tsunami, then that material can be mixed and redeposited together with the later event, resulting in a single horizon.

Evidence for such mixing offshore of Caesarea exists in multiple forms. First, archaeological descriptions demonstrate the presence of tsunamigenic deposits on land south of the harbor, within the adjacent hippodrome area (see Figs. 1 and 2), of both 6th century A.D. and 8th century A.D. deposits (Dey and Goodman, 2010; Dey et al., 2014). In excavations of the shallow intermediate harbor (TN area, Fig. 1C; Reinhardt and Raban, 2008), there is an extensive deposit of mixed (Early Islamic–Byzantine, 4th to 8th century CE) refuse, ranging from high-value intricate items of varying erosion state and exposure—suggesting broad mixing of typical harbor refuse (e.g., broken amphora/pots) and newly introduced, undamaged domestic wares and personal items (e.g., intricate hair combs, fine sections of Islamic coins, statuette, a satchel of copper coins). Unlike other harbor deposits, these materials are of broad origin (domestic, commercial, religious), value range and preservation state, suggesting the kind of non-deliberate and rapid burial a tsunami event would produce. In addition, because the ages of the ceramics found in this excavation range from Early Islamic to late Byzantine (6th through 8th centuries CE), no distinctive stratigraphy offshore today separates what may have been two distinct tsunami events.

The expression of the different horizons in this offshore seismic survey is only possible due to the significant acoustic contrast in the physical properties between the tsunami event layers vs. the background, non-tsunami sediments (Fig. 5). In the case of Caesarea, the background Nile River–derived sands are especially homogenous (siliciclastic, quartz-rich fine sands with a highly conservative mode value of ~169 μm), while the tsunamigenic layers consist of a range of grain sizes and inclusions of varying materials with far wider-ranging physical properties (shell, broken kurkar cobbles, foreign ballast, pottery, etc.). As a result, Caesarea may represent ideal conditions for the application of geophysical methods to tsunamite identification in the coastal zone. Other areas of the Mediterranean, and the world, where coasts with more meandering geomorphological features likely exhibit more variations and micro-environments in their natural background conditions, tsunamite definition is likely to be more problematic. Nonetheless, we feel that our results merit the effort to attempt similar merged mapping and archaeological excavations/sampling elsewhere.

5. Conclusions

The results of the high-resolution seismic survey of Caesarea support previous studies that have argued for the presence of laterally extensive tsunamigenic deposits in and around that ancient harbor complex. Santorini-age tsunami deposits are present, but not everywhere identifiable. The earlier interpretation that the ancient harbor of Caesarea was relatively intact at the time of the first historically documented tsunami that would have impacted it, ~1–2nd century, possibly 115 CE, is supported by the presence of pronounced (backwash) channels in association with the entrance to the ancient harbor. In contrast, the harbor's appearance was much degraded by the time of a known 8th century tsunami (749 CE), which is emphasized by the presence of a series of preserved remnant channels, testifying to multiple backwash paths. These preserved paleo-bathymetric features could be recognized at other archaeological sites and may provide a new preserved indicator for ancient tsunamis, further reinforcing the usefulness of the offshore record, particularly relative to the relatively quickly altered and erased terrestrial record (Szczuciński, 2011).

Caesarea, an ancient urban harbor city with a concrete harbor comparable to many harbors of today, also provides insight into the effects of tsunamis on harbors and the nature of preserved deposits in and around them. We suggest that the intensification and magnification of tsunamis within harbors could provide an additional dataset for targeting and identifying non-documented tsunamis and improving the understanding of their impact on harbor structures, enhancing and expanding on the tsunami catalogues, as well as better understanding broader near and far-field effects elsewhere. A multitude of harbor sites both nearby (e.g., Tyre, Sidon, and Alexandria) and worldwide could contain these useful deposits.

Goodman-Tchernov et al. (2009)

Abstract

A sedimentary deposit on the continental shelf off Caesarea Maritima, Israel, is identified, dated, and attributed to tsunami waves produced during the Late Bronze Age (ca. 1630–1550 B.C.E.) eruption of Santorini, Greece. The sheet-like deposit was found as a layer as much as 40 cm thick in four cores collected from 10 to 20 m water depths. Particle-size distribution, planar bedding, shell taphocoenosis, dating (radiocarbon, optically stimulated luminescence, and pottery), and comparison of the horizon to more recent tsunamigenic layers distinguish it from normal storm and typical marine conditions across a wide (>1 km²) lateral area. The presence of this deposit is evidence that tsunami waves from the Santorini eruption radiated throughout the Eastern Mediterranean Sea, affecting the coastal people living there. Dates for the tsunami deposit bracket both the so-called “high” and “low” chronology for the Santorini eruption. In addition to resolving the question of the extent of tsunami impact from the Santorini eruption, the research presented also provides a new means of discovering, identifying, and studying continuous records of paleotsunami deposits in the upper shelf coastal environment. The latter is key to understanding past events, better interpreting sedimentological records, and creating stronger models for understanding tsunami propagation, coastal management, and hazard preparation worldwide.

Introduction

The Plinian eruption of Santorini (Thera, ca. 1630–1550 B.C.E.; Friedrich et al., 2006; Manning et al., 2006), Greece, in the Late Bronze Age, at an estimated 7.1 on the Volcanic Explosivity Index (McCoy et al., 2000), was one of the largest eruptions in human antiquity (Friedrich et al., 2006; Manning et al., 2006; McCoy and Heiken, 2000; Sigurdsson et al., 2006). The extent to which the eruption precipitated tsunami waves has long been debated, as has the question of the range and magnitude attained by such waves (Yokoyama, 1978).

The position that the Santorini eruption resulted in tsunami waves is based on the reporting of tsunami deposits along coastal areas of Greece and Turkey (Fig. 1A) and comparison of that event with tsunami waves associated with historic eruptions that involved similar eruptive mechanisms (Manning et al., 2006; McCoy and Heiken, 2000; Sigurdsson et al., 2006; Yokoyama, 1978). Computer models incorporating this evidence have shown that near-field and far-field wave amplitudes were significant, with maximum wave amplitudes of 26 m and inland inundation to 200 m along the coast of Crete (Bruins et al., 2008; Dominey-Howes et al., 2006; McCoy and Heiken, 2000; McCoy et al., 2000; Yokoyama, 1978). If the waves propagated from the event were strong enough to reach the coast of Israel, 1000 km away, then presumably other Late Bronze Age coastal sites across the Eastern Mediterranean littoral will likely have been affected as well.

Tsunami literature is full of sedimentary studies of post-tsunami deposits; however, these studies are mainly terrestrial and break off abruptly at the coastline, or at best the low tide mark (Choowong et al., 2008; Hawkes et al., 2007). It has been postulated (Weiss and Bahlburg, 2006), and is shown in this study, that the offshore upper shelf environment can contain preserved tsunami deposits. Traditionally, marine sediments discovered in terrestrial deposits have been used to identify tsunami deposits and assess tsunami magnitude (Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Jankaew et al., 2008; Nanayama et al., 2003). Preserved upper shelf marine tsunami deposits are a new source for field-based tsunami evidence (Reinhardt et al., 2006). The general exclusion of these types of deposits from past literature (with the exception of Krakatau; van den Bergh et al., 2003) is likely due to the difficulty of differentiating tsunamigenic layers from storm signatures and subtle mixing in the nearshore zone.

Method

Four sediment cores were collected (Fig. DR1 in the GSA Data Repository1) and one area (area W) was re-excavated with dredges in the sandy upper shoreface (~15 to 20 m below msl) offshore of Caesarea (Fig. 1B), in order to
  1. determine the lateral extent of a previously identified second century (C.E.) tsunamite (Reinhardt et al., 2006)
  2. test hypotheses related to defining and identifying tsunami deposits using multiproxy methods
  3. differentiate the deposit from possible archaeological anthropogenic sedimentation
  4. determine the appearance of a tsunami deposit sequence seaward of the coastline
The major aims of the analysis were to determine sediment characteristics (i.e., micropaleontology, granulometry) in a known tsunamite as a means of differentiating between normal large storm cycles and tsunamis, and identifying the maximum extent of the tsunamigenic deposit, based on established tsunamite characteristics (Bruins et al., 2008; Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Donato et al., 2008; Morton et al., 2007; Reinhardt et al., 2006).

The study presumed that tsunamite horizons would be areally extensive and thus visible in a majority of the cores, and hypothesized that the deposits would grow gradually thinner seaward. Hence, at greater depths the deposits would be expected to become less visible, with fewer tsunamigenic indicators. The chronology of the cores was determined using ceramic finds, radiocarbon, and optically stimulated luminescence (OSL) dating (Tables DR1 and DR3). Local sea-level change (Sivan et al., 2001) would not have dramatically altered the cores’ positions relative to water depth (Fig. 2).

Tsunamigenic indicators, as defined by previous tsunami studies (Bruins et al., 2008; Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Donato et al., 2008; Morton et al., 2007; Reinhardt et al., 2006) (Figs. 2 and 3), included erosional lower contacts, fining-upward particle-size distribution, imbrication of inclusions, individual or groups of molluscs, mixed wear and poor sorting of molluscs, change or distinctive microfossil assemblage (foraminifera), rip-up clasts, household goods and high-value anthropogenic cultural material misplaced in marine context, rafted organics or pumice, unidirectional tilting of marine installations, and well-rounded beach zone pebbles in deeper contexts. Based on comparisons of particle-size distributions of known events within the cores (Fig. 4), a unique sorting based on particle-size distribution was also recognized as a tsunamigenic indicator at this location. Sediment characteristics of the tsunamigenic and intermediary deposits were described and compared.

Results And Discussion

A minimum of one and a maximum of three tsunamigenic horizons were identified in each of the cores (Figs. 2 and 3; Figs. DR2–DR6). Event 1, ca. 1.5 ka ago, corresponds chronologically with a historically documented event of 551 C.E. (Amiran et al., 1994; Mart and Perecman, 1996; Salamon et al., 2007); it is well represented across all of the cores and trenches, and is also present in the findings of previous archaeological excavations (Raban, 2008; Reinhardt and Raban, 2008, 1999; Reinhardt et al., 2006, 1994, 1998), where this horizon was interpreted solely as isolated deposits of jettisoned archaeological materials, or a storm layer (Boyce et al., 2009; Reinhardt et al., 2006). The new results complement the previous interpretation that onloading and offl oading of goods occurred outside of the harbor (Boyce et al., 2009), particularly in the light of possible tsunami-related damage to the harbor. Tsunamite indicators of event 2, ca. 2 ka ago, which correspond with an historical event of 115 C.E. (Amiran et al., 1994; Kortekaas and Dawson, 2007; Mart and Perecman, 1996), are visible in all of the cores. Event 3, OSL and radiocarbon dated to 3630–3410 cal (calibrated) yr B.P., and thus to the period of the Santorini eruption, was identified in cores 1–4. The Santorini-age event differs from the more recent events in the amount of archaeologically related materials in the deposits (Fig. 3B). During events 1 and 2, Caesarea was already built, and therefore the horizon is rich with related anthropogenic debris from the well-populated port city, whereas no major city is known to have existed at that site during event 3 (Late Bronze Age). Therefore, many of the tsunamigenic indicators present during events 1 and 2 are irrelevant for event 3.

Distinguishing between storm and tsunami deposits has long been a central challenge within tsunami research. Tsunami and storm waves differ in the depth to which they can disturb the sea bottom; as water depth increases, storm influence becomes less apparent, while tsunami influence remains (Weiss and Bahlburg, 2006), and these influences can be visible in particle-size distributions. Contour-map plotting of particle-size distributions visually represents differences in distribution more clearly than with conventional means of data expression (Donato et al., 2008; Beierle et al., 2002), and here provides a very useful tool for differentiating between typical storm events and tsunami events (see Fig. 4 and Figs. DR7 and DR8). For example, particle-size distribution results from the tsunamigenic horizons of core 1 (14.3 m water depth) are characterized by a wider range of grain sizes and poor sorting relative to nontsunamigenic horizons. In addition, large storm horizons are visible between the tsunamigenic events, characterized by a range of particle sizes greater than nontsunamigenic horizons, but more limited than tsunamigenic horizons. In comparison to core 1, the storm deposits particle-size distribution signatures in core 2 (20 m water depth) are nearly nonexistent, while the chronologically correlated tsunamigenic horizons are still visMode Particle Sizeible. Thus, the use of particle-size distribution analysis for interpretation makes it possible to recognize tsunamigenic horizons that would be otherwise untraceable. In addition, multivariable K-cluster analysis of the particle size distributions from core 1 ( 15 m) demonstrated that the tsunamigenic horizons clustered independently, while the storm horizons remained within the range of nontsunamigenic horizons (Figs. DR7 and DR8).

Area W (Figs. 1–3) lacked evidence for the Santorini event due to a pronounced disconformity represented by a missing section of at least 2 ka worth of deposits (Reinhardt et al., 2006). This may be the result of erosion and scouring against the harbor structure during the Roman period tsunami (event 2). In the deeper cores, outside the influence of the harbor structure, traces of the Roman period event remained. In the terrestrial and nearshore zone, no data are available for Santorini-age horizons because this exceeded the depths of the archaeological excavations. There are two claims of Santorini-derived deposits from the Tel Aviv area (Neev et al., 1987; Pfannenstiel, 1960) that have been disregarded as unreliable due to poor dating and weak, single variable evidence (rafted pumice, high terrace shell bed). In light of these new findings, these previous claims may be worth revisiting.

Conclusions

Tsunami horizons coincident with the Santorini eruption were identified from upper shelf submerged sediment cores in the Eastern Mediterranean offshore from Caesarea, Israel, based on the correlation of well-dated horizons with tsunamigenic indicators. The continental shelf contains a wealth of undisturbed deposits to better inform and complete the paleotsunami record worldwide, particularly for the many areas where shelf bathymetry similar to that of the Eastern Mediterranean exists. These findings constitute the most comprehensive evidence to date that the tsunami event precipitated by the eruption of Santorini reached the maximum extent of the Eastern Mediterranean.

Reinhardt et al. (2006)

Abstract

Underwater geoarchaeological excavations on the shallow shelf (~10 m depth) at Caesarea, Israel, have documented a tsunami that struck and damaged the ancient harbor at Caesarea. Talmudic sources record a tsunami that struck on 13 December A.D. 115, impacting Caesarea and Yavne. The tsunami was probably triggered by an earthquake that destroyed Antioch, and was generated somewhere on the Cyprian Arc fault system. The tsunami deposit consisted of an ~0.5-m-thick bed of reverse-graded shells, coarse sand, pebbles, and pottery deposited over a large area outside of the harbor. The lower portion of the deposit was composed of angular shell fragments, and the upper portion of whole convex-up Glycymeris spp. shells. The sequence records tsunami downcutting (~1 m) into shelf sands, with the return flow sorting and depositing angular shell fragments followed by oriented whole shells. Radiocarbon dating of articulated Glycymeris shells, and optically stimulated luminescence (OSL) dates, constrain the age of the deposit to between the first century B.C. and the second century A.D., and point to the tsunami of A.D. 115 as the most likely candidate for the event, and the probable cause of the harbor destruction.

Introduction

On 13 December A.D. 115, a tsunami struck the ancient port city of Caesarea (Israel) and was recorded in the Talmud (Shalem, 1956; Amiran et al., 1994). According to the description, the wave impacted the Levantine coast with effects recorded at Caesarea and Yavne (Fig. 1). The tsunami was likely caused by a powerful earthquake that destroyed the city of Antioch (Fig 1; Ambraseys and Jackson, 1998) and originated somewhere along the eastern Cyprean Arc (Ben-Avraham et al., 1995).

The construction of Caesarea's harbor by Herod the Great in 21 B.C. is well documented by excavation work and descriptions of the harbor by the historian Josephus Flavius (Whiston, 1999; Holum et al., 1988). The reasons for the rapid decline in the harbor, about one century later, are less clear, and heavily debated (Reinhardt and Raban, 1999; Hohlfelder, 2000). However, the favored interpretation has been the catastrophic destruction of the harbor by an earthquake; although the role of a tsunami has been considered, no conclusive evidence has ever been found (Raban, 1992, 1999; Reinhardt and Raban, 1999; Mart and Perecman, 1996)
.

Records of sub-recent (past 2000 yr) tsunamis in the eastern Mediterranean are based primarily on textual records with variable accuracy (e.g., Neev et al., 1973; Amiran et al., 1994; Mart and Perecman, 1996; Ambraseys and Jackson, 1998; Karcz, 2004), none of which has been substantiated with geological or archaeological evidence. Here we present clear evidence for an ancient tsunami recorded in shallow shelf deposits at Caesarea, and infer the impact on the harbor structure. While we do not have the resolution in radiocarbon, optically stimulated luminescence (OSL), or ceramic dating to precisely confine the event to a given year, or decade, the A.D. 115 tsunami is an excellent candidate for creating the deposit. The evidence from Caesarea shows that thick and extensive tsunami deposits can be preserved in shallow clastic shelf environments.

Tsunami Evidence

Clear evidence of a paleo-tsunami is most often detected where marine allochthonous sediments are found in an otherwise terrestrial freshwater or brackish system in coastal lakes, estuaries, lagoons, etc. (e.g., Goff et al., 2001; Dawson et al., 1990; Carey et al., 2001; Minoura and Nakaya, 1991; Atwater, 1992; van den Bergh et al., 2003). The occurrence and characteristics of tsunami deposits on the shallow shelf receive little attention, as it is often perceived that the deposits have low preservation potential or would be impossible to differentiate from tempestites produced by large-scale storms or other shelf erosional processes. However, recent outcrop studies have identified evidence for preservation of tsunamites in Cambrian and Holocene shelf sequences, showing that they can be preserved in shallow shelf environments. The interpretation of these examples is hampered, however, by the lack of recent sedimentary analogs for comparison (Pratt, 2002; Fujiwara et al., 2000).

The lack of baseline information is, in part, due to limitations of sediment coring and to problems in retrieving representative coarse-grained sediment stratigraphy in clastic shelf settings. Underwater geoarchaeological excavations provide several advantages for recovering and studying these types of deposits. They can penetrate most sediments, they expose large areas for stratigraphic analysis, and, in archaeological sites, large quantities of material culture can be recovered for dating (Reinhardt, 1999). We used this approach at Caesarea to document a thickly stratified shell deposit whose taphonomic characters and dating (14C, OSL, material culture) indicate that it was formed by the 13 December A.D. 115 tsunami. Without the geoarchaeological excavations, this deposit would not have been recognized, as sediment coring would not have provided a broad exposure to identify and map the taphonomic and sedimentary characteristics of the tsunami deposit.

Results

We excavated trenches to depths of up to 2.2 m at several sites outside the harbor as part of an earlier study at Caesarea (Boyce et al., 2004). At three sites (W4, W6, and W7) the trenches revealed a sequence of shelf sands containing an upper horizon of Byzantine-era ship's ballast and pottery (0.5 m thick, Unit B) and an underlying distinctive shell layer at 1–1.5 m depth. The thickness of the shell horizon varied (0.2–1 m) but could be correlated across excavation areas as a continuous horizon. The shell deposits were predominantly Glycymeris (mostly violescens), which inhabits the infralittoral zone, typically below 18 m water depth (Barash and Danin, 1992). Two sediment samples from each shell subhorizon in Area W7 (~1000 cm³, 700–800 g) were sorted by shell content, and fractional weight abundance (%) was calculated for whole unrounded Glycymeris shells, angular Glycymeris fragments, rounded whole Glycymeris shells, and other shell fragments. The whole Glycymeris shells (unrounded) were further sorted into size fractions.

The shell taphocoenosis was clearly different between the modern storm active unit (A and top of B) and the tsunami shell beds (D1 and D2). The ballast deposit (Unit B) contained abundant whole Glycymeris shells (55%) with a large percentage of rounded shells (28%), and the size distribution of the whole shells was skewed with a predominance of shells in the 6–10 mm range. The taphonomic characters of the shell in the upper ballast layer were commensurate with the accumulation of shell amongst the ballast stone from multiple storm events. This is typical storm deposition, and has been seen elsewhere in the harbor excavations (e.g., Reinhardt, 1999). There was no distinct orientation to the shells and they were predominantly whole, rounded, disarticulated Glycymeris shells.

In contrast, the deeper shell horizon was characterized by two subunits (D1 and D2), which were separated by a sharp uneven contact. The upper horizon (D1) consisted of 73% convex-up oriented disarticulated Glycymeris shells, a smaller quantity (12%) of rounded shells, angular fragments (11%), and other shell material (4%), and the size distribution of the whole Glycymeris shells displayed low peakedness with a relatively even distribution through the size range. Horizon D2 was different in taphonomic character from Unit B and D1, as it consisted of 86% angular fragments, 10% whole shell, 4% other shell, and no rounded fragments. The distribution of whole shell was also different, as it was skewed toward smaller valves with more than 80% of the valves being less than 10 mm in diameter. These taphonomic characters are distinctly different than those of the shells in the ballast deposit (Unit B).

There is taphonomic evidence of fragmentation in the lower portion of the shell horizon (Unit D2), which can only be indicative of a tsunami. The high percentage of fragmented shells (and abundant stress fractures), along with their angular breaks, is atypical of storm shell accumulations on the shelf. The Glycymeris shells are very robust with no preexisting weakness, and tend to degrade through abrasion rather than any significant breakage, as seen in the shells in the upper ballast deposit. The abundance of fragmented Glycymeris shells in the lower part of the shell unit, and their lack of rounding, indicates a high-energy event horizon with no subsequent reworking since deposition. The fragmentation is consistent with intense wave turbulence, shell-to-shell impacts, and shells striking the harbor moles or bedrock under high wave energy, as generated by a tsunami.

The accumulation of whole Glycymeris shells (D1) on top of the shell fragments (D2) likely indicates differential settling of shells after the tsunami. The smaller angular fragments would settle out of the water column first, followed by the larger valves, which would sink in a helical path and at a slower rate (Brett, 2003). The convex-up orientation is due to deposition under a unidirectional current, and likely from the return flow of the tsunami wave. This is a characteristic orientation for bivalve shells in riverbeds and in tidal currents (Brett, 2003; Allen, 1984). In the modern environment, densely packed convex- up Glycymeris orientations were observed in shallow (1–2 m), narrow (2–3 m) rills in the sandstone bedrock to the east of the excavation sites, where strong storm surge waves orient the shells. The shells from the upper tsunami unit were oriented convex upwards but were not stacked vertically and did not form any "nests," indicating rapid continuous deposition without sustained oscillatory currents reorienting the shells (Brett, 2003; Allen, 1984). The thickness of the shell horizon is atypical of the normal shelf stratigraphy, as storm accumulations are normally composed of thinner shell layers because the storms cannot sort and concentrate enough shell material to form an accumulation up to 50 cm in thickness.

Additional evidence for the tsunami origin for the shell deposit comes from the distribution of 14C and OSL dates, and pottery ages, which showed intense scour of the seabed. Articulated Glycymeris shells were found in the sand (E) below the shell unit, in the shell horizon (D1 and D2), and in the overlying sand (C) up to the ballast deposition, which were 14C dated from W7. OSL dates of the sands from the same units from W6 resulted in similar ages. The 14C dates from the lower sand unit (E) of 3130–2841 B.C., and from the overlying fragmented shell unit of 81 B.C. to A.D. 125, were corroborated with OSL dates of 2375–3133 B.C. and 238 B.C. to A.D. 216, and with small pottery fragments characteristic of the first and early second centuries A.D. (‘Eastern Sigillata B’ and Early Roman bag-shaped jars of ‘Riley 1A type’; Raban, 2004), indicating a significant erosional scour that is also seen in the truncation of faint sedimentary and bioturbation structures in Unit E. The overlying sand (Unit C) has OSL and 14C dates similar to the tsunami deposit. Such evidence is commensurate with scour from a tsunami wave, deposition of shells, followed by infill of sand from the receding tsunami and/or through storm deposition after the event. The rapid infilling of the erosional scour is indicated by the articulated Glycymeris shells within Unit C, which indicate little reworking. Considering the error on the 14C and OSL dates, it could have taken anywhere from years to decades for the shelf to re-equilibrate and infill the tsunami scour. Abundant ceramic material from the fourth to sixth centuries A.D. was present in Unit B, indicating the upper limit of the active storm layer within the stratigraphy.

The pottery in the shell horizon indicates that the tsunami occurred after the construction of Caesarea in the late first century B.C., and after Josephus described the harbor in grand terms between A.D. 75 and 79. Josephus referred to seismic events throughout the region, and had the harbor withstood a tsunami, he would have mentioned it, as a glorification of the harbor's strength and engineering prowess (Josephus Flavius; Antiquities of the Jews XV.9.6, in Whiston, 1999). The radiometric dates further constrain the event to no later than A.D. 200, making the A.D. 115 tsunami the likely candidate for the shell deposit. No complete or accurate record of all tsunami events exists; however, the other known events for the Levantine coast are either too old (20–26 B.C. flooding at Pelusium) or too young (A.D. 306 destruction at Sidon and Tyre; Mart and Perecman, 1996)
.

Impact on the Harbor

In a previous study (Reinhardt and Raban, 1999) we presented evidence indicating seismic damage in the first to second centuries A.D. that severely compromised the Caesarea harbor structure. We presented evidence that seismic activity was the cause of the destruction of the harbor; although, considering the new data, some of the evidence could equally be interpreted as a result of a tsunami.

The harbor mole was constructed of large (390 m³) concrete blocks (caissons) laid on the seafloor (e.g., Raban et al., 1999). The impact of the tsunami bore would have shifted the mole's foundation and undermined its shoreward edge, causing the offset of the caissons as observed in the modern harbor ruins (Raban et al., 1999; Reinhardt and Raban, 1999). The impact of the tsunami may have also loaded the underlying sediments to the point of liquefaction, leading to further foundering of the caissons. It is envisioned that during the impact of the tsunami bore, significant quantities of shoreface sediments and shell materials would have impacted onto the mole and bedrock surfaces, generating a large volume of broken shell material. The articulated Glycymeris shells in the tsunami deposit indicate transport from the deeper shelf, as the shallowest habitation depth for these bivalves is 18 m. In the harbor itself, the tsunami and resulting seiche would have been highly destructive, causing further erosion and undercutting of the harbor mole. High-energy conditions represented in the first- to second-century A.D. sediments from the inner harbor may be from this event (Reinhardt and Raban, 1999). In the subsequent return flow phase, further erosion of the shelf may have occurred, and the graded shell bed (Unit D) records the sorting and deposition of the shell materials with the waning tsunami. The inclusion of pottery fragments in D2 indicates transport of sediment from the shallower harbor area, indicating deposition by return flow of the tsunami. In a final phase, the tsunamite was buried and the remaining scour depression was infilled by sand deposited by longshore currents and storm activity on the shelf
.

While earthquake damage cannot be ruled out as a contributing factor to the demise of Caesarea's harbor, our new data point to the tsunami of 115 A.D. as a contributing cause of its early destruction. Further work is required to better constrain the extent of the tsunami deposit at Caesarea and to correlate it with other potential shelf sediment records at Yavne and other coastal sites impacted by the tsunami. Historical sources record a large number of destructive tsunami events in the eastern Mediterranean; we anticipate that investigation of shelf sediment records on these coasts will yield important geological information about these events, and insights into their destructive effects (e.g., Sidon and Tyre; Marriner et al., 2006).

Reinhardt and Raban (1999)

Abstract

Geoarchaeological analysis of ancient harbor deposits has answered questions regarding the timing and extent of the destruction of the harbor at Caesarea Maritima built by Herod the Great on Israel's Mediterranean coast. By using stratigraphic, micropaleontological (foraminifera), and geochemical (Sr isotopes) analyses of the ancient harbor deposits we can establish a late first to early second century A.D. date for the destruction of the harbor. This destruction occurred earlier, was more rapid and widespread than previously proposed, and was probably caused by seismic activity. The new excavations also indicate that during the fourth to early sixth centuries A.D., geomorphological processes and siltation within the inner harbor allowed this area to be used in a limited capacity as a harbor.

Introduction

Two thousand years ago the ancient harbor at Caesarea Maritima, on the Mediterranean coast of Israel, was a key center for maritime shipping; it is now an important submerged archaeological site. In 21 B.C., King Herod the Great, ruler of Judea, built an all-weather harbor at Caesarea (Fig. 1): the harbor structure was a unique engineering feat for its time (Holum et al., 1988). The harbor breakwaters were built out from the coastline to the open sea, using a combination of hydraulic concrete and sandstone ashlars (Brandon, 1996; Fig. 1). The construction of the harbor breakwaters rapidly transformed the smooth Israeli coastline in the area from a high-energy littoral environment to a quiet-water lagoon. The harbor was completed in 10 B.C. and was described by Josephus Flavius (a Jewish historian) in A.D. 72-75 (Holum et al., 1988).

On the basis of archaeological evidence, the remains of the Herodian harbor are believed to be submerged 6 m below the water surface. However, this interpretation is controversial because the evidence regarding the timing of the destruction of the harbor and the proposed neotectonic mechanism causing the submergence have been questioned (Hohlfelder, 1988, 1993, 1996, 1998; Mart and Perecman, 1996; Mazor, 1974; Neev et al., 1987; Nir and Eldar, 1987; Raban, 1992, 1996; Raban et al., 1989; Reinhardt et al., 1994; Ronen, 1989; Fig. 1). Most of the theories regarding the destruction of Herod's harbor have relied on the interpretation of architectural remains, numismatic evidence, literary records, and material cultural artifacts recovered from the ancient harbor. However, these data have been largely inconclusive and the various theories have been debated (Hohlfelder, 1993; Kadman, 1957; Levine, 1975; Oleson et al., 1994; Oleson, 1996; Raban, 1992; Ringel, 1988).

Here we present new geoarchaeological evidence from the harbor sediments that conclusively determines the destruction of the harbor in the late first to early second century A.D., and documents a limited rejuvenation of the harbor in the fourth to early sixth centuries A.D.

Methods

Previous excavations conducted in 1994, both on land and underwater in areas 19, 114, and TN1 within the inner harbor, were conducted in order to determine the evolution of the harbor (Reinhardt et al., 1998a; Yule and Barham, 1999; Raban, 1996; Raban et al., 1999b; Figs. 1 and 2). However, these three sections were stratigraphically incomplete because they were missing key deposits in their basal levels. We later found these deposits in six sections excavated in 1996-1997 (SW1, SW2, SW3, TN1b, TN1c, TN2).

The excavation of these sections was conducted using scuba and an underwater dredge (Raban et al., 1989). In areas where the sediment was consolidated, stratigraphic relationships were mapped and sampled from the balk wall. In areas where sediment was noncohesive a metal caisson was used (Hohlfelder, 1993). The strata were dated by the identification of the large corpus of pottery and coins from the deposits, and from 14C dates of wood fragments.

Micropaleontological analyses were performed using the methods found in Reinhardt et al. (1998a) and were used to determine the three biofacies (marine, brackish-marine, and brackish; Table 1) in conjunction with the 87Sr/86Sr data. The relative proportions of porcelaneous and hyaline foraminiferal taxa and their diversity can be closely linked with salinity; higher diversity porcelaneous dominated assemblages are typically found in normal marine and hypersaline conditions (Murray, 1991).

Correspondingly high proportions of hyaline taxa dominated by Ammonia tepida can also be indicators of lower salinities; however, Ammonia tepida is also a notably euryhaline species (Murray, 1991; Almogi-Labin et al., 1995) and is not always a good indicator of brackish-water conditions. However, by combining the foraminiferal and Sr isotopic results, we were able to determine three biofacies related to salinity (Reinhardt et al., 1998b). We obtained salinities from 87Sr/86Sr values measured from bivalves, gastropods, foraminifera, and ostracodes using the methods found in Reinhardt et al. (1998a, 1998b). We used the Sr isotopic and concentration values for ground waters in the Israeli coastal plain and for eastern Mediterranean seawater for our two end members for generating our mixing curve (Reinhardt et al., 1998a; see Table 1).

Stratigraphic Data

Introduction

From our data, four temporally constrained stratal units (loci Ll—L4) representing changing environmental conditions within the harbor were recognized and are described from oldest to youngest as follows.

IA—Destruction Phase

The first to second century A.D. basal rubble unit (L4) was found on the carbonate cemented sandstone bedrock (locally known as kurkar) and was characteristic of a high-energy water deposit (Fig. 2). The rubble was framework supported with little surrounding matrix and composed mainly of cobble-sized material, which was well rounded, heavily encrusted (e.g., bryozoans, calcareous algae), and bored (Lithophaga lithophaga, Cliona) on its upper surface. The rubble had variable lithologies including basalts, gabbros, and dolomites, all of which are absent on the Israeli coastal plain and were likely transported to the site as ship ballast (probably from Cyprus). The surrounding matrix was composed of shell material (mainly Glycymeris insubricus), pebbles, and coarse sand. The pottery sherds found in this unit were well rounded, encrusted, and dated to the first to second century A.D. The date for this unit and its sedimentological characters clearly records the existence of high-energy conditions within the inner harbor about 100–200 yr after the harbor was built. This evidence of high-energy water conditions indicates that the outer harbor breakwaters must have been severely degraded by this time to allow waves to penetrate the inner confines of the harbor (Fig. 3, A and B).

Indication of the rapid destruction of the outer harbor breakwaters toward the end of the first century A.D. is derived from additional data recovered from the outer harbor. In the 1993 season, a late first century A.D. shipwreck was found on the southern submerged breakwater. The merchant ship was carrying lead ingots that were narrowly dated to A.D. 83–96 based on the inscription "IMP.DOMIT.CAESARIS.AUG.GER." which refers to the Roman Emperor Domitianus (Raban, 1999). The wreck was positioned on the harbor breakwater, indicating that this portion of the structure must have been submerged to allow a ship to run up and founder on top (Raban, 1999; Fig. 3B). Because Josephus praised the harbor in grand terms and referred to it as a functioning entity around A.D. 75–79, and yet portions of the breakwater were submerged by A.D. 83–96, we conclude that there was a rapid deterioration and submergence of the harbor, probably through seismic activity
.

Seismic activity affected settlements on the Levantine coast (including Caesarea) in the past and is recorded in historical documents (Amiran et al., 1994). Evidence for neotectonic subsidence of the harbor has been reinforced by separate geologic studies (stratigraphic analysis of boreholes, Neev et al., 1987; seismic surveys, Mart and Perecman, 1996) that recognize faults in the shallow continental shelf and in the proximity of Caesarea; one fault extends across the central portion of the harbor. However, obtaining precise dates for movement along the faults is difficult. Archaeological evidence of submergence can be useful for dating and determining the magnitude of these events; however, at Caesarea the evidence is not always clear. The submergence of a paved floor in area F, which is ~5 m below sea level, is probably due to faulting, although the function and original elevation of the structure are not clear (Fig. 1; Raban et al., 1989).

The submergence of the outer harbor breakwaters at the end of the first century A.D. could have also been due to seismic liquefaction of the sediment. Excavations have shown that the harbor breakwaters were constructed on well-sorted sand that could have undergone liquefaction with seismic activity. In many instances the caissons are tilted (15°–20° from horizontal; Raban et al., 1999a) and at different elevations, which could be due to differential settling (area K; Fig. 1). However, the tilting could also be due to undercutting by current scour from large-scale storms (or tsunamis) and not exclusively seismic activity.

Our data from the inner harbor cannot definitively ascribe the destruction of the harbor at the end of the first century A.D. to a seismic event, although some of the data support this conclusion. However, regardless of the exact mechanism, our sedimentological evidence from the inner harbor and the remains of the late first century A.D. shipwreck indicate that the submergence of the outer breakwater occurred early in the life of the harbor and was more rapid and extensive than previously thought
.

L3—Infilling Phase

The deposits of the second to fourth centuries A.D. (L3) are represented by a well-sorted sand unit indicating continued high-energy deposition within the harbor basin (Figs. 2 and 3B). Boulders found in the sands were heavily encrusted with Ostrea edulis, suggesting that the boulders were exposed for a significant period of time in a high-energy water regime. Subsidence and destruction of the outer harbor breakwaters would have allowed the incursion of sand and its accretion in the inner harbor. The fining-upward sequence in the sand unit indicates a gradual reduction in the water energy through to the fourth century A.D. This gradual reduction in water energy was probably due to the deposition of a sand bar across the intermediate portion of the breakwater, possibly associated with the deteriorated harbor structure (Figs. 2 and 3C). Our placement of the barrier in Figure 3C represents its furthest possible extent west, because only well-sorted sand and no mud unit was found in excavations in area Q (Fig. 1). In addition, no visible anthropogenic structure, such as a seawall, was found in this portion of the harbor. It is interesting that the sudden development of a highly restricted lagoonal environment represented by the overlying muds occurred suddenly because separate bivalves (Tellina planata) and their burrows were found intact and in situ in the upper portion of the sand unit (Fig. 2).

L2—Harbor in Use

Organic-rich muds (L2) from the section record highly restricted conditions within the harbor during the fourth to early sixth centuries A.D. (Figs. 2 and 3C). The mud unit was found in all areas of the inner harbor and is dated from the third to early sixth century A.D. (Yule and Barham, 1999; Raban, 1996; Raban et al., 1999b). The mud units contained abundant shell, botanical (i.e., olive pits, date pits) and material cultural artifacts, and many wooden timbers, including some from ship hulls (14C dates from fourth to early sixth centuries A.D.). The foraminifera, molluscs, and Sr isotopes found within this unit are indicative of normal marine to brackish waters (Fig. 2; Reinhardt et al., 1998a, 1998b; Yule and Barham, 1999). Sr isotopes analyses from sections located in the eastern portion of the inner harbor (areas 19, 114, and TN1a) revealed that the muds were deposited in brackish-water conditions. These brackish waters were created by the large influx of ground water and to a lesser extent municipal waste waters into the inner harbor (Reinhardt et al., 1998a, 1998b; Yule and Barham, 1999). The more marine conditions found in the sections from SW, TN2, and TN1c represent a salinity gradient moving seaward from the inner harbor, or salinity stratification of the water column within the inner harbor. The kurkar bedrock in areas SW and TN2 is deeper at 4.6 m below sea level than the eastern sections of the inner harbor, and this area must have been affected by the intrusion of marine waters, probably through an opening in the lagoon. The restricted lagoon conditions would have created an ideal environment for harbor activity during the Byzantine period (fourth to sixth centuries A.D.) and a channel into the inner harbor at that time may have been dredged. The water depth in the lagoon was ~2–3 m and thus could have been used by smaller craft to offload goods from the larger ships in the outer harbor (Raban, 1996). This method of moving goods from ship to shore was the standard mode of offloading cargo after the third century A.D., because there were no large-scale harbors in operation in the Mediterranean after this period in antiquity (Blackman, 1982).

A limited renovation of the outer harbor also occurred sometime early in the sixth century A.D. Procopius of Gaza, an early Christian orator, claimed that the harbor was in a poor state; he observed shipwrecks regularly in the exposed harbor (Holum et al., 1988). According to Procopius, the Byzantine Emperor Anastasius I (A.D. 491–518) provided resources to refurbish the harbor (Holum et al., 1988). This report has been substantiated by the discovery of a large number of shipwrecks from the fourth to fifth centuries A.D. on the harbor breakwaters and the evidence of renovations, indicated by a rubble spill on the northern breakwater.

The removal of the sand bar and deterioration of lagoonal conditions occurred sometime in the sixth to seventh centuries A.D. The sand bar was removed, possibly through reactivation of the fault extending across the middle of the harbor and a rise in relative sea level of ~0.5 m during this period recorded on the inner harbor quay walls (Raban, 1996). The faulting and rise in relative sea level would have displaced the surf zone landward and caused the sand bar to migrate toward the east and accrete against the eastern wall of the inner harbor (L1). The continued accretion of sand in the inner harbor eventually allowed the area to be used as a building site for Islamic (Abbasid) structures in the middle eighth century A.D. (Raban, 1996). The remnants of this sand-bar migration are seen in SW (1, 2, 3) and TN2 as a thin sand unit on top of the mud (base of L1), which thickens in TN1a and into the inner harbor as indicated in areas 19 and 114 (L1; Figs. 2 and 3D).

L1—Destruction

The final stratigraphic unit was composed of rubble, which represents several phases of harbor activity during the seventh to thirteenth centuries A.D. (L1; Figs. 2 and 3D). The rubble in the inner harbor was of highly mixed origins, a large proportion of building stone and marble columns, along with abundant intact pottery, glass, metal fragments, wood, and animal bone. Both pottery and rubble were variably encrusted and bored, and the rubble included variable amounts of matrix, indicating that the unit was deposited rapidly. From its composition we believe it was probably artificially dumped terrestrial material. The accumulation probably occurred during the seventh century; Muslim forces captured the city (A.D. 640) and deliberately filled the harbor to prevent seaborne invasions by the well-equipped Byzantine navy (Raban, 1996). Cultural material concentrated on top of the rubble and a seawall built on top of the rubble (Crusader wall and quay) indicate that some maritime activity continued within the inner harbor until its abandonment in A.D. 1265.

Conclusions

The harbor sediments provided the best source of information regarding the structural integrity of the harbor and the interactions between humans and the natural environment. This combined geological–archaeological study indicates that the early and widespread destruction of the harbor was at the end of the first century A.D., and a rejuvenation of maritime activity within the inner harbor occurred in the fourth to early sixth centuries A.D.

Our results indicate that harbor restoration may have not been entirely of human origin; natural processes created an ideal environment for a shallow harbor during the Byzantine era. These results also correspond to results from land excavations, where evidence of intense economic activity was found in the Byzantine period (Holum et al., 1988).

Fritsch and Ben-Dor (1961)

At the very deepest spot where the airlift penetrated, beneath huge stone blocks which teetered precariously above the divers' heads, was uncovered a large wooden beam. Beneath its protective cover the divers found the only whole amphora of our dig. This proved to be a second century Roman vessel. The fact that it was found under the tumbled beam and masonry would indicate that these things were catapulted into the sea at the same time. Since there is a strong earthquake recorded in the area of Caesarea in the year A.D. 130 [JW: this refers to the Eusebius Mystery Quake - could also be the Incense Road Quake], it may possibly be that the harbor installations of Herod were destroyed at that time.

Other finds recovered from the original bottom, now under fifteen feet of sand, included numerous sherds of second century amphorae, corroded bronze coins, ivory hairpins, colorful bits of glass and other objects of the Roman period
. Two objects were of special significance. One was a small lead baling seal with a standing winged figure. It has a pinpoint hole near its center, and a rather deep, depressed line on the back of it, as though made by a wire.3

The other object was probably the most important thing discovered at Caesarea this past summer. It was a small commemorative coin or medal made of an unidentified alloy, about the size of a ten-cent piece, with two holes drilled through it as if it might have been worn as a pendant. Upon the face of it there is the representation of the entrance to a port flanked by round stone towers surmounted by statues. Arches border the jetty on either side of the towers, and two sailing vessels are about to enter the harbor. Two letters, KA, may well be the abbreviation for the word Caesarea. The other side of the coin shows the figure of a male with a long beard and a tail like a dolphin, with a mace-like object in his hand. Coin experts who have seen this piece agree that it is unique, and that it undoubtedly depicts the ancient port of Caesarea. It may have been issued to commemorate some important occasion at Caesarea in the first or second century A.D.
Footnotes

3. This object may be an amulet, the winged figure representing Horus, the Egyptian sun god who wards off lurking evils. Cf. E.A.W. Budge, Amulets and Superstitions (London, 1930) 166. A close examination of the original piece, however, leads one to conclude that it is a baling seal.

Potential Tsunami associated with Eusebius' Martyr Quake (303-306 CE)

Neither Reinhardt et. al. (2006) nor Goodman-Tchernov et. al. (2009) nor Goodman-Tchernov and Austin (2015) saw evidence of a tsunami in near shore shelf deposits of Caesarea around 304 CE. Salamon et. al. (2011) noted that a tsunami was reported in a number of earlier earthquake catalogs (e.g. Shalem, 1956, Ben-Menahem, 1991, Amiran et al., 1994) which several of the cataloguers (Shalem, 1956 and Amiran et al., 1994) viewed as doubtful - according to Salamon et al (2011). The alleged tsunami was likely generated from Eusebius' report of the sea casting up the body of the martyrdom of Apphian at the gates of Caesarea at the same time as the [Eusebius Martyr Quake] in Sidon. Salamon et al (2011) noted that a seismic sea wave is not specifically mentioned in Eusebius' text and it is common along the eastern Mediterranean coast, even in normal weather conditions, that the sea casts up dead bodies of drowned people at the shore.

Coin Hoard Quake - 4th century CE

Discussion

Discussion

References
Notes by JW

Raphael and Bijovsky (2014) examined "a large hoard of 3,700 copper coins" found in the excavations of what may have been a synagogue. They describe the discovery of the coin hoard as follows:

In 1962, during the excavations at Caesarea, Avi-Yonah unearthed a large hoard containing 3,700 copper-alloy coins, in a building that he identified as a synagogue. The latest coins in the hoard date to 361 CE, suggesting that the synagogue was destroyed by the 363 CE earthquake.

... The finds from the excavation were only partially published. Much of the information, such as locus numbers, is not always clear and the exact location of the hoard is not marked on a plan or described by Avi-Yonah. Nevertheless, his written descriptions clearly state that the hoard was found in the building and the strata are fairly well defined. A photograph shows Avi-Yonah in the building during the excavation kneeling next to the in situ hoard (Fig. 1).
The coins were found in Stratum IV. The original excavator (Avi-Yonah) "gave no reason for the destruction of Stratum IV." In discussing evidence for seismic destruction in Caesarea, Raphael and Bijovsky (2014) provide the following:
None of the excavations revealed large scale damage in Stratum IV: "there is no evidence of wholesale destruction across the site, especially since the wall lines are still mostly intact based upon photographic record. Yet not much remains of the structure either in stratum IV or stratum V" (Govaars et al. 2009:132). After the earthquake debris was cleared, the synagogue was rebuilt. Stones from the previous synagogue were reused for the building of the stratum V synagogue, but the hoard was not found until Avi-Yonah's excavations. Govaars wrote "the direct relationship of the coin hoard to a structure is uncertain and, therefore the coin evidence cannot be used to date the still unknown structure" (Govaars et al. 2009:42). This is a somewhat peculiar statement considering the coins were found in the synagogue and are on the whole well preserved, homogeneous and well dated. Avi-Yonah was convinced that the hoard was directly related to the Stratum IV building: "The fact that a hoard of 3,700 bronze coins was found in the ruins of the synagogue itself that were buried in 355/356 AD indicates that this synagogue was built in the end of the third or the early fourth century, and was destroyed in the mid fourth century AD" (Avi-Yonah 1964:26 n. 5).

... Evidence at Caesarea

The subject of earthquakes and tsunamis has been partially reviewed by several archaeologists who directed or participated in the excavations at Caesarea. None of the monumental buildings across the site revealed earthquake damage that dates to the fourth century CE.

The report of remains from the excavations of the Promontory Palace at Caesarea, dated between the early fourth century and early sixth centuries, does not mention destruction levels (Levine and Netzer 1986:176-184). In other excavations, the Roman and Byzantine-period warehouses and granaries (horreum) gradually fell into ruin over a considerable period. Neither the main streets, pavements, sewage and water systems, the theater, amphitheater nor the stadiums of the Late Roman and Byzantine periods show signs of destruction that suggested earthquake damage (Humphrey 1974:32; Porath 1996:114-120; Porath 2003 and Porath [pers. comm.]).

If the town was partially damaged or destroyed in the 363 CE earthquake, as the Harvard Syriac letter [i.e. the letter attributed to Cyril] describes, then other than the large coin hoard, the earthquake left no clear, tangible evidence. The damage was cleared and buildings were repaired or rebuilt. Although none of the archaeological reports mentions earthquake damage, several reports clearly describe the abandonment and/or the rebuilding of public buildings in the second half of the fourth century CE. None of the authors provided a reason for their destruction or abandonment.

Tectonic evidence such as collapsed columns, thick piles of debris or warped walls are elusive throughout the fourth century architecture of Caesarea. Why is this typical earthquake damage missing? Are the written sources and the numismatic evidence sufficient proof of the 363 CE earthquake in Caesarea? It is important to note that among the various violent, politically motivated upheavals that took place in the second half of the fourth century, one of the main candidates explaining destruction at archaeological sites is the Gallus Revolt (352 CE). However, none of the sources that describe this revolt mention Caesarea Maritima (Geller-Nathanson 1986:34)
1,453 coins from the hoard of coins were identifiable by mints and dates. They ranged in age from 315 CE to the first quarter of the 5th century CE. 11 of these coins ranged in age from 364 - 421 CE and post dated 363 CE. The bulk of the hoard, however, were struck between 341 and 361 CE. The authors noted that 11 of the post 363 CE coins may have been intrusive. The authors opined that the many coins from Julian II shows that the coins could not have been concealed before 355 CE ruling out the Gallus Revolt (352 CE) as a cause for the loss of the hoard.

Raphael and Bijovsky (2014) noted a similarity to a 8550 coin hoard from Qaṣrin which also contained a "small number" of coins minted after 361 CE which were interpreted by Betylon as intrusive coins lost by people returning to the site after the 363 CE earthquake however, on further examination, Betlyon and Killebrew (2016) published that there had been a change in opinion and concluded that the Qaṣrin coin hoard was deposited after 367 CE.

Vault 2 in Area CV Quake - mid-7th century CE

Discussion

Discussion

References
Notes by JW

According to Raban et al. (1993 v. I:64), Vault 2 in Area CV collapsed suddenly, crushing pottery vessels that had been resting on the floors. The destruction was dated to the mid-7th century CE, with researchers attributing the collapse to seismic activity. This dating was based on ceramics and coins, the most recent of which belonged to the reign of Heraclius [r. 610-641 CE].

Two possible earthquake events were suggested as causes: the ~634 CE Sword in the Sky Quake and the 659/660 CE Jordan Valley Quake(s). Raban et al. (1993 v. I:64) reported that Vault 2 was a two-story structure that collapsed downward, with its arcade falling downward and westward. Additionally, evidence suggested that the second-story floor had flipped over during the event.

Raban et al. (1993 v. I)

Area CV (Vault Project)

Main Discussion

From 1971 through its final field season in 1987, the Joint Expedition to Caesarea Maritima (JECM) concentrated much of its research effort on its Field C, a Roman and Byzantine-Period insula (city block) located south of the Crusader City and adjacent to the Mediterranean Sea. One area of intense study in this insula was its western extremity, where a series of storage vaults (horrea) were uncovered that in turn served as the substructure for a U-shaped public building above.29 Of these vaults, Vault 1 was the best preserved, and it was excavated during the 1973 and 1974 field seasons (Blakely 1987).

Excavation revealed that, while this Herodian structure originally served as a storehouse, by the end of the 1st century C.E. it had been converted, at least partially, into a Mithraeum (Bull 1978). This cultic function appears to have continued for a few centuries, until, at the end of the 3rd century or the beginning of the 4th, the structure was reconverted into a storehouse. The vault appears to have served as a storehouse again from that time until its abandonment, probably in the late 7th or early 8th century.

In the final publication of the ceramics collected during the excavation of Vault 1, (Blakely 1987, 1988), a wide variety of amphoras were identified. It was determined that these amphoras had originated all around the Mediterranean basin. These results suggested that neighboring vaults in this complex might contain valuable stratified evidence relating to the periodic growth and decline of Roman and Byzantine trade.

Planning for a new research endeavor that was to be a part of CCE began in 1989, when K. Holum and A. Raban invited Archaeological Assessments, Inc., to organize a project within the framework of CCE. The scientific aims of this project were to be compatible with those of CCE but were outside of the specific research goals then outlined by CCE. During 1989 and 1990 a research design for the excavation of another Herodian vault was prepared. The design emphasized both refined stratigraphic excavation and the recovery and analysis of ceramic data, with the overall goal of studying patterns of trade over time. In 1991 a small test probe was excavated in the northwest corner of Vault 2 (Horton et al. forthcoming). The results of this probe,30 suggested that good stratified materials were preserved in Vault 2, and that this would be a suitable location for conducting the Caesarea Maritima Vault Project (CMVP).

Vault 2 is located immediately to the south of Vault 1, and is far less intact than its neighbor (Bull et al. 1986: fig. 13). Indeed, only the eastern end of Vault 2 is still standing, and the rest of it appears to have collapsed in antiquity and to have been covered with windblown sand. Although what now seems to be a small Fatimid installation was placed into this sand deposit over the western parts of Vault 2, apparently this installation did not remove the stratified Roman and Byzantine layers in the vault below the collapsed vaulting. The intact eastern end of Vault 2 is covered by part of the U-shaped building excavated by JECM (Spiro 1992: 260 fig.21). There can be little doubt that the sturdy construction standards used in this structure account for the preservation of the vault below. Thus the present situation is that the eastern end of Vault 2 is covered by a structure already mostly excavated, for which JECM’s squares and balks are clearly evident, while west of this building the material slopes down over the collapsed vaults to the sea.

... From the evidence that was found upon pavement 1047 and on the clay and plaster layers of CV/2, it is clear that Vault 2 and this structure immediately in front of it remained in use up to the point of collapse. The structure appears to have been destroyed suddenly, because collapsed vault and other structural elements crushed pottery vessels that were resting on the floors (figs. 132, 133). No fire was associated with this destruction.

Vault 2 appears to have collapsed downward, while the frontal arcade structure appears to have fallen both to the west and downward. From the collapsed superstructure of the arcade one can determine that the second storey had a white tesselated floor, probably with a black border, since many fragments of this floor were found in the destruction, including one segment over 3 m. long and at least a meter wide where it emerged from the balk. This segment was upside down, having apparently turned over during the collapse. Above this floor segment many broken roof tiles were found. Thus it appears that the structure was of two storeys and roofed.

This destruction dates to the mid-7th century. The latest coins in the destruction date to the reign of Heracleus [r. 610-641 CE]
. Examples of the pottery found in this destruction are included in figure 134. Figure 134:1 is a Peacock and Williams Class 44 amphora (1986: 185-87). This amphora type has been previously recorded at Caesarea by Riley as his Type 5 amphora (1975: 31, 33). Subsequently, Adan-Bayewitz followed Riley’s amphora typology (1986: 102, Ill. 103, figs. 2:4-5), but the type was not recognized by Peleg and Reich (1992: 154, fig. 15:15). The best study of the vessel remains that of Peacock and Williams. The Class 44 amphora is known all around the Mediterranean basin, being commonly found in Egypt (Adams 1962, Quibell 1912, Emery and Kirwan 1938), Libya (Riley 1981a), Carthage (Hayes 1976: 117, Class 8, fig. 21:15; Riley 1981b; Fulford and Peacock 1984: 20-22, 119-20, figs. 34:1-2), Athens (Robinson 1959), the Aegean (Hayes 1968,1976), Cyprus (Catling and Dikigoropoulos 1970, Catling 1972), Italy (Frova 1977), Spain (Keay 1984), the Black Sea (Bamea et al. 1971, Yakobson 1951), and on the Yassi Ada wreck (Bass and van Doominck 1982). The vessel is even known in Britain (Thomas 1981).

The most comprehensive discussions of this vessel type in Palestine were by Riley (1975: 31, 33) and by Landgraf (1980: 82-83, fig. 26:2). Although rare, the type was present at Mount Nebo (Sailer 1941: pl. 149:32), at both Bethany and Bethpage (Sailer 1957: 210, pl. 114:1-2), Cistem II at Beth-She’an (FitzGerald 1931: 38, pl. 31:27), Room 32 ofthe Jerusalem Street Level in the Tyropoeon Valley (Crowfoot and FitzGerald 1929: 81, pl. 14B: 29; Magness 1989), Area A at Ashdod (Dothan and Freedman 1967: 34, fig. 14:2) and at Pella in 6th and early 7th century contexts (Smith 1989: 105-106, pls. 43a, 48:7, 52:8).

The petrological study of this vessel by Koucky at Pella, done independently from Peacock and Williams, suggests the same source regions. Peacock and Williams, following the earlier work of Williams (1979), ascribe the manufacture of this vessel to the northeastern part of the Mediterranean basin, but are unable to suggest its principal content. The vessel appears in contexts spanning the 5th through mid-7th centuries.

Figure 134:2 is a typical Gaza or Ashkelon amphora, a well-known type that is again common in the 5th through 7th centuries (e.g., Peacock and Williams 1986: 196-99). Figure 134:3 is an example of Palestinian Fine Byzantine Ware. No parallels have been reported for this exact vessel, but the general type is well known. The closest published parallel to this vessel type is the Fine Byzantine Ware Type Beta Ware B bowl with outsplayed rim (Gichon 1974: 123 and fig. 2). At Bethany "from Cave 41 in the grove," Sailer, (1957: 269, figs. 50:3343 and 52:3208, pl. 122a) describes eleven vessels that appear to fit this class, although here in a gray ware. Sailer noted that these vessels were similar to some of the bowl wares found in the 6th to 8th century street deposit in the Tyropoeon Valley (Sailer 1957: 269; Crowfoot and FitzGerald 1929: 79, 81-82). Our closest parallel is from the north wall ofJerusalem, where Hamilton described, "the most characteristic and persistent type," in the 6th and early 7th centuries as a ware matching our bowl. Hamilton’s fig. 8:5 is an apparent match in ware and size (1944: 12-14, fig. 8:5).

Wightman described a similar bowl at the Damascus Gate, Jerusalem (1989: 15, pl. 18:12), noting its "finely levigated and hardfired orange ware, and . .. fine band-polishing inside and out." Wightman dated these pieces between the third quarter of the 7th century and the first quarter ofthe 8th. Other examples appear to be found in Byzantine contexts at Siyar el-Ghanem (Corbo 1955: fig. 20:17, 20, 22) and Herodium (Birger 1981: 76, fig. 13:5), and in a probable 7th century context in the religious complex at Ramat Rahel (Aharoni 1964: 14-17, fig. 7:12). Birger dates the vessel form as early as the 4th century, noting a similarity with African Red Slip forms 51 and 52 (Hayes 1972). Since all known findspots of this vessel are in Palestine, and usually in likely 7th century contexts (also 6th and even 8th), the 4th century analogy is probably erroneous. Magness (1989) suggests dates after the mid-6th Century and through the 7th for this type.

Figure 134:4 is a typical late Palestinian red sandy amphora, dating to the late 6th century through possibly the 8th (Peacock and Williams 1986:191-92, 216). Figure 134:5 is a type identified by Adan-Bayewitz as Cooking Ware Type 3 at Caesarea (AdanBayewitz 1986: 108). This is not a common cooking vessel at Caesarea, but it is known elsewhere at the site in a mid-7th century context (Adan-Bayewitz 1986). Adan-Bayewitz could point to no parallels in Palestine, but did note parallels at Kellia (Egloff 1977:103 Types 138-40) and Cyprus. The Cypriot parallels come from probable 7th century contexts, Mersineri near Dhiorios, which is a kiln site (Catling 1972: 13 and 63-64, figs. 7: P96 and 27: P185), and in both the Kornos Cave deposit and the bench deposit at Salamis (Catling and Dikigoropoulos 1970: 48-49 and fig. 3, #14, pl. 29B; 56, #12-13, fig. 7 #7-8). The vessel is also found at Carthage, where Fulford and Peacock suggest that it might be imported. They date the form from 550 through the 7th century, but prefer the dates 600-625 (1984: 16 ware 2.3,185-87 type 24, fig. 69). The vessel class was also found by the Michigan team at Carthage in Deposit 24, dated to the second half of the 7th century on numismatic evidence (Hayes 1978: 52 and fig. 13:31), and in Deposit 25, dated 10th-12th centuries but with mixed earlier materials (Hayes 1978: 56 and fig. 14:41). These vessels are listed as Late Ware VI, a 7th Century type. In the latter deposit Hayes (1978: 58) also identified a similar Cypriot import (?), fig. 15:50. It was also found on the Yassi Ada wreck (Bass and van Doorninck 1982).

Given the numismatic and ceramic evidence, a date in the mid-7th Century seems likely for the destruction in CV/2. The latest Byzantine occupation thus began in the second half of the 6th Century, probably around 575 C.E. It had two later phases, the construction of cemented partition wall 1058 and the later construction of the very crude stone wall 1067/2033, and was destroyed in the mid-7th century. When destruction occurred, the structure apparently was still in use. Destruction appears to have been sudden and violent, with the buildings collapsing but without accompanying conflagration. This scenario appears to fit earthquake destruction far better than conquest and would be in accord with Holum’s theory about the impact of the Islamic conquest on Caesarea (Holum 1992).

Russell (1985: 39) noted two earthquakes in Palestine in this general period, 633 and June 659. Based on the data collected and on the assumption that the destruction was caused by an earthquake, neither date should be preferred over the other. A personal preference for June 659 is based on attributing the crude wall in front of the vaults, 1067/2033, to an Islamic occupation, since the wall is definitely not of the same character as the other Byzantine walls. This entire suggestion is only a hypothesis which remains to be tested
.

After destruction the entire area of excavation was covered by wind-blown beach or dune sand (fig. 132). It was not until the Fatimid period that a large pit was excavated into these layers, down to the Byzantine collapse of Vault 2. Only the edges of this pit are visible in CV/1 (fig. 132) and CV/2, but the remains suggest some sort of industrial installation. The pit fill contains Fatimid period ceramics, both glazed and unglazed, ceramic production debris (fig. 135), scrap bone from inlay production, and slag. The excavation of this pit is planned as a major focus of next year’s excavation. Wall 1044 is the sole other late wall. It was north of our excavated area, having been discovered by JECM in the mid-1970s. This wall probably relates to Islamic re-use of Vault 1.

A small probe was excavated through pavers 1047 near the center of the exposed portion of the pavement (fig. 130). Removal of the pavers and part of robbed-out Wall 1048/1049/1050 revealed parts of an earlier stone structure which must pre-date the 3rd century, a plaster lined pit, L 1054, and a late 3rd or early 4th century ashlar wall located under 1048/1049/1050 and at a slightly different orientation. The latter wall, 1057, runs over pit 1054, which was filled in when it was constructed. This wall appears to have extended the common wall between Vaults 1 and 2 toward the west. A selection of the amphoras found in pit 1054 and dating to the construction of this wall (fig. 136), is typical of those found in 2nd through early 4th Century contexts. The only coin found in this pit fill was resting on the plaster floor and dates to the early 2nd Century.

Area CV/10 (fig. 130) was opened in 1991 to explore the architectural relationships of stucco decoration found attached to the western exterior wall of the transverse vaults at the southwest comer of JECM’s Field C (cf. Horton et al. forthcoming). This stucco came to light during sand clearance by a bulldozer, and the trench was laid out to cover the sector immediately west and to the south of the vault wall (CV/10003) and plaster. Any remains post-dating the Byzantine period, in all likelihood only dune sand, had already been removed before excavation. By the end of 1992, this trench had reached Late Roman levels (135-324 C.E.), but it has not yet succeeded in dating Wall 10003 or the stucco.

As noted, Wall 10003 appears to be the western exterior wall of a series of Herodian period transverse vaults. The foundation level of this structure has yet to be reached. At the lowest exposed point, plaster surface 10040 extends westward from the vault wall. This surface also abuts Walls 10002 and 10039, two walls in existence when the plaster surface was laid Little can be said about the two latter walls except that 10002 seems to be earlier, while 10039 was built against it. Wall 10002 may be the remains of an arch set against vault wall 10003, and plaster 10040 may represent the bottom of a basin. Based on ceramic evidence, all of these structures must pre-date the mid 3rd century To the west three superimposed soil layers 10028/1034/1035, discovered in a probe, can also be dated to the 2nd and 3rd centuries, based on ceramics.

A wide variety of evidence of Late Roman/Early Byzantine Period structure and soils was found with CV/10. The most prominent feature is a large kurkar, plaster, and cement structure which appears to be the remains of a basin or a sump, L 10012/10025 (fig. 137). At a slightly higher level to the east, additional elements of this structure came to light, L 10031, 10033, and 10036. A late 3rd or 4th century date seems best for this entire unit. Tumbled kurkar ashlars in mixed fill and ash covered these structural elements, as well as the remains ofthe previous plaster floor 10040. Based on ceramic evidence, this ashlar fill, 10024/10037, again has a likely 4th century date.

A mid-Byzantine phase is seen in the trench in three major units. The first was Wall 10013, a north-south ashlar wall of kurkar which ran across the trench (fig. 137). This wall alligned perfectly with Wall 1045 (fig. 130), and with a fragmentary wall stub in trench CV/2 but outside of the excavated portion. If this is part of the same building plan, and the masonry does appear similar, then a series of store fronts or an arcade extended north-south along the entire insula against the western front of the vault complex. Trench CV/10 provides the best dating evidence for the construction of this wall, probably in the 4th or 5th century C.E. Also associated with this phase were pavers 10011, located immediately west of this wall. Fills associated with this phase include L 10017, 10019, and 10027. All of these layers directly covered the structures and debris of the previous phase.

The latest preserved Byzantine phase includes much new structure. A second wall, 10005, was constructed parallel to wall 10013, between it and vault wall 10003. This new wall of kurkar ashlars was exposed in 1991 and partially removed this year. Between Walls 10013 and 10005 were Walls 10022 and an earlier eastern extension of 10013. Both were covered by a soil layer, L 10020, while fill layer 10017 covered the southern part of the trench. Stone-lined drain channel 10016 ran north-south across the trench. It was put out of use by ceramic and lead drain pipe 10015 (fig. 138). This drain pipe may have been part of the same drain as 1068/2041, datable to the mid-6th Century. A portion of flagstone pavers 10011 was found in the western portion of the trench, probably dating to the 6th Century. All extant remains had been leveled to about 5.15 m. above MSL. In the east these remains had been covered by bull-dozed fill 10014 and in the west by modern parking lot 10009.

A basic stratigraphic/chronological understanding of the mid-Roman through Byzantine remains in this area has now been obtained. In order to understand the function and extent of these remains, further excavation connecting CV/1 and CV/10 will be needed between the vault front and the sea. Such an enlargement of excavation area would also allow the Early Roman and Herodian layers to be examined.
Footnotes

28. With some editing by K. Holum.

29. On these excavations in general see Bull et al. 1986: 31-38, and Bull et al. 1990: 7. A plan of the U-shaped building has appeared in Spiro, 1992: 260, fig. 21.

30. As interpreted by Blakely and H. Katherine Sheeler.

Summary

Excavation in Area CV during 1992 should be viewed primarily as preparatory work. A limited amount of evidence relating to pre-Byzantine Caesarea was recovered. These remains should raise the expectation of significant finds (e.g., roads, shops, or a sea wall) between the vaults and the modern coast. The data recovered from Byzantine contexts, especially Late Byzantine, suggest that an arcade or row of store fronts was constructed along the western face of the vaults. If Walls 1045 and 10013 are indeed the same wall, then a large-scale planned construction of an arcade or store fronts in the mid-Byzantine period appears likely. These appear to have continued in existence until the collapse of this part of the site, probably in the mid-7th century. By the 7th century the CV/1 and 2 vault-front structure was a roofed two-story building with a tesselated floor on the second story. Collapse of this structure appears to have been sudden in the mid-7th century, possibly relating to one of two earthquakes, 633 or 659. A second unifying feature of the vault front area is a late 6th century drain pipe which appear to run almost the length of the block, from where JECM excavated it in the mid 1970s southward through Trench CV/10.

At the end of this Byzantine occupation, this part of the site appears to have been abandoned and to have been covered by clean dune sand from the beach. Excluding later burials, the only significant Islamic occupation of JECM’s Field C appears to have been the probable Fatimid industrial installation which has been isolated, but remains unexcavated, over Vault 2.

Geologic Probe

Just to the west of Trench CV/10, a geologic probe was excavated through the modern parking lot down to MSL. The trench was actually two intersecting 3 x 5 m. bulldozer cuts positioned at right angles. The goal in these probes was to establish the limits of stratified structural remains and to locate a Roman or Byzantine sea wall, if one was present.

The parking lot had been built by the Israel National Parks Authority over the past fifteen years. The fill from this construction activity was clear and lay between 2.0 and 3.0 m. thick, ending on beach sand at a level of about 2.5 m. above MSL. Modem yoghurt containers attested the date of the parking lot construction, which was also well remembered by those who excavated JECM’s Field C in the 1970s.

Below the beach sand a series of stratified layers came to light before the water table was reached at about 0.72 m. above MSL. The water here was fresh. The layers down to this level contained no clear structural elements, although some of the layers could have been built. Pottery from these levels ranged from Byzantine at the top to nothing but early Roman at the bottom. Included in one of these lower layers was a piece of 5th century B.C.E. Attic fineware. The lowest levels above absolute sea level appeared to be structural fills containing little cultural material, although some fragmentary pottery was evident.

The conclusion reached through the excavation of these probes is that no structural elements associated with land structures were present this far to the west. What could not be determined was whether structures had ever been located this far west, and whether and such structures had been destroyed in antiquity by wave action or human agency. The question whether there was a true Roman/Byzantine period sea wall and its location therefore remains open. Other than what appeared to be soil layers deposited by Roman-Period builders at the very bottom of this probe, no structure was found.

mid-8th century CE Earthquake

Discussion

Discussion

References
Temple Platform and Octagonal Church

Plans

Plans

Normal Size

  • Caesarea with principal sites mentioned by Dey et al(2014)

Magnified

  • Caesarea with principal sites mentioned by Dey et al(2014)

Discussion

Dey et al (2014) report that evidence for seismic destruction due to one of the mid 8th century earthquakes is present adjacent to the Temple Platform and possibly at the octagonal church.
At Caesarea, the best evidence of destruction attributable to the 749 earthquake comes from Area TPS, on the S side of the Temple Platform, where a thick layer of debris marks the end of the Umayyad occupation of the Late Byzantine bath complex, which was subsequently mulled and built over in the later 8th century - see Raban and Yankelevitz (2008:81) and Arnon (2008:85). Another probable effect of the earthquake was the collapse of the octagonal church on the platform - see Holum et al (2008:30-31).

Terraced Gardens

Plans

Plans

Normal Size

  • Caesarea with principal sites mentioned by Dey et al(2014)

Magnified

  • Caesarea with principal sites mentioned by Dey et al(2014)

Discussion

In addition, there appears to be evidence of landward tsunami deposits. After the Muslim conquest in the 7th century, Caesarea depopulated. In the late 7th or early 8th century CE, the coastal strip south of where the Crusaders would later build their fortifications was transformed into lush terraced gardens irrigated by wells and cisterns ( Dey et al, 2014). Marine layers found on top of these gardens included Glycymeris, a non-edible deeper water bivalve. Atop the marine layer was, in some areas, a burial ground with a funerary inscription providing a terminus ante quem of 870 CE. A terminus post quem of c. 500 came from a reflecting pool fronting the Temple platform and overlain by the marine layer. Dey et al (2014) suggest that the most likely explanation for the transformation from gardens to burial ground was an intervening episode of tsunamogenic destruction. They discussed the potential landward tsunamogenic deposit as follows:
The most substantial strata attributable to a marine inundation of mid-8th-c. date appeared in the SW sector, along the coastal strip south of the Crusader fortifications. Extensive tracts of these deposits between the temple platform and the theater, a shore-parallel distance of nearly 800 m, were uncovered (and removed, usually mechanically) in the 1970s and early 1980s under the auspices of the Joint Expedition (JECM). The bulk of the deposits lay in a shallow depression situated c.10 m above mean sea-level (MSL) and separated from the sea by a low ridge 15 m above MSL. From the landward side of the ridge, beginning c.50 m from the shore, these marine layers stretched inland as far as 300 m from the sea. 14 They comprised two distinct, superimposed sequences, each consisting of a thick, lower layer of densely-bedded (and in some cases imbricated) shells, rubble and sherds up to 1.5 m thick, topped by a dark, silty layer 20-40 cm thick. Datable materials in the second, upper sequence placed its formation around the 14th c. 15 In the lower sequence, dated by the excavators approximately to the 8th c. on the basis of finds, numerous disarticulated human remains turned up, as well as at least one complete skeleton in Area C, interbedded with the surrounding strata of shells and silt. 16 Like the rest of the materials, this corpse was probably deposited by a (cataclysmic) natural event. As D. Neev and K. Emery indicated in their report, there were no signs of a man-made grave, and the surrounding horizontal strata were uninterrupted above and below the skeleton; such 'culturally non-appropriate burials' are now recognized as a typical feature of tsunami deposits.17 The most likely scenario would have corpses deposited by the retreating waters of the tsunami and immediately covered with more detritus, keeping the articulated skeleton undisturbed by scavenging animals or human intervention.

Area LL

Figures

Figures

Normal Size

  • Fig. 1D Aerial view of site LL and southern part of the Upper aqueduct from Everhardt et. al. (2023)
  • Fig. 1E Aerial view of site LL showing locations of cores, baulk, and collapsed corridor from Everhardt et. al. (2023)
  • Fig. 3 Early phases Plan of Area LL from Ad et al (2018)
  • Fig. 8 Wall Collapse in Stratum VI (Umayyad) from Ad et al (2018)
  • Fig. 3 Sections of Cores C1 and C2 and the Southern Baulk from Everhardt et. al. (2023)
  • Fig. 2B Destruction layer(s) showing building stones suspended in anomalous sands from Everhardt et. al. (2023)
  • Fig. 2C Archaeological fill directly underlying anomalous deposit along with inset of fire-burnt stones from Everhardt et. al. (2023)
  • Fig. 4 Lab Analysis of Core C1 from Everhardt et. al. (2023)
  • Fig. 5 Lab Analysis of Southern Baulk from Everhardt et. al. (2023)
  • Fig. 8 Projected direction of tsunami surge from Everhardt et. al. (2023)

Magnified

  • Fig. 1D Aerial view of site LL and southern part of the Upper aqueduct from Everhardt et. al. (2023)
  • Fig. 1E Aerial view of site LL showing locations of cores, baulk, and collapsed corridor from Everhardt et. al. (2023)
  • Fig. 3 Early phases Plan of Area LL from Ad et al (2018)
  • Fig. 8 Wall Collapse in Stratum VI (Umayyad) from Ad et al (2018)
  • Fig. 3 Sections of Cores C1 and C2 and the Southern Baulk from Everhardt et. al. (2023)

Discussion

Site LL is located just north of Caesarea's inner harbour. Ad et al (2018) excavated the site which was in use from the Herodian period to the Umayyad period. A storage structure (aka "the warehouse") was identified in the western part of the site which appears to have been constructed in Herodian times and remained in use, as it underwent changes, until the middle of the Umayyad period (~700 CE). After the Islamic conquest of Caesarea (640 CE), rooms were partitioned, floors were raised, construction was added and some of the openings were sealed. Ceramics indicate that the site was abandoned at the end of the 7th century CE after which it suffered two major destruction events before re-occupation occurred in the mid 8th century CE in what was interpreted as Abbasid Strata V (the Abbasid Caliphate began ruling in 750 CE). During the renewed Abbasid occupation, destruction debris were preserved as the builders preferred to level the area and build above the destruction layer(s). The destruction events within Stratum VI (Umayyad) appear to be an earthquake and a tsunami; both likely a result of the the Holy Desert Quake of the Sabbatical Year Quake sequence.

Ad et al (2018) report that during the earthquake event several ceilings collapsed inward, and there was evidence of a fire in the eastern warehouse.1 In the collapse in the corridor, the original order of the courses of the wall or vault could be clearly identified (Fig. 8) adding confidence to a seismic interpretation. During the subsequent tsunami event, a layer of sand and collapsed building stones had accumulated to a height of more than 2 m in Rooms 8–11 in the western warehouse and to a height of 1.5 m in Rooms 12–14 and the corridor of the eastern warehouse. Everhardt et. al. (2023) further examined the destruction deposits by taking cores and radiocarbon samples as well as examining burn evidence and a baulk inside the collapsed corridor.

The cores (C1 and C2) were taken in the collapsed corridor after the Abbasid floor was removed, thus sampling the destruction deposits. See Fig. 1E for location of the cores (and southern baulk) and Fig. 3 for photos and descriptions of the cores and the southern baulk. A ~20 mg. charcoal sample from the top 3 cm of sediment in the Umayyad archaeological fill and one untreated sample of various organic material (~20 mg) from the top 5 cm of the same layer in core C1, as close as possible to the contact with the lower anomalous deposit, were collected for radiocarbon dating. Everhardt et. al. (2023:14-15) report that radiocarbon dates of charcoal and organic material from the upper contact of the Umayyad archaeological deposit (Unit C) range from 605 to 779 CE2 which is in agreement with the phasing of Ad et al (2018) and compatible with destruction layers that were deposited in 749 CE.

Cores C1 and C2 were sampled and analyzed for grain size distribution, foraminiferal assemblage, total organic carbon (TOC), and Inorganic Carbon (IC). An additional 13 surface surface samples, including from storm surge deposits, were also collected, analyzed, and compared with the analysis of the Cores and Southern Baulk in order to help distinguish if a tsunami deposit was indicated in the cores and baulk. Portable-Optically Stimulated Luminescence (P-OSL) dating was also performed on the cores. Four sedimentary units (A-D) were identified in the two cores are were described as follows :
Unit Alias Description Interpretation
A ‘anomalous’ deposit clean, loose quartz sand with no sedimentary structures or cultural artifacts. tsunami deposit
B same sediment as Unit A but with additions of several marine-encrusted potsherds and reddened, partially heat-fused sand clusters. earthquake and fire debris mixed with a tsunami deposit
C 'Umayyad archaeological fill' a dark gray/brown (10YR 6/2), organic-rich layer with many cultural artifacts, including potsherds, glass shards, shells, beach pebbles, charcoal, and bone fragments. Post abandonment deposition from the latter half of the Umayyad period - typical of an ancient garbage dump
D compact earthen floor Umayyad or earlier floor
Everhardt et. al. (2023) interpreted ‘anomalous’ deposit Unit A as tsunamogenic primarily based on grain size distribution and an abundance of foraminifera along with other indicators. As for Unit B, they noted that the reddened, partially heat-fused sand clusters were in agreement with the presence of reddened in-situ building blocks along the intact eastern wall of the room (and elsewhere along the walls) which indicated that a fire took place before the tsunami struck. They also noted an abundance of charcoal found in the upper Umayyad archaeological fill. They viewed the presence of marine-encrusted potsherds as an indicator that these inclusions were previously submerged in the marine system long enough for the encrustation to take place, suggesting that they were transported from the sea to land at the time of the event which in turn could indicate that the tsunami water and deposits extinguished the fire.

Everhardt et. al. (2023) proposed that the lower southern baulk was also a tsunamogenic deposit related to 'anomalous" deposit Unit A in the cores.
Footnotes

1 Everhardt et. al. (2023:5) reports that fire-reddened walls (see inset of Figure 2C) were found at the same level as the destruction layer(s).

2 Everhardt et. al. (2023:14-15) described the radiocarbon samples as follows:

A single piece of charcoal from the surface of the Umayyad archaeological fill (Unit C) in core C1 has been radiocarbon dated with 95.4% probability to 649–687 cal CE (73.5%) or 743–773 cal CE (22.0%), consistent with the archaeological finds. A second radiocarbon age was measured on a mix of small organic materials from the same layer as the previous charcoal sample, with a result of 605–665 cal CE (95.4% probability).

Other locations

Everhardt et. al. (2023), while citing citing Holum et. al. (2008) reported that isolated reports describe single-column-fall damage or other structural failures in Caesarea due to the Holy Desert Quake of the Sabbatical Year sequence.

Goodman-Tchernov and Austin (2015)

Abstract

Modern observations have shown that harbors are especially vulnerable to the effects of tsunamis, both due to their position on the coastline and the tendency for tsunamigenic eddy production within enclosed harbor basins. Presumably, this was as much the case in the past as in the present. The Roman-era mega-harbor Caesarea Maritima, which is today submerged in some parts up to 5 m below sea level, is an ideal research site for understanding these impacts. Over the past three decades, archeologists, geologists and historians have searched for the cause of the rapid demise of this harbor, turning to explanations ranging from offshore faults, seismic disturbances, general failure and deterioration, to liquefaction and settling on unconsolidated sands. While tsunamis are recorded repeatedly in the Eastern Mediterranean historical record, it has only been in the past decade that physical evidence directly attributed to tsunamigenic sediments along the Israeli coastline near Caesarea has been documented. To date, deposits from at least three tsunami events that impacted the harbor have been identified in sediment cores, coastal exposures and archeological trenches, but no laterally continuous picture has been produced. In this study, using a dense offshore survey produced by a high-resolution subbottom profiler, shallowly buried sediment horizons offshore of Caesarea produce distinctive reflectors that correlate with the tsunamigenic stratigraphic sequence identified in cores and excavations. These surface structure maps allow for a laterally extensive reconstruction of these distinctive deposits. The results have led to the following conclusions and interpretations:
  1. multiple offshore tsunamigenic horizons at Caesarea can be recognized
  2. individual tsunamigenic event horizons result in distinctive and unique surface morphologies that elucidate tsunami-based channeling/backflow processes
  3. these backwash channels can be used to assess the general physical condition of the harbor at the time of each tsunami occurrence, ultimately revealing major differences between the state of the harbor following earlier events (i.e., 2nd c. CE) vs. later events (6–8th c. CE)
We conclude that the combined acoustic-sampling approach is an effective way to document the interaction of tsunamis with harbor complexes and adjacent coastlines over millennia.

I. Introduction and background

1.1. Evidence for tsunami impacts on coastal morphology and associated structures

Coastal morphology, including adjacent landforms, artificial structures, and coastal-fringing natural features (i.e., extensive coral reefs, mangroves, e.g., Baird et al., 2005; Fernando et al., 2005; Kunkel et al., 2006; Giri et al., 2008) can all influence the impact of tsunami wave flow (Hon et al., 2007; Sugawara et al., 2012). As the inundating wave breaches the coastline, natural and man-made obstacles that obstruct or impede the wave’s force can lead to channeling and variable flow, both as the wave advances inland and retreats seawards. Such energy redistribution is also evident in affected rivers or artificial channels, in which tsunami flow will continue inland to distances far exceeding that of uninterrupted portions of the coastline (e.g., Crete 1956, Bruins et al., 2008; Okal et al., 2009; northern Japan 2011, Mori et al., 2011; Goto, 2011a; Chile 2010, Fritz et al., 2011). The tsunami return/outflow is even more influenced by the presence of structures, and therefore is typically characterized by channeling (Umitsu et al., 2007; Feldens et al., 2009), which can result in shore-perpendicular bathymetric and topographic features (Atwater et al., 2010). In Sumatra following the 2004 tsunami, evidence of such complex back-flow included filled channels, boulders moved into deeper water, movement of sand into previously silty areas, and man-made rubble immediately seaward of the shoreline (Feldens et al., 2009; Goto, 2011b). Similarly, in northern Japan following the Tohoku-Oki earthquake in 2011, canals and road features often corresponded with variations in tsunami inundation heights along the Sendai Plain.

Amongst the range of coastal structures that interact with tsunamis, harbors have been identified as locations of acute magnification and flow intensification in both simulations and field studies (Raichlen, 1966; Synolakis and Okal, 2005; Lynett et al., 2012). For example, during the 2004 tsunami, at the Port of Salalah, Oman, strong currents produced inside the harbor caused a 285 m ship to break away from its moorings and beach on a nearby sandbar after spinning and drifting for hours (Okal et al., 2006). At Port Blair, India, harbor structure damage included movement or complete collapse of the jetties (Kaushik and Jain, 2007). Examples are also available for the far-field effects of tsunamis, where harbors have been damaged while adjacent coastlines experience little inundation. One such harbor is located in Crescent City, CA; this site was damaged repeatedly following both near-field events, such as Alaska 1964, as well as far-field tsunamis, such as those generated from seismic events in 2006 (Kuril Islands) and in 2011 (Tohoku-Oki) (Griffin, 1984; Horrillo et al., 2008; Kowalik et al., 2008; Wilson et al., 2013). Widespread documentation of ships originally moored in harbors that have been displaced inland and/or damaged along the adjacent coastline during tsunamis are common; this phenomenon includes relatively small events, such as the tsunami following the 1999 Izmit earthquake in Turkey, with varying reports of wave heights, but with possible localized heights of ~6 m (Rothaus et al., 2004).

Following a tsunami, a variety of characteristic markers can be left behind, both on the shallow sea bottom and on shore, including massive debris fields, sheets of sand, muddy film, and/or eroded surfaces, amongst a list of over thirty-two published indicators (e.g., Goff et al., 2012). Depending on the specific surface conditions of the impacted coastline, e.g., surficial sediment types, strandline morphology and available unconsolidated debris, coastal zone bathymetry can be altered as contents carried within the tsunami flow drop out as the wave energy dissipates (Jaffe et al., 2012). Inland, tsunami-based deposits are generally characterized by landward thinning (Morton et al., 2007), unless interrupted by some limiting structure or topography.

The patterns of tsunami deposits and bathymetric forms created by these waves can be informative regarding the character of the affected coastline and adjacent offshore areas (Richmond et al., 2012). In northern Japan, for example, artificial channels and a highway constructed on the Sendai Plain before the 2011 Tohoku-Oki earthquake influenced the distribution of tsunami-deposited sediments and wave run-up heights (Sugawara et al., 2012), relative to the distribution of known preexisting tsunami deposits. Recognizing and mapping tsunami-related features from historical events should inform us as to the state of both natural and artificial structures on a coastline which were affected by these tsunamis, including the influences of the back-wash phase of sedimentation. In this study, the ancient harbor of Caesarea Maritima, on the eastern Mediterranean coast of Israel (Fig. 1), is presented as an ideal site to consider this tsunami-impact phenomenon, and how and whether the physical evidence for such recurring impacts might be preserved over two millennia.

1.2. Caesarea Maritima: the ancient harbor, its deterioration and demise, and recent tsunami research

When King Herod had the city of Caesarea built on the coastline of what is now Israel between 25 BCE and 9/10 BCE, he applied Roman city planning, organization and building techniques, including the costly installation of a state-of-the-art, artificial mega-harbor (Holum et al., 1988; Hohlfelder, 1988, 1996; Raban, 2009; Votruba, 2007; Raban, 2008; Fig. 1). The natural environment afforded little protection or anchorage, with the exception of periodic, remnant, exposed ridges of eolianite sandstone (locally referred to as ‘kurkar’) roughly paralleling the coastline immediately offshore. These bedrock structures are exposed and eroded lithified dunes 135,000–45,000 years old (Sivan and Porat, 2004). The harbor was constructed on portions of this bedrock and extended seaward onto unconsolidated Nile River–derived sands (Goldsmith and Golik, 1980; Neev et al., 1987; Stanley, 1989; Zviely et al., 2007), with the use of man-made foundations. Roman engineers succeeded in this task by building wooden frameworks (‘caissons’) on land, then towing them into position where they were submerged, filling them with hydraulic cement, and ultimately finishing them with above-water superstructures. Fields of large cobbles (less than 20 cm diameter) were emplaced beneath the caissons (Raban, 2008), presumably to give them added stability against erosion and undermining, suggesting that the engineers of the time were aware of the inherent risks for constructing directly on unconsolidated sandy sediments. These caissons were arranged in rows to produce the spinal walls of the harbor, completing the entire project in less than 15 years (Brandon, 1996). This efficient approach to harbor construction continues to be used today. For example, ‘Mulberry I’ and “Mulberry II”, created by the allies during WWII in preparation for the D-Day landings, were also artificial islands constructed in a similar manner for the purpose of providing supplies and reinforcements until an established harbor could be secured (Stanford, 1951; Ryan, 1959; Bettwy, 2015).

Descriptions made ~70 CE by historian Flavius Josephus describe a fully functional imperial mega-harbor, exceeding the size of most contemporaneous Mediterranean harbors (Raban, 2008). Josephus explicitly describes the expense of and investment made in the harbor's construction. Excavations have since supported these grandiose statements, revealing bulk raw building materials that traveled long journeys before arriving in Caesarea (Votruba, 2007). For example, chemical analysis of the volcanic ash (‘pozzolana’) used for producing the fast-drying hydraulic cement shows that the ash was brought from Vesuvius (Brandon, 1996; Hohlfelder et al., 2007), while the underlying cobble and rubble beds beneath the cement-filled caissons show non-local mineralogies common to Turkey, Cyprus, and parts of Greece. The wood used for the caisson frames, as was common practice in shipbuilding of the time, came from the cedar forests of Lebanon (Votruba, 2007).

However, despite the significant investment and durability of the cement used in the construction process (Jackson et al., 2012), the overall state of the harbor had significantly deteriorated by the end of the 2nd century CE, and probably even earlier, according to radiocarbon-dated sedimentological evidence showing a shift from a low-energy, harbor environment to an open-water exposed, unprotected environment during that period (Reinhardt and Raban, 1999; Reinhardt et al., 1994). Throughout the 1990s, the generally accepted presumption arising from these studies was that the harbor experienced its demise due to some combination of earthquake-related liquefaction, with some credence also given to the possibility of related tsunami, though without clear markers then to support such a hypothesis.

Caesarea harbor phases, from initial construction to the present, have been reconstructed using sedimentological, geophysical (i.e., magnetometry), and archaeological surveys (Reinhardt et al., 1994; Reinhardt and Raban, 1999, 2008; Boyce et al., 2009). The most recent summary (Reinhardt and Raban, 2008) suggests six such phases, summarized as follows:
  1. Initial construction, 1st century CE
  2. Destruction, 1–2nd century CE
  3. Unprotected (exposed to open sea; no intact harbor features), 3–4th century CE
  4. Natural/unimproved harbor, 4–6th century CE
  5. Sand infilling, 6th century CE
  6. Renovation/destruction, 6–11th century CE
Unfortunately, the foregoing summary remains vague regarding causation, as it predates later findings (Goodman-Tchernov et al., 2009) that bring to light evidence for tsunami events in both the Byzantine (4–6th c. CE) and Early Islamic (7th–8th c. CE) periods, as well as confirming an earlier suggestion of another 2nd century CE wave-based event (Reinhardt et al., 2006).

Previous geophysical research on the Caesarea Maritima harbor has included both seismic and magnetic surveys (Mart and Perecman, 1996; Boyce et al., 2004, 2009). Boyce et al. (2004) conducted a magnetic survey with the aim of determining the feasibility of using magnetic signatures to map and define the concrete installations of the harbor, as the pozzolana cement used by the Romans was iron-rich. Although the high resistivity of the kurkar bedrock proved to be challenging, the overall form of the foundations of the harbor, particularly the individual caisson forms, was discernible. Due to the significant difference between the near-coastal harbor features, which remain at their correct elevation relative to sea level, and offshore harbor features, which are now submerged up to 5 m depth, earlier work had suggested that movement along a shore-parallel fault, which became active following construction of the harbor, could be responsible for the modern elevation change (Mart and Perecman, 1996). As a result, for many years afterward, theoretical north–south trending fault lines remained on maps of Caesarea. However, after failed attempts to recognize these features in the field through additional geophysical mapping, along with jet-probe surveys of the sediments with associated seafloor excavations (Raban, 2008), such structures are now rarely included. Instead, the observed coast-parallel offset in elevation is now presumed to relate more directly to the classic challenges faced when constructing directly on bedrock versus adjacent (offshore) unconsolidated sediments. Areas of the harbor constructed seaward of the firm kurkar bedrock foundation were likely more susceptible to liquefaction, undercutting, scouring and erosion, promoting subsidence of harbor features farther offshore, whether by storms, earthquakes, or tsunamis.

Historical evidence for tsunamis in the eastern Mediterranean supports a minimum of 21 events, three referring to the city of Caesarea directly (115 CE, 551 CE and 1202 CE; Shalem, 1956; Amiran et al., 1994). Archaeologists have been aware of these events for decades (see discussion in Dey et al., 2014), but they have lacked the comparative tools or reference data to ascribe particular deposits (onshore or offshore) to tsunami-derived causes. As a result, alternative explanations for these seemingly anomalous deposits found in archaeological sites have been put forward. For example, laterally extensive shell beds encountered in terrestrial excavations in Caesarea, which could be evidence of tsunamigenic origin, have been previously ascribed to be the result either of dredging activities or as construction fill (Neev and Emery, 1989). Tsunami sedimentological research has also advanced, particularly in response to the destructive tsunamis of Sumatra 2004, Java 2009, Chile 2010 and Tohoku-Oki 2011 (e.g., Szczuciński, 2011; Goff et al., 2012; Pilarczyk and Reinhardt, 2012; Pilarczyk et al., 2012; Goto et al., 2014). As a result, there is now an extensive, robust body of comparative data for interpreting and understanding historical, prehistorical and paleo-tsunamigenic deposits (e.g., Bourgeois et al., 1988; Goff et al., 2012), which did not exist a decade ago.

This increase in knowledge has led to the recognition of more such tsunamigenic deposits worldwide, both in the archaeological and geological records (e.g., Pareschi et al., 2007; Vött et al., 2009; de Martini et al., 2010; Yawsangratt et al., 2011; Marco et al., 2014, but see also criticism of this approach in Galili et al., 2008; Morhange et al., 2014). However, despite this increased awareness, the number of tsunamigenic sedimentological deposits documented from the Levantine Sea region, and other parts of the Eastern Mediterranean, still only begins to approach the number of events recorded in the written record (Papadopoulos et al., 2014), suggesting that discovery of these deposits in this historically important part of the world remains incomplete.

Research on the demise of Caesarea's harbor (Reinhardt et al., 1994; Reinhardt and Raban, 1999) agrees generally that the timing of initial major deterioration had occurred at least by the end of the 2nd century CE (see also Raban, 1992; Raban, 1995; Reinhardt and Raban, 2008; see Hohlfelder, 2000, for alternate timing). Evidence to support the role of tsunamis in this initial damage takes the form of laterally extensive sedimentary horizons with interpreted tsunamigenic characteristics (details follow below) recorded offshore, as well as reviews of archaeological reports demonstrating the presence of corresponding deposits on land (Reinhardt et al., 2006; Goodman-Tchernov et al., 2009; Dey and Goodman-Tchernov, 2010; Dey et al., 2014).

Reinhardt et al. (2006) have characterized a tsunami deposit, found in an excavation trench (Area ‘W’, see Fig. 1C) outside of the ancient harbor, based on the presence of imbricated allochthonous shells (predominately Glycymeris violescens), with radiometric ages (1st c. BCE to 2nd c. CE) corresponding with a historically documented tsunami event at 115 CE (Shalem, 1956). Other defining characteristics of this deposit include an erosional basal contact, and mixing of included clast sizes. Goodman-Tchernov et al. (2009) have also investigated the lateral extent of this reported horizon, and identified its continuation, as well as the presence of additional interpreted but distinct tsunami horizons, based on the same criteria and an additional seven tsunami-related indicators: micropaleontological assemblage, fining-upward sequence, tilted marine installations, larger standard deviation of particle size distributions (relative to typical background), out-of-place household items, rip-up harbor mud clasts, and rafted terrestrial organic material. Reports from terrestrial archaeological excavation reports pre-dating the Reinhardt et al. (2006) initial recognition of these tsunami deposits were also revisited by Goodman-Tchernov et al. (2009) to determine whether other horizons containing possible tsunami-related inclusions had been described in the literature but not interpreted as such. Their realization was that a wide range of distinctive stratigraphic evidence for tsunami-related deposits was present. Other sorts of interpretations had included construction fill or dredging refuse dump, but these were refuted in light of new tsunami characterizations (Dey and Goodman, 2010; Dey et al., 2014). In this paper, regional high-resolution seismic profiling offshore the harbor mouth of Caesarea is combined with ongoing marine archaeological investigations to show the regional impact of multiple tsunamis on both this harbor and the adjacent coastline over the past two millennia
.

1.3. Offshore tsunami deposits

Generally speaking, the near offshore environment has not been heavily mined for tsunami evidence. While tsunami-related studies have increased exponentially in the past decade, there are far fewer studies that present shallow offshore finds. In their summary of the state of research in paleotsunami deposits Rhodes et al. (2006) asked, “Does a record of paleotsunamis exist in the near offshore stratigraphic record?”. By that time, Vandenbergh et al. (2003) had demonstrated the presence of shallow offshore deposits using both geophysical survey and coring in NW Java, Indonesia and Abrantes et al. (2005) described events correlatable to sediment core horizons in Lisbon, Portugal. Since then, a few studies of past and recent tsunami events and modeling have answered Rhodes' question in the affirmative as well. Some examples beyond the work in Caesarea (Reinhardt et al., 2006; Goodman-Tchernov et al., 2009, Dey and Goodman 2010, Dey et al. 2014) include cores collected from Augusta Bay, Italy (de Martini et al., 2010; Smedile et al., 2012), offshore boulders mapped in western Banda Aceh, Indonesia (Paris et al., 2009), Weiss and Bahlburg's (2006) modeling predictions suggesting the presence of deposits in the shallow offshore. The near offshore environment is still more poorly understood relative to terrestrial coastal areas.

4. Discussion

The interpretation of three sub-seafloor reflectors mapped offshore of Caesarea (Fig. 3) conclude with the presence of distinctive and unique coastal structural configurations at the time of past tsunami events. The mapping suggests regionally significant impedance contrasts, that were interpreted here as marking the last/uppermost expression of known tsunami deposits previously sampled, analyzed and interpreted on this margin (Fig. 4). In all cases, we assume, and this is supported by modern studies elsewhere (Paris et al., 2009), that immediately following any tsunami, complex processes of alteration and erosion occur, particularly in depths exposed to storm activity and other coastal processes (e.g., long shore transport). In this part of the Mediterranean, these tsunami deposits, or what part of them is preserved after exposure to later storm and long-shore transport effects, are buried under Nile River–derived sands. Therefore, we suspect that the reflector maps of the two subsurface reflectors (Fig. 6B, C) does not give a reading of what the sea bottom looked like immediately following the tsunami, but at the time of the tsunamite’s eventual burial, which could be a matter of decades or more. Therefore, the apparent drainage features we observe are probably only preserved remnants of tsunami backwash features which, at the time of their formation, would have been even more distinctive and pronounced, as is true in modern analogues (Bahlburg and Spiske, 2012; Feldens et al., 2009; Hori et al., 2007; Paris et al., 2009). Each event has a unique signature that relates to the state of the coastline and the structures present at that time.

The deepest reflector, ‘C’ (Fig. 3B), which is associated here with what is left of the Santorini-age tsunamite, is not sufficiently preserved offshore Caesarea to identify except in topographic lows in the kurkar topography (Fig. 3B), and in deeper water. The unaltered coastline in this area is high-energy, with little natural protection, which is one of the reasons that specialized engineering methods were required to create the Caesarea harbor. Therefore, prior to the harbor’s construction, at the time of the Santorini-age event (Fig. 4), tsunami deposits in shallow water would not have had a good chance for preservation due to their exposure to the open sea, but were more likely redistributed and transported during storms; we also see such storm-related redistribution today. In contrast, later events following the construction of the harbor have a greater chance of preserving due to the more protected nature within the harbor area, even if only in relative terms, from the full force of incoming storms. This is observable today during storms in which the waves are noticeably attenuated within the semi-protected harbor bay, despite the harbor’s generally dilapidated condition. Sedimentological evidence clearly shows the presence of the Santorini horizon in water depths > 10 m (Fig. 4). In area ‘W’ (Fig. 1C; 4, upper right) the stratigraphic sequence includes a major hiatus (~3 kyr of missing sediment), which includes the level at which the Santorini horizon would have been expected. We expect such a hiatus in area W, as it is located just outside the harbor entrance, and would have experienced focused outgoing flow capable of substantial erosion and scouring during the back-channeling phase of a tsunami. In addition, because harbors are known to intensify the effects of tsunamis, any Santorini-aged tsunami deposits in shallow water that survived until the construction of the harbor would have been vulnerable to further erasure following the first of the post-harbor construction tsunami events (Fig. 4).

Reflector B’s surface morphology includes a main channel complex that corresponds approximately with the position of the harbor entrance (Fig. 6C). Because Caesarea’s harbor is believed to have been in good condition at the time of the 2nd century tsunami, the incoming wave must have encountered an intact and standing outer harbor mole, which would have forced abrupt shoaling of the incoming wave, scouring deeply the area immediately outside the harbor, while also breaching the tops of man-made features. Incoming wave inundation must also have run up within the harbor, as well as along the coastline north and south. However, during subsequent retreat of the wave, that outflowing water would have concentrated through the harbor mouth, between the reinforced moles (Fig. 2), preferentially scouring and eroding the region immediately outside the harbor entrance and depositing larger deposits farther offshore, as is evident in the ~80 cm 2nd century deposit in Area W (Reinhardt et al., 2006). Estimating the velocity of the flow exiting the harbor mouth during the 115 CE event is possible, because archaeological evidence exists for the movement and toppling of an artificial island that stood at the harbor entrance at that time (Raban, 2008). During excavations there in the late 1990s, concrete was exposed and a vertical contact between cement layers of different fabrics was recorded. These cement layers are a remnant of the construction process, during which different cement mixes were used at different phases of filling the wooden caissons (Brandon, 1996, Hohfelder et al., 2007). At the time of construction, after the cement cured, the different concretes layers lay horizontal upon one another; therefore, any shift from the original position at construction can be identified due to the offset of that horizontal contact. In the case of the tower, the near-vertical contact indicates at least a 90° shift of the caisson after the harbor was completed. It was also observed that no wood was preserved on any outer surface of the island, whereas typically protected, unexposed sides of the caissons included some preserved wood, again suggesting that all sides of the island, which was essentially once a wood-faced concrete cube, had been exposed on all sides fully to the elements at some point of time, a situation only possible with the turning of the caisson. Artifacts found around the base of the toppled tower post-date the 1st century CE, with the earliest coin found aged at 144 CE. These deposits are not beneath the tower, but rather along the edges of the tower within the typical scouring areas where debris is regularly trapped in harbor entrances. Excavations did not tunnel fully below the towers due to safety concerns. Such artifacts might provide an age maximum for the timing of the tower’s collapse, so the observed damage best correlates with the historic tsunami a few decades earlier in 115 CE. As the minimum size of this island was at least 25 m³, and as its concrete has an estimated minimum density of ~2400 kg/m³, its estimated weight should exceed 60 metric tons. Toppling such an island would have required significant force, and is analogous to damage that has been recorded to concrete harbor structures recently during the 2011 Tohoku-Oki tsunami in northern Japan events (Fig. 7, Ewing et al., 2013).

We hypothesize that the shallower subsurface reflector ‘A’ is the buried surface formed by backflow associated with the 8th century CE (possibly 749 CE) tsunami; this surface could also represent a composite with the 6th century CE (551 CE) event. We suggest that the multiple, distributed channels observed in that reflector’s surface morphology (Fig. 6B) represent a complex back-channeling product produced by the less-organized/more degraded character of the harbor at that time. The Byzantine Era (4th–7th c. CE) was a busy time for Caesarea commercially, but with the exception of a 500 CE renovation, the harbor consisted primarily of the intermediate harbor (Fig. 1D) with very little, if any, surface presence of the outer harbor mole/jetty complex (Figs. 1D, 2; Reinhardt and Raban, 1999). Presuming that the map of reflector “A” gives us the ~post-8th century event state of the coastal sea bottom, the harbor would have been in an even more degraded condition through the Early Islamic (7th–11th c. CE) period, with multiple disorganized approaches rather than a single cohesive entrance (Fig. 6B, right). Recently this chaotic character of the outer harbor at that time was reinforced with the discovery of thousands of gold coins dating to the 10–11th century that were presumably part of a shipwreck discovered on top of the submerged harbor in a depth of only 7.5 m, which could only be possible if that area was not a cohesive harbor at the time. Ship ballast concentrations and refuse have been recognized outside the harbor in a roughly shore-parallel, elongated oval shape that agrees with the pattern of debris that would be expected in an anchoring refuge for commercial transactions, given prevalent wind patterns and typical anchoring scope ratios (Boyce et al., 2009). This overlying refuse may be deposited immediately above the two tsunami horizons in question, suggesting that whatever condition the harbor was in prior to the 749/551 CE events, it was even more heavily compromised afterwards. As a result, by the 6th century CE, commercial ships likely had to anchor offshore as a standard practice.

Recently, in continuing efforts to link terrestrial archaeological stratigraphy to the offshore sequence, evidence has been gathered to suggest that there are two distinct stratigraphic horizons with tsunamigenic features, one dating to the late Byzantine (~6th century CE) and the second to the Early Islamic (8th century CE) periods (Fig. 4). Much of this evidence comprises of shell layers described in the terrestrial excavations that were previously interpreted as dredge debris (see Dey et al., 2014 for detailed discussion). However, thus far, only one offshore layer has been identified (Fig. 4). The original dating of that offshore horizon (Goodman-Tchernov et al., 2009; Fig. 4) was limited to a few sherds of ceramics that were ceramic types that remained in use over a long period that included the late Byzantine period and into the Early Islamic era (~5–8th c. CE), and only one radiocarbon date has been obtained from shell material immediately above the horizon. After a more detailed review of the dating methods used for that horizon in previous studies, recent finds from shallow (< 3 m) water excavations, and review of archaeological reports from the hippodrome coastal area (Dey et al. 2014) we suggest that the single horizon is actually the result of two separate tsunami events that occurred relatively close in time (~200 years), resulting in a single deposit. An upper date of 900–1050 CE (radiocarbon, Goodman-Tchernov et al., 2009) from the horizon immediately above the deposit, gives an upper limit for the tsunamite age, but also supports the possibility that both 6th and 8th century CE tsunami events contributed to the preserved horizon
.

Following any tsunami event, sediments eroded and redeposited by the waves are exposed to later erosional and depositional processes. For Caesarea, the normal depositional regime, dominated by sandy sediments from the Nile River to the south, typically provides a positive sediment budget necessary for burying the tsunamite. However, short intervals between tsunami events means that less inter-event sediment is available to bury and preserve the underlying tsunamites. If a buried tsunamite is exposed and eroded during a later tsunami, then that material can be mixed and redeposited together with the later event, resulting in a single horizon.

Evidence for such mixing offshore of Caesarea exists in multiple forms. First, archaeological descriptions demonstrate the presence of tsunamigenic deposits on land south of the harbor, within the adjacent hippodrome area (see Figs. 1 and 2), of both 6th century A.D. and 8th century A.D. deposits (Dey and Goodman, 2010; Dey et al., 2014). In excavations of the shallow intermediate harbor (TN area, Fig. 1C; Reinhardt and Raban, 2008), there is an extensive deposit of mixed (Early Islamic–Byzantine, 4th to 8th century CE) refuse, ranging from high-value intricate items of varying erosion state and exposure—suggesting broad mixing of typical harbor refuse (e.g., broken amphora/pots) and newly introduced, undamaged domestic wares and personal items (e.g., intricate hair combs, fine sections of Islamic coins, statuette, a satchel of copper coins). Unlike other harbor deposits, these materials are of broad origin (domestic, commercial, religious), value range and preservation state, suggesting the kind of non-deliberate and rapid burial a tsunami event would produce. In addition, because the ages of the ceramics found in this excavation range from Early Islamic to late Byzantine (6th through 8th centuries CE), no distinctive stratigraphy offshore today separates what may have been two distinct tsunami events.

The expression of the different horizons in this offshore seismic survey is only possible due to the significant acoustic contrast in the physical properties between the tsunami event layers vs. the background, non-tsunami sediments (Fig. 5). In the case of Caesarea, the background Nile River–derived sands are especially homogenous (siliciclastic, quartz-rich fine sands with a highly conservative mode value of ~169 μm), while the tsunamigenic layers consist of a range of grain sizes and inclusions of varying materials with far wider-ranging physical properties (shell, broken kurkar cobbles, foreign ballast, pottery, etc.). As a result, Caesarea may represent ideal conditions for the application of geophysical methods to tsunamite identification in the coastal zone. Other areas of the Mediterranean, and the world, where coasts with more meandering geomorphological features likely exhibit more variations and micro-environments in their natural background conditions, tsunamite definition is likely to be more problematic. Nonetheless, we feel that our results merit the effort to attempt similar merged mapping and archaeological excavations/sampling elsewhere.

5. Conclusions

The results of the high-resolution seismic survey of Caesarea support previous studies that have argued for the presence of laterally extensive tsunamigenic deposits in and around that ancient harbor complex. Santorini-age tsunami deposits are present, but not everywhere identifiable. The earlier interpretation that the ancient harbor of Caesarea was relatively intact at the time of the first historically documented tsunami that would have impacted it, ~1–2nd century, possibly 115 CE, is supported by the presence of pronounced (backwash) channels in association with the entrance to the ancient harbor. In contrast, the harbor's appearance was much degraded by the time of a known 8th century tsunami (749 CE), which is emphasized by the presence of a series of preserved remnant channels, testifying to multiple backwash paths. These preserved paleo-bathymetric features could be recognized at other archaeological sites and may provide a new preserved indicator for ancient tsunamis, further reinforcing the usefulness of the offshore record, particularly relative to the relatively quickly altered and erased terrestrial record (Szczuciński, 2011).

Caesarea, an ancient urban harbor city with a concrete harbor comparable to many harbors of today, also provides insight into the effects of tsunamis on harbors and the nature of preserved deposits in and around them. We suggest that the intensification and magnification of tsunamis within harbors could provide an additional dataset for targeting and identifying non-documented tsunamis and improving the understanding of their impact on harbor structures, enhancing and expanding on the tsunami catalogues, as well as better understanding broader near and far-field effects elsewhere. A multitude of harbor sites both nearby (e.g., Tyre, Sidon, and Alexandria) and worldwide could contain these useful deposits.

Goodman-Tchernov et al. (2009)

Abstract

A sedimentary deposit on the continental shelf off Caesarea Maritima, Israel, is identified, dated, and attributed to tsunami waves produced during the Late Bronze Age (ca. 1630–1550 B.C.E.) eruption of Santorini, Greece. The sheet-like deposit was found as a layer as much as 40 cm thick in four cores collected from 10 to 20 m water depths. Particle-size distribution, planar bedding, shell taphocoenosis, dating (radiocarbon, optically stimulated luminescence, and pottery), and comparison of the horizon to more recent tsunamigenic layers distinguish it from normal storm and typical marine conditions across a wide (>1 km²) lateral area. The presence of this deposit is evidence that tsunami waves from the Santorini eruption radiated throughout the Eastern Mediterranean Sea, affecting the coastal people living there. Dates for the tsunami deposit bracket both the so-called “high” and “low” chronology for the Santorini eruption. In addition to resolving the question of the extent of tsunami impact from the Santorini eruption, the research presented also provides a new means of discovering, identifying, and studying continuous records of paleotsunami deposits in the upper shelf coastal environment. The latter is key to understanding past events, better interpreting sedimentological records, and creating stronger models for understanding tsunami propagation, coastal management, and hazard preparation worldwide.

Introduction

The Plinian eruption of Santorini (Thera, ca. 1630–1550 B.C.E.; Friedrich et al., 2006; Manning et al., 2006), Greece, in the Late Bronze Age, at an estimated 7.1 on the Volcanic Explosivity Index (McCoy et al., 2000), was one of the largest eruptions in human antiquity (Friedrich et al., 2006; Manning et al., 2006; McCoy and Heiken, 2000; Sigurdsson et al., 2006). The extent to which the eruption precipitated tsunami waves has long been debated, as has the question of the range and magnitude attained by such waves (Yokoyama, 1978).

The position that the Santorini eruption resulted in tsunami waves is based on the reporting of tsunami deposits along coastal areas of Greece and Turkey (Fig. 1A) and comparison of that event with tsunami waves associated with historic eruptions that involved similar eruptive mechanisms (Manning et al., 2006; McCoy and Heiken, 2000; Sigurdsson et al., 2006; Yokoyama, 1978). Computer models incorporating this evidence have shown that near-field and far-field wave amplitudes were significant, with maximum wave amplitudes of 26 m and inland inundation to 200 m along the coast of Crete (Bruins et al., 2008; Dominey-Howes et al., 2006; McCoy and Heiken, 2000; McCoy et al., 2000; Yokoyama, 1978). If the waves propagated from the event were strong enough to reach the coast of Israel, 1000 km away, then presumably other Late Bronze Age coastal sites across the Eastern Mediterranean littoral will likely have been affected as well.

Tsunami literature is full of sedimentary studies of post-tsunami deposits; however, these studies are mainly terrestrial and break off abruptly at the coastline, or at best the low tide mark (Choowong et al., 2008; Hawkes et al., 2007). It has been postulated (Weiss and Bahlburg, 2006), and is shown in this study, that the offshore upper shelf environment can contain preserved tsunami deposits. Traditionally, marine sediments discovered in terrestrial deposits have been used to identify tsunami deposits and assess tsunami magnitude (Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Jankaew et al., 2008; Nanayama et al., 2003). Preserved upper shelf marine tsunami deposits are a new source for field-based tsunami evidence (Reinhardt et al., 2006). The general exclusion of these types of deposits from past literature (with the exception of Krakatau; van den Bergh et al., 2003) is likely due to the difficulty of differentiating tsunamigenic layers from storm signatures and subtle mixing in the nearshore zone.

Method

Four sediment cores were collected (Fig. DR1 in the GSA Data Repository1) and one area (area W) was re-excavated with dredges in the sandy upper shoreface (~15 to 20 m below msl) offshore of Caesarea (Fig. 1B), in order to
  1. determine the lateral extent of a previously identified second century (C.E.) tsunamite (Reinhardt et al., 2006)
  2. test hypotheses related to defining and identifying tsunami deposits using multiproxy methods
  3. differentiate the deposit from possible archaeological anthropogenic sedimentation
  4. determine the appearance of a tsunami deposit sequence seaward of the coastline
The major aims of the analysis were to determine sediment characteristics (i.e., micropaleontology, granulometry) in a known tsunamite as a means of differentiating between normal large storm cycles and tsunamis, and identifying the maximum extent of the tsunamigenic deposit, based on established tsunamite characteristics (Bruins et al., 2008; Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Donato et al., 2008; Morton et al., 2007; Reinhardt et al., 2006).

The study presumed that tsunamite horizons would be areally extensive and thus visible in a majority of the cores, and hypothesized that the deposits would grow gradually thinner seaward. Hence, at greater depths the deposits would be expected to become less visible, with fewer tsunamigenic indicators. The chronology of the cores was determined using ceramic finds, radiocarbon, and optically stimulated luminescence (OSL) dating (Tables DR1 and DR3). Local sea-level change (Sivan et al., 2001) would not have dramatically altered the cores’ positions relative to water depth (Fig. 2).

Tsunamigenic indicators, as defined by previous tsunami studies (Bruins et al., 2008; Dawson and Stewart, 2007; Dominey-Howes et al., 2006; Donato et al., 2008; Morton et al., 2007; Reinhardt et al., 2006) (Figs. 2 and 3), included erosional lower contacts, fining-upward particle-size distribution, imbrication of inclusions, individual or groups of molluscs, mixed wear and poor sorting of molluscs, change or distinctive microfossil assemblage (foraminifera), rip-up clasts, household goods and high-value anthropogenic cultural material misplaced in marine context, rafted organics or pumice, unidirectional tilting of marine installations, and well-rounded beach zone pebbles in deeper contexts. Based on comparisons of particle-size distributions of known events within the cores (Fig. 4), a unique sorting based on particle-size distribution was also recognized as a tsunamigenic indicator at this location. Sediment characteristics of the tsunamigenic and intermediary deposits were described and compared.

Results And Discussion

A minimum of one and a maximum of three tsunamigenic horizons were identified in each of the cores (Figs. 2 and 3; Figs. DR2–DR6). Event 1, ca. 1.5 ka ago, corresponds chronologically with a historically documented event of 551 C.E. [JW: Later work suggested this deposit was from a mid-8th century CE tsunami and if 551 CE tsunamigenic deposits were present, they were reworked by the mid-8th century CE event] (Amiran et al., 1994; Mart and Perecman, 1996; Salamon et al., 2007); it is well represented across all of the cores and trenches, and is also present in the findings of previous archaeological excavations (Raban, 2008; Reinhardt and Raban, 2008, 1999; Reinhardt et al., 2006, 1994, 1998), where this horizon was interpreted solely as isolated deposits of jettisoned archaeological materials, or a storm layer (Boyce et al., 2009; Reinhardt et al., 2006). The new results complement the previous interpretation that onloading and offloading of goods occurred outside of the harbor (Boyce et al., 2009), particularly in the light of possible tsunami-related damage to the harbor. Tsunamite indicators of event 2, ca. 2 ka ago, which correspond with an historical event of 115 C.E. (Amiran et al., 1994; Kortekaas and Dawson, 2007; Mart and Perecman, 1996), are visible in all of the cores. Event 3, OSL and radiocarbon dated to 3630–3410 cal (calibrated) yr B.P., and thus to the period of the Santorini eruption, was identified in cores 1–4. The Santorini-age event differs from the more recent events in the amount of archaeologically related materials in the deposits (Fig. 3B). During events 1 and 2, Caesarea was already built, and therefore the horizon is rich with related anthropogenic debris from the well-populated port city, whereas no major city is known to have existed at that site during event 3 (Late Bronze Age). Therefore, many of the tsunamigenic indicators present during events 1 and 2 are irrelevant for event 3.

Distinguishing between storm and tsunami deposits has long been a central challenge within tsunami research. Tsunami and storm waves differ in the depth to which they can disturb the sea bottom; as water depth increases, storm influence becomes less apparent, while tsunami influence remains (Weiss and Bahlburg, 2006), and these influences can be visible in particle-size distributions. Contour-map plotting of particle-size distributions visually represents differences in distribution more clearly than with conventional means of data expression (Donato et al., 2008; Beierle et al., 2002), and here provides a very useful tool for differentiating between typical storm events and tsunami events (see Fig. 4 and Figs. DR7 and DR8). For example, particle-size distribution results from the tsunamigenic horizons of core 1 (14.3 m water depth) are characterized by a wider range of grain sizes and poor sorting relative to nontsunamigenic horizons. In addition, large storm horizons are visible between the tsunamigenic events, characterized by a range of particle sizes greater than nontsunamigenic horizons, but more limited than tsunamigenic horizons. In comparison to core 1, the storm deposits particle-size distribution signatures in core 2 (20 m water depth) are nearly nonexistent, while the chronologically correlated tsunamigenic horizons are still visMode Particle Sizeible. Thus, the use of particle-size distribution analysis for interpretation makes it possible to recognize tsunamigenic horizons that would be otherwise untraceable. In addition, multivariable K-cluster analysis of the particle size distributions from core 1 ( 15 m) demonstrated that the tsunamigenic horizons clustered independently, while the storm horizons remained within the range of nontsunamigenic horizons (Figs. DR7 and DR8).

Area W (Figs. 1–3) lacked evidence for the Santorini event due to a pronounced disconformity represented by a missing section of at least 2 ka worth of deposits (Reinhardt et al., 2006). This may be the result of erosion and scouring against the harbor structure during the Roman period tsunami (event 2). In the deeper cores, outside the influence of the harbor structure, traces of the Roman period event remained. In the terrestrial and nearshore zone, no data are available for Santorini-age horizons because this exceeded the depths of the archaeological excavations. There are two claims of Santorini-derived deposits from the Tel Aviv area (Neev et al., 1987; Pfannenstiel, 1960) that have been disregarded as unreliable due to poor dating and weak, single variable evidence (rafted pumice, high terrace shell bed). In light of these new findings, these previous claims may be worth revisiting.

Conclusions

Tsunami horizons coincident with the Santorini eruption were identified from upper shelf submerged sediment cores in the Eastern Mediterranean offshore from Caesarea, Israel, based on the correlation of well-dated horizons with tsunamigenic indicators. The continental shelf contains a wealth of undisturbed deposits to better inform and complete the paleotsunami record worldwide, particularly for the many areas where shelf bathymetry similar to that of the Eastern Mediterranean exists. These findings constitute the most comprehensive evidence to date that the tsunami event precipitated by the eruption of Santorini reached the maximum extent of the Eastern Mediterranean.

Textual Seismic Effects
Eusebius Mystery Quake - 126-130 CE

Effect Location Image(s) Description
  • Collapsed Walls                 
Caesarea
  • "Nicopolis and Caesarea were ruined in an earthquake" - Eusebius

  • "An 438 - In that year there was an earthquake: Nicopolis and Caesarea were overthrown. From the Chronological Canon of Andronicus." - Elias of Nisibis

363 CE Cyril Quake

Effect Location Image(s) Description
  • Houses Destroyed           
  • Collapsed Walls
Caesarea

749 CE Sabbatical Year Earthquake - Holy Desert Quake

Effect Location Image(s) Description
  • Places Devastated (Collapsed Walls)
  • Fatalities
Coastal Palestine
  • Agapius of Manbij, while referring to the Holy Desert Quake of the Sabbatical Year sequence. wrote that "there was a violent earthquake on the coast of the sea of Palestine" and "many places were devastated and many people perished."

Archaeoseismic and Tsunamigenic Effects
Caesarea Harbor Earthquake and/or Tsunami - Late 1st - 2nd century CE

Effect Location Image(s) Description
Liquefaction and Subsidence outer harbor breakwater



Description

  • The first to second century A.D. basal rubble unit (L4) was found on the carbonate cemented sandstone bedrock (locally known as kurkar) and was characteristic of a high-energy water deposit (Fig. 2). The rubble was framework supported with little surrounding matrix and composed mainly of cobble-sized material, which was well rounded, heavily encrusted (e.g., bryozoans, calcareous algae), and bored (Lithophaga lithophaga, Cliona) on its upper surface. The rubble had variable lithologies including basalts, gabbros, and dolomites, all of which are absent on the Israeli coastal plain and were likely transported to the site as ship ballast (probably from Cyprus). The surrounding matrix was composed of shell material (mainly Glycymeris insubricus), pebbles, and coarse sand. The pottery sherds found in this unit were well rounded, encrusted, and dated to the first to second century A.D. The date for this unit and its sedimentological characters clearly records the existence of high-energy conditions within the inner harbor about 100-200 yr after the harbor was built. This evidence of high-energy water conditions indicates that the outer harbor breakwaters must have been severely degraded by this time to allow waves to penetrate the inner confines of the harbor (Fig. 3, A and B).

    Indication of the rapid destruction of the outer harbor breakwaters toward the end of the first century A.D. is derived from additional data recovered from the outer harbor. In the 1993 season, a late first century A.D. shipwreck was found on the southern submerged breakwater. The merchant ship was carrying lead ingots that were narrowly dated to A.D. 83-96 based on the inscription "IMP.DOMIT.CAESARIS.AUG.GER." which refers to the Roman Emperor Domitianus (Raban, 1999). The wreck was positioned on the harbor breakwater, indicating that this portion of the structure must have been submerged to allow a ship to run-up and founder on top (Raban, 1999; Fig. 3B). Because Josephus praised the harbor in grand terms and referred to it as a functioning entity around A.D. 75-79, and yet portions of the breakwater were submerged by A.D. 83-96, we conclude that there was a rapid deterioration and submergence of the harbor, probably through seismic activity.
    - Reinhardt and Raban (1999)

  • The submergence of the outer harbor break-waters at the end of the first century A.D. could have also been due to seismic liquefaction of the sediment. Excavations have shown that the harbor breakwaters were constructed on well-sorted sand that could have undergone liquefaction with seismic activity. In many instances the caissons are tilted (15°-20° from horizontal; Raban et al., 1999a) and at different elevations, which could be due to differential settling (area K; Fig. 1). However, the tilting could also be due to undercutting by current scour from large-scale storms (or tsunamis) and not exclusively seismic activity. Our data from the inner harbor cannot definitively ascribe the destruction of the harbor at the end of the first century A.D. to a seismic event, although some of the data support this conclusion. However, regardless of the exact mechanism, our sedimentological evidence from the inner harbor and the remains of the late first century A.D. shipwreck indicate that the submergence of the outer breakwater occurred early in the life of the harbor and was more rapid and extensive than previously thought. - Reinhardt and Raban (1999)

Tsunami Offshore Caesarea


Description

  • Although Goodman-Tchernov and Austin (2015) and earlier researchers associated a 1st - 2nd century CE tsunamite deposit from offshore Caesarea with the Trajan quake of ~115 CE, this association is unlikely. Salamon et al (2011) noted that the presence of a tsunami far south of the supposed epicenter of the Trajan Quake does not fit the usual pattern of tsunamis on the Israeli coast where most tsunamis which hit the coast were generated by ruptures more or less opposite to the coast (e.g. from the Cypriot and Hellenic Arcs). While Salamon et al (2011) suggested a storm surge as a possibility, the work of Goodman-Tchernov and Austin (2015) and earlier publications appears to preclude this as they used a host of indicators to seperate storm surge deposits from tsunamite deposits. I propose that an offshore shelf collapse potentially due to the Incense Road Earthquake of the early 2nd century CE as a likely cause.

  • Goodman-Tchernov and Austin (2015) examined and dated cores taken seaward of the harbor and identified 2 tsunamite deposits (see Tsunamogenic Evidence) including one which dates to to the 1st-2nd century CE. Although, it is tempting to correlate the 1st-2nd century CE tsunamite deposits of Goodman-Tchernov and Austin (2015) to the L4 destruction phase identified in the harbor ( Reinhardt and Raban, 1999), the chronologies presented by Goodman-Tchernov and Austin (2015) suffer from some imprecision due to the usual paucity of dating material that one encounters with cores. Further, the harbor subsidence and breakwater degradation dated by Reinhardt and Raban (1999) may not have been caused by seismic activity. If it was related to seismic activity, the early 2nd century CE Incense Road Quake is a better candidate than the 115 CE Trajan Quake because it would have produced higher intensities in Caesarea.

  • 4.5.2. Sedimentological Findings at Sea Presented as Indicators of a Tsunami

    The core issue in tsunami sedimentology is to distinguish tsunami deposits from beach or storm deposits. Marine fauna and marine deposits found in low-lying, lagoonal water bodies near the coast are often used as paleo tsunami indicators, and so is the presence of large boulders on a rocky coast, away from the sea [42,83,84]. Identifying offshore tsunami deposits is more challenging. It has been less practiced, as there are very few analogies for comparison and it is hard to distinguish them from storm deposits [10,42,83]. A comprehensive study conducted by Mariner et al. [84] analyzed hundreds of published records of tsunami events in the Mediterranean and proposed that 90% of them are problematic and need to be re-examined.

    4.5.3. Outside the Harbor

    At a water depth of 10–12 m offshore, Reinhardt et al. (area W, [42]) identified beds of small angular shell fragments and potsherds dated from the 1st century BCE to the 1st century CE that were overlain by a layer of convex-up-oriented disarticulated bivalve shells. Relying on the fragmentation patterns and stratigraphy of the shells, the authors assumed that these shells could be related to the 115 CE tsunami deposits. Reinhardt et al. [42] also reported on the presence of articulated Glycymeris shells in the tsunami deposit, and suggested that these shells indicate transport from the deeper shelf, as the shallowest habitation depth for these bivalves is 18 m. However, no evidence for the presence of such articulated Glycymeris shells in the discussed deposits have ever been presented or published. Furthermore, Meinis et al. [85] noted that Glycymeris sp. (especially G. insubrica or violescens) were very common along the Israeli coast over long periods. They existed at different depths in a coastal environment (e.g., 8–16 m depth) and even at 200 m water depth. In the Adriatic Sea, their habitat was reported to be at a water depth of 2–40 m [86]. Moreover, Reinhardt et al. [42] give no explanation of how these articulated mollusks survived what they describe as the “ . . . intense wave turbulence, shell-to-shell impacts, and shells striking the harbor moles or bedrock under high wave energy, as generated by a tsunami”. Given the above, there is nothing special in finding G. insubrica in sea bed sediments which are shallower than 18 m. The existence of articulated Glycymeris bivalves in the discased Caesarea deposits is yet to be proven, while the preservation of such articulated shells under a catastrophic tsunami that was assumed to destroy the Roman Harbor, is still to be explained.

    As noted above, it is difficult to distinguish between tsunami and storm deposits [83,84,87,88]. Sakuna et al. [89] noted the difficulty in identifying the shallow-marine tsunami deposits associated with the 2004 Indian Ocean tsunami based on sedimentological evidence. Tamura et al. [10], who study the 2011 tsunami in Japan, concluded that this tsunami (“one of the largest modern tsunamis in the last 1200 years”) did not produce distinct sedimentary records in Sendai Bay. He also stated that there are no established unequivocal criteria for identifying shallow marine tsunami deposits and that it is impossible to identify the associated deposits at sea, since they are not preserved and might have been mixed by storms [10]. Their results agree with the suggestions of Weiss and Bahlburg [90] that the offshore tsunami deposits are unlikely to be preserved at depths shallower than 65 m. In this regard, the deposits identified by Reinhardt et al. [42] as the result of the 115 tsunami that is supposed to have destroyed the harbor, are questionable, as are the three reflected sub-bottom layers identified by Goodman-Tchernov and Austin [9] as tsunami features.
    - Galili et al (2021:16-17,20)

Tsunami Harbor



Description

  • The first to second century A.D. basal rubble unit (L4) was found on the carbonate cemented sandstone bedrock (locally known as kurkar) and was characteristic of a high-energy water deposit (Fig. 2). The rubble was framework supported with little surrounding matrix and composed mainly of cobble-sized material, which was well rounded, heavily encrusted (e.g., bryozoans, calcareous algae), and bored (Lithophaga lithophaga, Cliona) on its upper surface. The rubble had variable lithologies including basalts, gabbros, and dolomites, all of which are absent on the Israeli coastal plain and were likely transported to the site as ship ballast (probably from Cyprus). The surrounding matrix was composed of shell material (mainly Glycymeris insubricus), pebbles, and coarse sand. The pottery sherds found in this unit were well rounded, encrusted, and dated to the first to second century A.D. The date for this unit and its sedimentological characters clearly records the existence of high-energy conditions within the inner harbor about 100-200 yr after the harbor was built. This evidence of high-energy water conditions indicates that the outer harbor breakwaters must have been severely degraded by this time to allow waves to penetrate the inner confines of the harbor (Fig. 3, A and B).

    Indication of the rapid destruction of the outer harbor breakwaters toward the end of the first century A.D. is derived from additional data recovered from the outer harbor. In the 1993 season, a late first century A.D. shipwreck was found on the southern submerged breakwater. The merchant ship was carrying lead ingots that were narrowly dated to A.D. 83-96 based on the inscription "IMP.DOMIT.CAESARIS.AUG.GER." which refers to the Roman Emperor Domitianus (Raban, 1999). The wreck was positioned on the harbor breakwater, indicating that this portion of the structure must have been submerged to allow a ship to run-up and founder on top (Raban, 1999; Fig. 3B). Because Josephus praised the harbor in grand terms and referred to it as a functioning entity around A.D. 75-79, and yet portions of the breakwater were submerged by A.D. 83-96, we conclude that there was a rapid deterioration and submergence of the harbor, probably through seismic activity.
    - Reinhardt and Raban (1999)

  • The submergence of the outer harbor break-waters at the end of the first century A.D. could have also been due to seismic liquefaction of the sediment. Excavations have shown that the harbor breakwaters were constructed on well-sorted sand that could have undergone liquefaction with seismic activity. In many instances the caissons are tilted (15°-20° from horizontal; Raban et al., 1999a) and at different elevations, which could be due to differential settling (area K; Fig. 1). However, the tilting could also be due to undercutting by current scour from large-scale storms (or tsunamis) and not exclusively seismic activity. Our data from the inner harbor cannot definitively ascribe the destruction of the harbor at the end of the first century A.D. to a seismic event, although some of the data support this conclusion. However, regardless of the exact mechanism, our sedimentological evidence from the inner harbor and the remains of the late first century A.D. shipwreck indicate that the submergence of the outer breakwater occurred early in the life of the harbor and was more rapid and extensive than previously thought. - Reinhardt and Raban (1999)

  • 4.5.4. Tsunami Deposits in the Eastern (Inner) Basin

    Excavations in the eastern basin [40] yielded a thin layer of sediments from the 1st to 2nd centuries CE, overlain by a deposit of mixed sediments. They determined that in the 1st century, and evidently up to the 3rd century CE, the prevailing conditions in the eastern basin were of a brackish body of water with good circulation. Thus, the inner harbor seems to have been in use after 115 CE. The mixed sediment deposits discovered in the eastern basin was attributed by Reinhardt and Raban [40] to cleaning and deepening of the harbor in early periods. The proposed main mechanisms for the destruction of the harbor in the study by Reinhardt and Raban [40] were the seismic and tectonic scenarios. Later, however, after reassessing the finds in light of the available new studies on tsunamis, the tectonic and seismic scenarios, as well as the dredging deposit hypothesis, gave way to the 115 CE tsunami scenario [42].

    - Galili et al (2021:16-17,20)

Fallen port architecture harbor


Description

  • At the very deepest spot where the airlift penetrated, beneath huge stone blocks which teetered precariously above the divers' heads, was uncovered a large wooden beam. Beneath its protective cover the divers found the only whole amphora of our dig. This proved to be a second century Roman vessel. The fact that it was found under the tumbled beam and masonry would indicate that these things were catapulted into the sea at the same time. Since there is a strong earthquake recorded in the area of Caesarea in the year A.D. 130 [JW: this refers to the Eusebius Mystery Quake - could also be Incense Road Quake], it may possibly be that the harbor installations of Herod were destroyed at that time. - Fritsch and Ben-Dor (1961)

Coin Hoard Quake - 4th century CE

Effect Location Image(s) Description
  • Collapse?                  
  • Coin Hoard
Synagogue in Field O


  • Raphael and Bijovsky (2014) examined what they describe as "a large hoard of 3,700 copper coins" discovered during excavations of a building that the original excavator, Avi-Yonah, identified as a synagogue. They report that the latest coins in the hoard date to 361 CE, leading them to conclude that the building was destroyed by the 363 CE earthquake and not during the Gallus Revolt (~352 CE).

Vault 2 in Area CV Quake - mid-7th century CE

Effect Location Image(s) Description
  • Vault Collapse     
  • Crushed Pottery
Vault 2 in Area CV



  • From the evidence that was found upon pavement 1047 and on the clay and plaster layers of CV/2, it is clear that Vault 2 and this structure immediately in front of it remained in use up to the point of collapse. The structure appears to have been destroyed suddenly, because collapsed vault and other structural elements crushed pottery vessels that were resting on the floors (figs. 132, 133). No fire was associated with this destruction.

    Vault 2 appears to have collapsed downward, while the frontal arcade structure appears to have fallen both to the west and downward. From the collapsed superstructure of the arcade one can determine that the second storey had a white tesselated floor, probably with a black border, since many fragments of this floor were found in the destruction, including one segment over 3 m. long and at least a meter wide where it emerged from the balk. This segment was upside down, having apparently turned over during the collapse. Above this floor segment many broken roof tiles were found. Thus it appears that the structure was of two storeys and roofed.
    - Raban et al. (1993 v. I:64)

mid-8th century CE Earthquake

Effect Location Image(s) Description
Tsunami                   Offshore Caesarea and Jisr al-Zikra



Description

  • Goodman-Tchernov et al (2009) identified tsunamites in cores taken immediately offshore of the harbor of Caesarea which Goodman-Tchenov and Austin (2015) dated to the 5th - 8th century CE and associated with tsunamis generated by the Beirut Quake of 551 CE and one of the Sabbatical Year Quakes. Although earlier works assigned this 5th - 8th century tsunamite deposit solely to the Beirut Quake of 551 CE, later revisions assigned this offshore deposit mostly to one of the Sabbatical Year Quakes with the suggestion that the Sabbatical Year Quake tsunami deposit contained some reworked tsunamites from the Beirut Quake of 551 CE. The revision may be based on the analysis of re-interpreted landward tsunami deposits (see Fig. 14 above from Galili et. al., 2021) which were dated by Dey et al (2014) to around the time of the Sabbatical Year Quakes. The chronology of the cores was determined using an assemblage of ceramic finds, radiocarbon, and optically stimulated luminescence (OSL) dating. Multiple indicators were used to distinguish tsunami deposits from storm deposits. Particle size distributions were shown to be particularly helpful and reliable. Tsunami horizons were characterized by a wider range of grain sizes and poorer sorting.

    Although efforts to distinguish two tsunami events in the 5th-8th century tsunamogenic deposit by coring in deeper water where an intervening layer, for example, might be present are reported in publications such as Dey et al (2014), this has not yet, to my knowledge, been accomplished. Tsunamogenic evidence for for an event in the mid 8th century CE (e.g. the Holy Desert Quake of the Sabbatical Year Quakes) is better supported than for the 551 CE Beirut Quake although it is possible that both earthquakes generated a tsunami which struck Caesarea.

  • Tyuleneva et. al. (2017) identified what appears to be the same tsunamite in a core (Jisr al-Zarka 6) taken offshore of nearby Jisr al-Zakra. This core was located ~1.5-4.5 km. north of the Caesarea cores. The tsunamite deposit from Jisr al-Zarka was more tightly dated to 658-781 CE (1292-1169 Cal BP) – within the time window for the Holy Desert Quake of the Sabbatical Year Earthquake sequence.

Tsunami Harbor



Description

  • Goodman-Tchernov and Austin (2015) produced a description of a potential tsunami deposit in the shallow intermediate harbor.
    In excavations of the shallow intermediate harbor (TN area, Fig. 1C; Reinhardt and Raban, 2008:155-182 ), there is an extensive deposit of mixed (Early Islamic- Byzantine–4th to 8th century CE) refuse, ranging from high-value intricate items of varying erosion state and exposure—suggesting broad mixing of typical harbor refuse (e.g., broken amphora/pots) and newly introduced, undamaged domestic wares and personal items (e.g., intricate hair combs, fine sections of Islamic coins, statuette, a satchel of copper coins). Unlike other harbor deposits, these materials are of broad origin (domestic, commercial, religious), value range and preservation state, suggesting the kind of non-deliberate and rapid burial a tsunami event would produce. In addition, because the ages of the ceramics found in this excavation range from early Islamic to late Byzantine (6th through 8th centuries CE), no distinctive stratigraphy offshore today separates what may have been two distinct tsunami events.
    Dey and Goodman-Tchernov (2010:278) reported on potential 6th century CE tsunami deposits in the inner and outer harbors.
    The inner harbour was blanketed with a thick deposit of heterogeneous rubble, including bones and other organic remains, pottery, and architectural materials.63 Meanwhile, in the outer harbour, a powerful scouring effect mixed materials datable from the 1st c. B.C. to the 6th c. A.D. into a single, undifferentiated mass, further undermined the breakwaters, and cut a trench into the channel between the outer moles.64 The signs from both the inner and outer harbour are dramatic enough to have led previous commentators already to propose the tsunami of 551 as a possible cause.65

    Footnotes

    [63] Raban 1996, 662; Yule and Barham 1999, 277-78; Reinhardt and Raban 2008, 177-78.

    [64] Reinhardt and Raban 2008, 178-79.

    [65] See, e.g., Raban 1996, 662; Yule and Barham 1999, 277-78; Reinhardt and Raban 2008, 177-78.

Collapsed Vault or Walls, Tsunami, and a Fire Area LL


Fig. 8 (Ad)

Fig. 3

Fig. 2B

Fig. 2C

Fig. 4

Fig. 5

Fig. 8 (Everhardt)
Description

Site LL is located just north of Caesarea's inner harbour. Ad et al (2018) excavated the site which was in use from the Herodian period to the Umayyad period. A storage structure (aka "the warehouse") was identified in the western part of the site which appears to have been constructed in Herodian times and remained in use, as it underwent changes, until the middle of the Umayyad period (~700 CE). After the Islamic conquest of Caesarea (640 CE), rooms were partitioned, floors were raised, construction was added and some of the openings were sealed. Ceramics indicate that the site was abandoned at the end of the 7th century CE after which it suffered two major destruction events before re-occupation occurred in the mid 8th century CE in what was interpreted as Abbasid Strata V (the Abbasid Caliphate began ruling in 750 CE). During the renewed Abbasid occupation, destruction debris were preserved as the builders preferred to level the area and build above the destruction layer(s). The destruction events within Stratum VI (Umayyad) appear to be an earthquake and a tsunami; both likely a result of the the Holy Desert Quake of the Sabbatical Year Quake sequence.

Ad et al (2018) report that during the earthquake event several ceilings collapsed inward, and there was evidence of a fire in the eastern warehouse.1 In the collapse in the corridor, the original order of the courses of the wall or vault could be clearly identified (Fig. 8) adding confidence to a seismic interpretation. During the subsequent tsunami event, a layer of sand and collapsed building stones had accumulated to a height of more than 2 m in Rooms 8–11 in the western warehouse and to a height of 1.5 m in Rooms 12–14 and the corridor of the eastern warehouse. Everhardt et. al. (2023) further examined the destruction deposits by taking cores and radiocarbon samples as well as examining burn evidence and a baulk inside the collapsed corridor.

The cores (C1 and C2) were taken in the collapsed corridor after the Abbasid floor was removed, thus sampling the destruction deposits. See Fig. 1E for location of the cores (and southern baulk) and Fig. 3 for photos and descriptions of the cores and the southern baulk. A ~20 mg. charcoal sample from the top 3 cm of sediment in the Umayyad archaeological fill and one untreated sample of various organic material (~20 mg) from the top 5 cm of the same layer in core C1, as close as possible to the contact with the lower anomalous deposit, were collected for radiocarbon dating. Everhardt et. al. (2023:14-15) report that radiocarbon dates of charcoal and organic material from the upper contact of the Umayyad archaeological deposit (Unit C) range from 605 to 779 CE2 which is in agreement with the phasing of Ad et al (2018) and compatible with destruction layers that were deposited in 749 CE.

Cores C1 and C2 were sampled and analyzed for grain size distribution, foraminiferal assemblage, total organic carbon (TOC), and Inorganic Carbon (IC). An additional 13 surface surface samples, including from storm surge deposits, were also collected, analyzed, and compared with the analysis of the Cores and Southern Baulk in order to help distinguish if a tsunami deposit was indicated in the cores and baulk. Portable-Optically Stimulated Luminescence (P-OSL) dating was also performed on the cores. Four sedimentary units (A-D) were identified in the two cores are were described as follows :

Unit Alias Description Interpretation
A ‘anomalous’ deposit clean, loose quartz sand with no sedimentary structures or cultural artifacts. tsunami deposit
B same sediment as Unit A but with additions of several marine-encrusted potsherds and reddened, partially heat-fused sand clusters. earthquake and fire debris mixed with a tsunami deposit
C 'Umayyad archaeological fill' a dark gray/brown (10YR 6/2), organic-rich layer with many cultural artifacts, including potsherds, glass shards, shells, beach pebbles, charcoal, and bone fragments. Post abandonment deposition from the latter half of the Umayyad period - typical of an ancient garbage dump
D compact earthen floor Umayyad or earlier floor
Everhardt et. al. (2023) interpreted ‘anomalous’ deposit Unit A as tsunamogenic primarily based on grain size distribution and an abundance of foraminifera along with other indicators. As for Unit B, they noted that the reddened, partially heat-fused sand clusters were in agreement with the presence of reddened in-situ building blocks along the intact eastern wall of the room (and elsewhere along the walls) which indicated that a fire took place before the tsunami struck. They also noted an abundance of charcoal found in the upper Umayyad archaeological fill. They viewed the presence of marine-encrusted potsherds as an indicator that these inclusions were previously submerged in the marine system long enough for the encrustation to take place, suggesting that they were transported from the sea to land at the time of the event which in turn could indicate that the tsunami water and deposits extinguished the fire.

Everhardt et. al. (2023) proposed that the lower southern baulk was also a tsunamogenic deposit related to 'anomalous" deposit Unit A in the cores.

Beverly Goodman-Tchernov (personal communication, 2023) suggests that the earthquake did not leave a directional signature of damage and collapse largely because site LL experienced liquefaction during this earthquake but the impact of the tsunami did leave a directional signature as shown in Fig. 8 (Everhardt)
Footnotes

1 Everhardt et. al. (2023:5) reports that fire-reddened walls (see inset of Figure 2C) were found at the same level as the destruction layer(s).

2 Everhardt et. al. (2023:14-15) described the radiocarbon samples as follows:

A single piece of charcoal from the surface of the Umayyad archaeological fill (Unit C) in core C1 has been radiocarbon dated with 95.4% probability to 649–687 cal CE (73.5%) or 743–773 cal CE (22.0%), consistent with the archaeological finds. A second radiocarbon age was measured on a mix of small organic materials from the same layer as the previous charcoal sample, with a result of 605–665 cal CE (95.4% probability).

Tsunami deposit ? Terraced Gardens



Description

  • In addition, there appears to be evidence of landward tsunami deposits. After the Muslim conquest in the 7th century, Caesarea depopulated. In the late 7th or early 8th century CE, the coastal strip south of where the Crusaders would later build their fortifications was transformed into lush terraced gardens irrigated by wells and cisterns ( Dey et al, 2014). Marine layers found on top of these gardens included Glycymeris, a non-edible deeper water bivalve. Atop the marine layer was, in some areas, a burial ground with a funerary inscription providing a terminus ante quem of 870 CE. A terminus post quem of c. 500 came from a reflecting pool fronting the Temple platform and overlain by the marine layer. Dey et al (2014) suggest that the most likely explanation for the transformation from gardens to burial ground was an intervening episode of tsunamogenic destruction. They discussed the potential landward tsunamogenic deposit as follows:
    The most substantial strata attributable to a marine inundation of mid-8th-c. date appeared in the SW sector, along the coastal strip south of the Crusader fortifications. Extensive tracts of these deposits between the temple platform and the theater, a shore-parallel distance of nearly 800 m, were uncovered (and removed, usually mechanically) in the 1970s and early 1980s under the auspices of the Joint Expedition (JECM). The bulk of the deposits lay in a shallow depression situated c.10 m above mean sea-level (MSL) and separated from the sea by a low ridge 15 m above MSL. From the landward side of the ridge, beginning c.50 m from the shore, these marine layers stretched inland as far as 300 m from the sea. 14 They comprised two distinct, superimposed sequences, each consisting of a thick, lower layer of densely-bedded (and in some cases imbricated) shells, rubble and sherds up to 1.5 m thick, topped by a dark, silty layer 20-40 cm thick. Datable materials in the second, upper sequence placed its formation around the 14th c. 15 In the lower sequence, dated by the excavators approximately to the 8th c. on the basis of finds, numerous disarticulated human remains turned up, as well as at least one complete skeleton in Area C, interbedded with the surrounding strata of shells and silt. 16 Like the rest of the materials, this corpse was probably deposited by a (cataclysmic) natural event. As D. Neev and K. Emery indicated in their report, there were no signs of a man-made grave, and the surrounding horizontal strata were uninterrupted above and below the skeleton; such 'culturally non-appropriate burials' are now recognized as a typical feature of tsunami deposits.17 The most likely scenario would have corpses deposited by the retreating waters of the tsunami and immediately covered with more detritus, keeping the articulated skeleton undisturbed by scavenging animals or human intervention.

  • Excavations carried out on the coast of Caesarea yielded deposits which were associated with 6th and 8th century CE tsunami events (Figure 14) - Galili et al (2021:16-17,20)

Collapse and debris Area TPS, on the S side of the Temple Platform and the octagonal church on the platform

Description

  • At Caesarea, the best evidence of destruction attributable to the 749 earthquake comes from Area TPS, on the S side of the Temple Platform, where a thick layer of debris marks the end of the Umayyad occupation of the Late Byzantine bath complex, which was subsequently mulled and built over in the later 8th century - see Raban and Yankelevitz (2008:81) and Arnon (2008:85). Another probable effect of the earthquake was the collapse of the octagonal church on the platform - see Holum et al (2008:30-31). - Dey et al (2014)

Textual Intensity Estimates
Eusebius Mystery Quake - 126-130 CE

Effect Location Image(s) Description Intensity
  • Collapsed Walls                 
Caesarea
  • "Nicopolis and Caesarea were ruined in an earthquake" - Eusebius

  • "An 438 - In that year there was an earthquake: Nicopolis and Caesarea were overthrown. From the Chronological Canon of Andronicus." - Elias of Nisibis
  • VIII+
This evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224).

363 CE Cyril Quake

Effect Location Image(s) Description Intensity
  • Houses Destroyed           
  • Collapsed Walls
Caesarea
  • VIII?
  • VIII?
Although this archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224), much of Caesarea appears to be subject to liquefaction so Intensity is downgraded to VII (7).

749 CE Sabbatical Year Earthquake - Holy Desert Quake

Effect Location Image(s) Description Intensity
  • Places Devastated (Collapsed Walls)
  • Fatalities (likely caused by collapsed walls)
Coastal Palestine
  • Agapius of Manbij, while referring to the Holy Desert Quake of the Sabbatical Year sequence. wrote that "there was a violent earthquake on the coast of the sea of Palestine" and "many places were devastated and many people perished."
  • VIII+
  • VIII+
Although this archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224), the geographic specification of "on the coast of the sea of Palestine" suggests liquefaction may have been at play and Intensity is downgraded to VII (7).

Archaeoseismic and Tsunamigenic Intensity Estimates
Caesarea Harbor Earthquake and/or Tsunami - Late 1st - 2nd century CE

Effect Location Image(s) Description Intensity
Liquefaction and Subsidence outer harbor breakwater



Description

  • The first to second century A.D. basal rubble unit (L4) was found on the carbonate cemented sandstone bedrock (locally known as kurkar) and was characteristic of a high-energy water deposit (Fig. 2). The rubble was framework supported with little surrounding matrix and composed mainly of cobble-sized material, which was well rounded, heavily encrusted (e.g., bryozoans, calcareous algae), and bored (Lithophaga lithophaga, Cliona) on its upper surface. The rubble had variable lithologies including basalts, gabbros, and dolomites, all of which are absent on the Israeli coastal plain and were likely transported to the site as ship ballast (probably from Cyprus). The surrounding matrix was composed of shell material (mainly Glycymeris insubricus), pebbles, and coarse sand. The pottery sherds found in this unit were well rounded, encrusted, and dated to the first to second century A.D. The date for this unit and its sedimentological characters clearly records the existence of high-energy conditions within the inner harbor about 100-200 yr after the harbor was built. This evidence of high-energy water conditions indicates that the outer harbor breakwaters must have been severely degraded by this time to allow waves to penetrate the inner confines of the harbor (Fig. 3, A and B).

    Indication of the rapid destruction of the outer harbor breakwaters toward the end of the first century A.D. is derived from additional data recovered from the outer harbor. In the 1993 season, a late first century A.D. shipwreck was found on the southern submerged breakwater. The merchant ship was carrying lead ingots that were narrowly dated to A.D. 83-96 based on the inscription "IMP.DOMIT.CAESARIS.AUG.GER." which refers to the Roman Emperor Domitianus (Raban, 1999). The wreck was positioned on the harbor breakwater, indicating that this portion of the structure must have been submerged to allow a ship to run-up and founder on top (Raban, 1999; Fig. 3B). Because Josephus praised the harbor in grand terms and referred to it as a functioning entity around A.D. 75-79, and yet portions of the breakwater were submerged by A.D. 83-96, we conclude that there was a rapid deterioration and submergence of the harbor, probably through seismic activity.
    - Reinhardt and Raban (1999)

  • The submergence of the outer harbor break-waters at the end of the first century A.D. could have also been due to seismic liquefaction of the sediment. Excavations have shown that the harbor breakwaters were constructed on well-sorted sand that could have undergone liquefaction with seismic activity. In many instances the caissons are tilted (15°-20° from horizontal; Raban et al., 1999a) and at different elevations, which could be due to differential settling (area K; Fig. 1). However, the tilting could also be due to undercutting by current scour from large-scale storms (or tsunamis) and not exclusively seismic activity. Our data from the inner harbor cannot definitively ascribe the destruction of the harbor at the end of the first century A.D. to a seismic event, although some of the data support this conclusion. However, regardless of the exact mechanism, our sedimentological evidence from the inner harbor and the remains of the late first century A.D. shipwreck indicate that the submergence of the outer breakwater occurred early in the life of the harbor and was more rapid and extensive than previously thought. - Reinhardt and Raban (1999)

VI-VII+
Tsunami Offshore Caesarea


Description

  • Although Goodman-Tchernov and Austin (2015) and earlier researchers associated a 1st - 2nd century CE tsunamite deposit from offshore Caesarea with the Trajan quake of ~115 CE, this association is unlikely. Salamon et al (2011) noted that the presence of a tsunami far south of the supposed epicenter of the Trajan Quake does not fit the usual pattern of tsunamis on the Israeli coast where most tsunamis which hit the coast were generated by ruptures more or less opposite to the coast (e.g. from the Cypriot and Hellenic Arcs). While Salamon et al (2011) suggested a storm surge as a possibility, the work of Goodman-Tchernov and Austin (2015) and earlier publications appears to preclude this as they used a host of indicators to seperate storm surge deposits from tsunamite deposits. I propose that an offshore shelf collapse potentially due to the Incense Road Earthquake of the early 2nd century CE as a likely cause.

  • Goodman-Tchernov and Austin (2015) examined and dated cores taken seaward of the harbor and identified 2 tsunamite deposits (see Tsunamogenic Evidence) including one which dates to to the 1st-2nd century CE. Although, it is tempting to correlate the 1st-2nd century CE tsunamite deposits of Goodman-Tchernov and Austin (2015) to the L4 destruction phase identified in the harbor ( Reinhardt and Raban, 1999), the chronologies presented by Goodman-Tchernov and Austin (2015) suffer from some imprecision due to the usual paucity of dating material that one encounters with cores. Further, the harbor subsidence and breakwater degradation dated by Reinhardt and Raban (1999) may not have been caused by seismic activity. If it was related to seismic activity, the early 2nd century CE Incense Road Quake is a better candidate than the 115 CE Trajan Quake because it would have produced higher intensities in Caesarea.

  • 4.5.2. Sedimentological Findings at Sea Presented as Indicators of a Tsunami

    The core issue in tsunami sedimentology is to distinguish tsunami deposits from beach or storm deposits. Marine fauna and marine deposits found in low-lying, lagoonal water bodies near the coast are often used as paleo tsunami indicators, and so is the presence of large boulders on a rocky coast, away from the sea [42,83,84]. Identifying offshore tsunami deposits is more challenging. It has been less practiced, as there are very few analogies for comparison and it is hard to distinguish them from storm deposits [10,42,83]. A comprehensive study conducted by Mariner et al. [84] analyzed hundreds of published records of tsunami events in the Mediterranean and proposed that 90% of them are problematic and need to be re-examined.

    4.5.3. Outside the Harbor

    At a water depth of 10–12 m offshore, Reinhardt et al. (area W, [42]) identified beds of small angular shell fragments and potsherds dated from the 1st century BCE to the 1st century CE that were overlain by a layer of convex-up-oriented disarticulated bivalve shells. Relying on the fragmentation patterns and stratigraphy of the shells, the authors assumed that these shells could be related to the 115 CE tsunami deposits. Reinhardt et al. [42] also reported on the presence of articulated Glycymeris shells in the tsunami deposit, and suggested that these shells indicate transport from the deeper shelf, as the shallowest habitation depth for these bivalves is 18 m. However, no evidence for the presence of such articulated Glycymeris shells in the discussed deposits have ever been presented or published. Furthermore, Meinis et al. [85] noted that Glycymeris sp. (especially G. insubrica or violescens) were very common along the Israeli coast over long periods. They existed at different depths in a coastal environment (e.g., 8–16 m depth) and even at 200 m water depth. In the Adriatic Sea, their habitat was reported to be at a water depth of 2–40 m [86]. Moreover, Reinhardt et al. [42] give no explanation of how these articulated mollusks survived what they describe as the “ . . . intense wave turbulence, shell-to-shell impacts, and shells striking the harbor moles or bedrock under high wave energy, as generated by a tsunami”. Given the above, there is nothing special in finding G. insubrica in sea bed sediments which are shallower than 18 m. The existence of articulated Glycymeris bivalves in the discased Caesarea deposits is yet to be proven, while the preservation of such articulated shells under a catastrophic tsunami that was assumed to destroy the Roman Harbor, is still to be explained.

    As noted above, it is difficult to distinguish between tsunami and storm deposits [83,84,87,88]. Sakuna et al. [89] noted the difficulty in identifying the shallow-marine tsunami deposits associated with the 2004 Indian Ocean tsunami based on sedimentological evidence. Tamura et al. [10], who study the 2011 tsunami in Japan, concluded that this tsunami (“one of the largest modern tsunamis in the last 1200 years”) did not produce distinct sedimentary records in Sendai Bay. He also stated that there are no established unequivocal criteria for identifying shallow marine tsunami deposits and that it is impossible to identify the associated deposits at sea, since they are not preserved and might have been mixed by storms [10]. Their results agree with the suggestions of Weiss and Bahlburg [90] that the offshore tsunami deposits are unlikely to be preserved at depths shallower than 65 m. In this regard, the deposits identified by Reinhardt et al. [42] as the result of the 115 tsunami that is supposed to have destroyed the harbor, are questionable, as are the three reflected sub-bottom layers identified by Goodman-Tchernov and Austin [9] as tsunami features.
    - Galili et al (2021:16-17,20)

IX +
Tsunami Harbor



Description

  • The first to second century A.D. basal rubble unit (L4) was found on the carbonate cemented sandstone bedrock (locally known as kurkar) and was characteristic of a high-energy water deposit (Fig. 2). The rubble was framework supported with little surrounding matrix and composed mainly of cobble-sized material, which was well rounded, heavily encrusted (e.g., bryozoans, calcareous algae), and bored (Lithophaga lithophaga, Cliona) on its upper surface. The rubble had variable lithologies including basalts, gabbros, and dolomites, all of which are absent on the Israeli coastal plain and were likely transported to the site as ship ballast (probably from Cyprus). The surrounding matrix was composed of shell material (mainly Glycymeris insubricus), pebbles, and coarse sand. The pottery sherds found in this unit were well rounded, encrusted, and dated to the first to second century A.D. The date for this unit and its sedimentological characters clearly records the existence of high-energy conditions within the inner harbor about 100-200 yr after the harbor was built. This evidence of high-energy water conditions indicates that the outer harbor breakwaters must have been severely degraded by this time to allow waves to penetrate the inner confines of the harbor (Fig. 3, A and B).

    Indication of the rapid destruction of the outer harbor breakwaters toward the end of the first century A.D. is derived from additional data recovered from the outer harbor. In the 1993 season, a late first century A.D. shipwreck was found on the southern submerged breakwater. The merchant ship was carrying lead ingots that were narrowly dated to A.D. 83-96 based on the inscription "IMP.DOMIT.CAESARIS.AUG.GER." which refers to the Roman Emperor Domitianus (Raban, 1999). The wreck was positioned on the harbor breakwater, indicating that this portion of the structure must have been submerged to allow a ship to run-up and founder on top (Raban, 1999; Fig. 3B). Because Josephus praised the harbor in grand terms and referred to it as a functioning entity around A.D. 75-79, and yet portions of the breakwater were submerged by A.D. 83-96, we conclude that there was a rapid deterioration and submergence of the harbor, probably through seismic activity.
    - Reinhardt and Raban (1999)

  • The submergence of the outer harbor break-waters at the end of the first century A.D. could have also been due to seismic liquefaction of the sediment. Excavations have shown that the harbor breakwaters were constructed on well-sorted sand that could have undergone liquefaction with seismic activity. In many instances the caissons are tilted (15°-20° from horizontal; Raban et al., 1999a) and at different elevations, which could be due to differential settling (area K; Fig. 1). However, the tilting could also be due to undercutting by current scour from large-scale storms (or tsunamis) and not exclusively seismic activity. Our data from the inner harbor cannot definitively ascribe the destruction of the harbor at the end of the first century A.D. to a seismic event, although some of the data support this conclusion. However, regardless of the exact mechanism, our sedimentological evidence from the inner harbor and the remains of the late first century A.D. shipwreck indicate that the submergence of the outer breakwater occurred early in the life of the harbor and was more rapid and extensive than previously thought. - Reinhardt and Raban (1999)

  • 4.5.4. Tsunami Deposits in the Eastern (Inner) Basin

    Excavations in the eastern basin [40] yielded a thin layer of sediments from the 1st to 2nd centuries CE, overlain by a deposit of mixed sediments. They determined that in the 1st century, and evidently up to the 3rd century CE, the prevailing conditions in the eastern basin were of a brackish body of water with good circulation. Thus, the inner harbor seems to have been in use after 115 CE. The mixed sediment deposits discovered in the eastern basin was attributed by Reinhardt and Raban [40] to cleaning and deepening of the harbor in early periods. The proposed main mechanisms for the destruction of the harbor in the study by Reinhardt and Raban [40] were the seismic and tectonic scenarios. Later, however, after reassessing the finds in light of the available new studies on tsunamis, the tectonic and seismic scenarios, as well as the dredging deposit hypothesis, gave way to the 115 CE tsunami scenario [42].

    - Galili et al (2021:16-17,20)

IX +
Fallen port architecture harbor


Description

  • At the very deepest spot where the airlift penetrated, beneath huge stone blocks which teetered precariously above the divers' heads, was uncovered a large wooden beam. Beneath its protective cover the divers found the only whole amphora of our dig. This proved to be a second century Roman vessel. The fact that it was found under the tumbled beam and masonry would indicate that these things were catapulted into the sea at the same time. Since there is a strong earthquake recorded in the area of Caesarea in the year A.D. 130 [JW: this refers to the Eusebius Mystery Quake - could also be Incense Road Quake], it may possibly be that the harbor installations of Herod were destroyed at that time. - Fritsch and Ben-Dor (1961)

VIII +
Although the archeoseismic evidence requires a minimum Intensity of IX (9) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224), such an Intensity would have leveled Caesarea and there is no accompanying evidence of damage to structures and massive rebuilding. An Intensity of IX (9) appears to be an over estimate and highlights the probability that tsunamogenic evidence in Caesarea was likely derived from either far field tsunamis or localized offshore shelf collapse. Potential Intensity is downgraded to VI (6), VII (7), or VIII (8).

Coin Hoard Quake - 4th century CE

Effect Location Image(s) Description Intensity
  • Collapse?                  
  • Coin Hoard
Synagogue in Field O


  • Raphael and Bijovsky (2014) examined what they describe as "a large hoard of 3,700 copper coins" discovered during excavations of a building that the original excavator, Avi-Yonah, identified as a synagogue. They report that the latest coins in the hoard date to 361 CE, leading them to conclude that the building was destroyed by the 363 CE earthquake and not during the Gallus Revolt (~352 CE).
  • VIII+?
  • ?
Although this archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224), the location of the Stratum IV synagogue close to the seashore suggests liquefaction may have been at play and Intensity is downgraded to VII (7).

Vault 2 in Area CV Quake - mid-7th century CE

Effect Location Image(s) Description Intensity
  • Vault Collapse     
  • Crushed Pottery (Wall Collapse)
Vault 2 in Area CV



  • From the evidence that was found upon pavement 1047 and on the clay and plaster layers of CV/2, it is clear that Vault 2 and this structure immediately in front of it remained in use up to the point of collapse. The structure appears to have been destroyed suddenly, because collapsed vault and other structural elements crushed pottery vessels that were resting on the floors (figs. 132, 133). No fire was associated with this destruction.

    Vault 2 appears to have collapsed downward, while the frontal arcade structure appears to have fallen both to the west and downward. From the collapsed superstructure of the arcade one can determine that the second storey had a white tesselated floor, probably with a black border, since many fragments of this floor were found in the destruction, including one segment over 3 m. long and at least a meter wide where it emerged from the balk. This segment was upside down, having apparently turned over during the collapse. Above this floor segment many broken roof tiles were found. Thus it appears that the structure was of two storeys and roofed.
    - Raban et al. (1993 v. I:64)
  • VIII+
  • VIII+
Although this archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224), the location of Area CV close to the seashore suggests liquefaction may have been at play and Intensity is downgraded to VII (7). Jeffrey Blakely in Raban et al. (1993 v. I:64) described Vault 2 as a two-story structure that collapsed downward, with its arcade collapsing toward the west.

mid-8th century CE Earthquake

Effect Location Image(s) Description Intensity
Tsunami                   Offshore Caesarea and Jisr al-Zikra



Description

  • Goodman-Tchernov et al (2009) identified tsunamites in cores taken immediately offshore of the harbor of Caesarea which Goodman-Tchenov and Austin (2015) dated to the 5th - 8th century CE and associated with tsunamis generated by the Beirut Quake of 551 CE and one of the Sabbatical Year Quakes. Although earlier works assigned this 5th - 8th century tsunamite deposit solely to the Beirut Quake of 551 CE, later revisions assigned this offshore deposit mostly to one of the Sabbatical Year Quakes with the suggestion that the Sabbatical Year Quake tsunami deposit contained some reworked tsunamites from the Beirut Quake of 551 CE. The revision may be based on the analysis of re-interpreted landward tsunami deposits (see Fig. 14 above from Galili et. al., 2021) which were dated by Dey et al (2014) to around the time of the Sabbatical Year Quakes. The chronology of the cores was determined using an assemblage of ceramic finds, radiocarbon, and optically stimulated luminescence (OSL) dating. Multiple indicators were used to distinguish tsunami deposits from storm deposits. Particle size distributions were shown to be particularly helpful and reliable. Tsunami horizons were characterized by a wider range of grain sizes and poorer sorting.

    Although efforts to distinguish two tsunami events in the 5th-8th century tsunamogenic deposit by coring in deeper water where an intervening layer, for example, might be present are reported in publications such as Dey et al (2014), this has not yet, to my knowledge, been accomplished. Tsunamogenic evidence for for an event in the mid 8th century CE (e.g. the Holy Desert Quake of the Sabbatical Year Quakes) is better supported than for the 551 CE Beirut Quake although it is possible that both earthquakes generated a tsunami which struck Caesarea.

  • Tyuleneva et. al. (2017) identified what appears to be the same tsunamite in a core (Jisr al-Zarka 6) taken offshore of nearby Jisr al-Zakra. This core was located ~1.5-4.5 km. north of the Caesarea cores. The tsunamite deposit from Jisr al-Zarka was more tightly dated to 658-781 CE (1292-1169 Cal BP) – within the time window for the Holy Desert Quake of the Sabbatical Year Earthquake sequence.

IX +
Tsunami Harbor



Description

  • Goodman-Tchernov and Austin (2015) produced a description of a potential tsunami deposit in the shallow intermediate harbor.
    In excavations of the shallow intermediate harbor (TN area, Fig. 1C; Reinhardt and Raban, 2008:155-182 ), there is an extensive deposit of mixed (Early Islamic- Byzantine–4th to 8th century CE) refuse, ranging from high-value intricate items of varying erosion state and exposure—suggesting broad mixing of typical harbor refuse (e.g., broken amphora/pots) and newly introduced, undamaged domestic wares and personal items (e.g., intricate hair combs, fine sections of Islamic coins, statuette, a satchel of copper coins). Unlike other harbor deposits, these materials are of broad origin (domestic, commercial, religious), value range and preservation state, suggesting the kind of non-deliberate and rapid burial a tsunami event would produce. In addition, because the ages of the ceramics found in this excavation range from early Islamic to late Byzantine (6th through 8th centuries CE), no distinctive stratigraphy offshore today separates what may have been two distinct tsunami events.
    Dey and Goodman-Tchernov (2010:278) reported on potential 6th century CE tsunami deposits in the inner and outer harbors.
    The inner harbour was blanketed with a thick deposit of heterogeneous rubble, including bones and other organic remains, pottery, and architectural materials.63 Meanwhile, in the outer harbour, a powerful scouring effect mixed materials datable from the 1st c. B.C. to the 6th c. A.D. into a single, undifferentiated mass, further undermined the breakwaters, and cut a trench into the channel between the outer moles.64 The signs from both the inner and outer harbour are dramatic enough to have led previous commentators already to propose the tsunami of 551 as a possible cause.65

    Footnotes

    [63] Raban 1996, 662; Yule and Barham 1999, 277-78; Reinhardt and Raban 2008, 177-78.

    [64] Reinhardt and Raban 2008, 178-79.

    [65] See, e.g., Raban 1996, 662; Yule and Barham 1999, 277-78; Reinhardt and Raban 2008, 177-78.

IX +
Collapsed Vault or Walls, Tsunami, and a Fire Area LL


Fig. 8 (Ad)

Fig. 3

Fig. 2B

Fig. 2C

Fig. 4

Fig. 5

Fig. 8 (Everhardt)
Description

Site LL is located just north of Caesarea's inner harbour. Ad et al (2018) excavated the site which was in use from the Herodian period to the Umayyad period. A storage structure (aka "the warehouse") was identified in the western part of the site which appears to have been constructed in Herodian times and remained in use, as it underwent changes, until the middle of the Umayyad period (~700 CE). After the Islamic conquest of Caesarea (640 CE), rooms were partitioned, floors were raised, construction was added and some of the openings were sealed. Ceramics indicate that the site was abandoned at the end of the 7th century CE after which it suffered two major destruction events before re-occupation occurred in the mid 8th century CE in what was interpreted as Abbasid Strata V (the Abbasid Caliphate began ruling in 750 CE). During the renewed Abbasid occupation, destruction debris were preserved as the builders preferred to level the area and build above the destruction layer(s). The destruction events within Stratum VI (Umayyad) appear to be an earthquake and a tsunami; both likely a result of the the Holy Desert Quake of the Sabbatical Year Quake sequence.

Ad et al (2018) report that during the earthquake event several ceilings collapsed inward, and there was evidence of a fire in the eastern warehouse.1 In the collapse in the corridor, the original order of the courses of the wall or vault could be clearly identified (Fig. 8) adding confidence to a seismic interpretation. During the subsequent tsunami event, a layer of sand and collapsed building stones had accumulated to a height of more than 2 m in Rooms 8–11 in the western warehouse and to a height of 1.5 m in Rooms 12–14 and the corridor of the eastern warehouse. Everhardt et. al. (2023) further examined the destruction deposits by taking cores and radiocarbon samples as well as examining burn evidence and a baulk inside the collapsed corridor.

The cores (C1 and C2) were taken in the collapsed corridor after the Abbasid floor was removed, thus sampling the destruction deposits. See Fig. 1E for location of the cores (and southern baulk) and Fig. 3 for photos and descriptions of the cores and the southern baulk. A ~20 mg. charcoal sample from the top 3 cm of sediment in the Umayyad archaeological fill and one untreated sample of various organic material (~20 mg) from the top 5 cm of the same layer in core C1, as close as possible to the contact with the lower anomalous deposit, were collected for radiocarbon dating. Everhardt et. al. (2023:14-15) report that radiocarbon dates of charcoal and organic material from the upper contact of the Umayyad archaeological deposit (Unit C) range from 605 to 779 CE2 which is in agreement with the phasing of Ad et al (2018) and compatible with destruction layers that were deposited in 749 CE.

Cores C1 and C2 were sampled and analyzed for grain size distribution, foraminiferal assemblage, total organic carbon (TOC), and Inorganic Carbon (IC). An additional 13 surface surface samples, including from storm surge deposits, were also collected, analyzed, and compared with the analysis of the Cores and Southern Baulk in order to help distinguish if a tsunami deposit was indicated in the cores and baulk. Portable-Optically Stimulated Luminescence (P-OSL) dating was also performed on the cores. Four sedimentary units (A-D) were identified in the two cores are were described as follows :

Unit Alias Description Interpretation
A ‘anomalous’ deposit clean, loose quartz sand with no sedimentary structures or cultural artifacts. tsunami deposit
B same sediment as Unit A but with additions of several marine-encrusted potsherds and reddened, partially heat-fused sand clusters. earthquake and fire debris mixed with a tsunami deposit
C 'Umayyad archaeological fill' a dark gray/brown (10YR 6/2), organic-rich layer with many cultural artifacts, including potsherds, glass shards, shells, beach pebbles, charcoal, and bone fragments. Post abandonment deposition from the latter half of the Umayyad period - typical of an ancient garbage dump
D compact earthen floor Umayyad or earlier floor
Everhardt et. al. (2023) interpreted ‘anomalous’ deposit Unit A as tsunamogenic primarily based on grain size distribution and an abundance of foraminifera along with other indicators. As for Unit B, they noted that the reddened, partially heat-fused sand clusters were in agreement with the presence of reddened in-situ building blocks along the intact eastern wall of the room (and elsewhere along the walls) which indicated that a fire took place before the tsunami struck. They also noted an abundance of charcoal found in the upper Umayyad archaeological fill. They viewed the presence of marine-encrusted potsherds as an indicator that these inclusions were previously submerged in the marine system long enough for the encrustation to take place, suggesting that they were transported from the sea to land at the time of the event which in turn could indicate that the tsunami water and deposits extinguished the fire.

Everhardt et. al. (2023) proposed that the lower southern baulk was also a tsunamogenic deposit related to 'anomalous" deposit Unit A in the cores.

Beverly Goodman-Tchernov (personal communication, 2023) suggests that the earthquake did not leave a directional signature of damage and collapse largely because site LL experienced liquefaction during this earthquake but the impact of the tsunami did leave a directional signature as shown in Fig. 8 (Everhardt)
Footnotes

1 Everhardt et. al. (2023:5) reports that fire-reddened walls (see inset of Figure 2C) were found at the same level as the destruction layer(s).

2 Everhardt et. al. (2023:14-15) described the radiocarbon samples as follows:

A single piece of charcoal from the surface of the Umayyad archaeological fill (Unit C) in core C1 has been radiocarbon dated with 95.4% probability to 649–687 cal CE (73.5%) or 743–773 cal CE (22.0%), consistent with the archaeological finds. A second radiocarbon age was measured on a mix of small organic materials from the same layer as the previous charcoal sample, with a result of 605–665 cal CE (95.4% probability).

VIII-IX +
Tsunami deposit ? Terraced Gardens



Description

  • In addition, there appears to be evidence of landward tsunami deposits. After the Muslim conquest in the 7th century, Caesarea depopulated. In the late 7th or early 8th century CE, the coastal strip south of where the Crusaders would later build their fortifications was transformed into lush terraced gardens irrigated by wells and cisterns ( Dey et al, 2014). Marine layers found on top of these gardens included Glycymeris, a non-edible deeper water bivalve. Atop the marine layer was, in some areas, a burial ground with a funerary inscription providing a terminus ante quem of 870 CE. A terminus post quem of c. 500 came from a reflecting pool fronting the Temple platform and overlain by the marine layer. Dey et al (2014) suggest that the most likely explanation for the transformation from gardens to burial ground was an intervening episode of tsunamogenic destruction. They discussed the potential landward tsunamogenic deposit as follows:
    The most substantial strata attributable to a marine inundation of mid-8th-c. date appeared in the SW sector, along the coastal strip south of the Crusader fortifications. Extensive tracts of these deposits between the temple platform and the theater, a shore-parallel distance of nearly 800 m, were uncovered (and removed, usually mechanically) in the 1970s and early 1980s under the auspices of the Joint Expedition (JECM). The bulk of the deposits lay in a shallow depression situated c.10 m above mean sea-level (MSL) and separated from the sea by a low ridge 15 m above MSL. From the landward side of the ridge, beginning c.50 m from the shore, these marine layers stretched inland as far as 300 m from the sea. 14 They comprised two distinct, superimposed sequences, each consisting of a thick, lower layer of densely-bedded (and in some cases imbricated) shells, rubble and sherds up to 1.5 m thick, topped by a dark, silty layer 20-40 cm thick. Datable materials in the second, upper sequence placed its formation around the 14th c. 15 In the lower sequence, dated by the excavators approximately to the 8th c. on the basis of finds, numerous disarticulated human remains turned up, as well as at least one complete skeleton in Area C, interbedded with the surrounding strata of shells and silt. 16 Like the rest of the materials, this corpse was probably deposited by a (cataclysmic) natural event. As D. Neev and K. Emery indicated in their report, there were no signs of a man-made grave, and the surrounding horizontal strata were uninterrupted above and below the skeleton; such 'culturally non-appropriate burials' are now recognized as a typical feature of tsunami deposits.17 The most likely scenario would have corpses deposited by the retreating waters of the tsunami and immediately covered with more detritus, keeping the articulated skeleton undisturbed by scavenging animals or human intervention.

  • Excavations carried out on the coast of Caesarea yielded deposits which were associated with 6th and 8th century CE tsunami events (Figure 14) - Galili et al (2021:16-17,20)

IX +
Collapse and debris Area TPS, on the S side of the Temple Platform and the octagonal church on the platform

Description

  • At Caesarea, the best evidence of destruction attributable to the 749 earthquake comes from Area TPS, on the S side of the Temple Platform, where a thick layer of debris marks the end of the Umayyad occupation of the Late Byzantine bath complex, which was subsequently mulled and built over in the later 8th century - see Raban and Yankelevitz (2008:81) and Arnon (2008:85). Another probable effect of the earthquake was the collapse of the octagonal church on the platform - see Holum et al (2008:30-31). - Dey et al (2014)

VIII +
Although the archeoseismic evidence requires a minimum Intensity of IX (9) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224), such an Intensity would have leveled Caesarea and there is no accompanying evidence of widespread leveling of structures. An Intensity of IX (9) is a gross over estimate and highlights the probability that tsunamogenic evidence in Caesarea was likely derived from localized offshore shelf collapse. In addition, the possibility of liquefaction at Caesarea suggests that bedrock intensity could have been as low as VII (7) to create the seismic effects observed.

Plots
Salamon and Di Manna Plot

  • Bounding Envelopes for landslide tsunamis from Salamon and Di Manna (2019)
     



Calculators
Incense Road Earthquake

Variable Input Units Notes
Magnitude
km. Distance to earthquake producing fault
Variable Output - Site Effect not considered Units Notes
unitless Local Intensity
unitless Conversion from Intensity to PGA using Wald et al (1999)
  

Distances to Caesarea

Incense Road Earthquake
Location Approx. Distance
to Caesarea (km.)
en Feshka
(N end of Dead Sea)
105
al-Masraa, Jordan
(S end of Dead Sea)
136
Safi, Jordan 173
Taybeh Trench 235
Qatar Trench 290

Trajan Quake

Variable Input Units Notes
Magnitude
km. Distance to earthquake producing fault
Variable Output - Site Effect not considered Units Notes
unitless Local Intensity
unitless Conversion from Intensity to PGA using Wald et al (1999)
  

Distances to Caesarea

Trajan Quake
Location Approx. Distance
to Caesarea (km.)
al-Harif Aqueduct 320
Apamea 350
Antioch 430

551 CE Beirut Quake

Variable Input Units Notes
Magnitude
km. Distance to earthquake producing fault
Variable Output - Site Effect not considered Units Notes
unitless Local Intensity
unitless Conversion from Intensity to PGA using Wald et al (1999)
  

Distances to Caesarea

551 CE Beirut Quake
Location Approx. Distance
to Caesarea (km.)
Tyre 88
Sidon 123
Beirut 163
Estimated Epicenter of Elias et al (2007) 175
Byblos 192

Sabbatical Year Quakes - Holy Desert Quake

Variable Input Units Notes
Magnitude
km. Distance to earthquake producing fault
Variable Output - Site Effect not considered Units Notes
unitless Local Intensity
unitless Conversion from Intensity to PGA using Wald et al (1999)
  

Distances to Caesarea

Holy Desert Quake (749)
Location Approx. Distance
to Caesarea (km.)
Bet She'an 56
Tiberias 68

Notes and Further Reading
References

Articles and Books

‘Ad, U.; Kirzner, D., Shotten-Hallel, Vardit, and Gendelman, P., 2017, the Crusader Market. Preliminary Report; Hadashot Arkheologiyot

‘Ad, U.; Arbel, Y.; Gendelman, P. Caesarea, 2018, Area LL. 2018; Hadashot Arkheologiyot

Arnon, Y. D. 2008. Caesarea Maritima, the late periods (700-1291 CE) (BAR 51771; Oxford).

Betlyon and Killebrew (2016) A Fourth-Century CE Coin Hoard from the Qaṣrin Village , in Viewing Ancient Jewish Art and Archaeology (ed. Ann E. Killebrew and Gabriele Faßbeck)

Boyce et al. (2003) Magnetic Mapping of Buried Hydraulic Concrete Harbour Structures: King Herod’s Harbour, Caesarea Maritima, Israel , Maritime Archaeology Paper 03-01: King Herod’s Harbour Copyright 2003 Marine Magnetics Corp.

Dey, H. and B. Goodman-Tchernov (2010). "Tsunamis and the port of Caesarea Maritima over the longue durée: a geoarchaeological perspective." Journal of Roman Archaeology 23: 265-284.

Dey, H., et al. (2014). "Archaeological evidence for the tsunami of January 18, A.D. 749: a chapter in the history of Early Islamic Qâysariyah (Caesarea Maritima)." Journal of Roman Archaeology 27: 357-373.

Everhardt, C. J., et al. (2023). "Earthquake, Fire, and Water: Destruction Sequence Identified in an 8th Century Early Islamic Harbor Warehouse in Caesarea, Israel." Geosciences 13(4): 108.

Fritsch, C. T. and I. Ben-Dor (1961). "The Link Expedition to Israel, 1960." The Biblical Archaeologist 24(2): 50-59.

Galili, E., et al. (2011). Port and Mooring installations in Caesarea and the destruction of Herodian harbour - Update assessment based on underwater surveys and excavations: 167-192. in Michmanei-Caesarea (Caesarea Treasures), Summaries and Studies on Caesarea and its area. In honor of Dr. Yosef Porath (In Hebrew)Chapter: Publisher: Keter Publishing House, Jerusalem - in Hebrew

Galili, E., et al. (2021). "Archaeological and Natural Indicators of Sea-Level and Coastal Changes: The Case Study of the Caesarea Roman Harbor." Geosciences (Switzerland) 11.

Goodman-Tchernov, B. N., et al. (2009). "Tsunami waves generated by the Santorini eruption reached Eastern Mediterranean shores." Geology 37(10): 943-946.

Goodman-Tchernov, B. N. and J. A. Austin Jr (2015). "Deterioration of Israel's Caesarea Maritima's ancient harbor linked to repeated tsunami events identified in geophysical mapping of offshore stratigraphy ." Journal of Archaeological Science: Reports 3: 444-454.

Holum, K. G., Hohfelder, R. L., Bull, R. J., and Raban, A., 1988, King Herod’s dream: Caesarea on the sea : New York, W.W. Norton, 244 p. - can be borrowed with a free account from archive/org

Irish, J. L., Weiss, R., & Goodman-Tchernov, B. (2020). A Monte-Carlo Model For Caisson Overturning By Tsunamis. Coastal Engineering Proceedings, (36v), currents.1.

Langgut, D., Eli Yannai, Itamar Taxel, Amotz Agnon & Shmuel Marco (2016) Resolving a historical earthquake date at Tel Yavneh (central Israel) using pollen seasonality, Palynology, 40:2, 145-159

Marco, S., Katz, O., Dray, Y., 2014. Historical sand injections on the Mediterranean shore of Israel: evidence for liquefaction hazard. Nat. Hazards 1449–1459.

Mart and Perecman(1996). Caesarea: Unique Evidence for Faulting Patterns and Sea Level Fluctuations in the Late Holocene. Caesarea Maritima: A Retrospective after Two Milennia. Leiden, Brill: 3-24.

Mesqui, Jean and Faucherre, Nicolas (2006) L’enceinte médiévale de Césarée, in: Bulletin Monumental 164-1 (2006), pp. 83-94

Raban, A. (1996). The inner harbor basin of Caesarea: archaeological evidence for its gradual demise

Raban, A. and S. Yankelevitz 2008. "A Byzantine/Early Islamic bath on the S flank of the Temple Plat-form, excavations 1995," in Holum, Stabler and Reinhardt 2008, 67-84.

Raphael and Bijovsky (2014) The Coin Hoard from Caesarea Maritima and the 363 CE Earthquake , Israel Numismatic Research, Volume 9, pp. 173-192, Published by the Israel Numismatic Society

Reinhardt, E. G. and A. Raban (1999). "Destruction of Herod the Great's harbor at Caesarea Maritima, Israel—Geoarchaeological evidence." Geology 27(9): 811-814.

Reinhardt, E.G. (1999) Stratigraphic excavation of the outer harbor deposits: Preliminary report (1994) , in Holum, K.G., et al., eds., Caesarea Papers 2: Journal of Roman Archaeology, Supplementary Series No. 35, p. 189-197.

Reinhardt, E. G., et al. (2006). "The tsunami of 13 December A.D. 115 and the destruction of Herod the Great's harbor at Caesarea Maritima, Israel." Geology 34(12): 1061-1064.

Reinhardt and Raban, 2008, Site formation and stratigraphic development of Caesarea’s ancient harbor in Holum, K. G., et al. (2008). Caesarea Reports and Studies: Excavations 1995-2007 Within the Old City and the Ancient Harbor.

Rink, W. J. (2008) Optical luminescence dating of sediments from Herod’s harbor in Holum, K. G., et al. (2008). Caesarea Reports and Studies: Excavations 1995-2007 Within the Old City and the Ancient Harbor.

Salamon, A., et al. (2011). "A critical evaluation of tsunami records reported for the Levant Coast from the second millennium bce to the present." Isr. J. Earth Sci. 58: 327-354.

Salamon, A. and P. Di Manna (2019). "Empirical constraints on magnitude-distance relationships for seismically-induced submarine tsunamigenic landslides." Earth-Science Reviews 191: 66-92.

Tyuleneva, N., et al. (2017). "A new chalcolithic-era tsunami event identified in the offshore sedimentary record of Jisr al-Zarka (Israel)." Marine Geology 396: 67-78.

Stabler, J, and K. Holum 2008. "The warehouse quarter (area LL) and the Temple Platform (area TP), 1996-2000 and 2002 seasons," in Holum, Stabler and Reinhardt 2008, 1-39.

Steele, R. E., et al. (2024). "Anthropogenic structure emplacement and sediment transport at King Herod's harbour, Israel: ED-μXRF (Itrax) data and foraminifer Pararotalia calcariformata as proxies of coastal development over millennia." Marine Geology 469: 107245.

Toombs (1978). The Stratigraphy of Caesarea Maritima. Archaeology in the Levant: Essays for Kathleen Kenyon. R. M. a. P. Parr. Warminster. England, Aris and Phillips: 233-232.

Whitcomb, D. (2011) “Qaysariya as an Early Islamic Settlement.” In Shaping the Middle East: Jews, Christians, and Muslims in an Age of Transition, 400-800 C.E..(2011).United States:University Press of Maryland.

Whitcomb, D. (2016) “Notes for an archaeology of Muʿāwiya: material culture in the transitional period of believers.” In A. Borrut and F. M. Donner, eds. Christians and Others in the Umayyad State.(2016).United States: Oriental Institute of the University of Chicago.

Comprehensive Bibliography from Caesarea-Maritima.org

Collection of all known works of modern scholarship and popular publications
Collection of Testimonia

Bibliography from Stern et al (1993 v.1)

Main publications

L. Kadman, The Coins ofCaesarea Maritima (Corpus Nummorum Palaestinensium 2), Tel Aviv 1957

King Herod's Dream: Caesarea on the Sea (Exhibition Cat., Smithsonian Institution, eds. K. G. Holum et al.), New York 1988.

Other studies

Conder-Kitchener, SWP 2, 13-29

L. Haefeli, Caesarea am Meer, Miinster 1923; A. Reifenberg, IEJ l (1950-1951), 20-32

H. Hamburger, 'Atiqot l (1955), 115-138

8 (1968), l-38

id., IEJ9 (1959), 43-45

20 (1970), 81-91

S. Yeivin, Archaeology 8 (1955), 122-129

B. Lifshitz, RB70(1963), 556-558

74 (1967), 45-59

id., Scripta Classica Israelica 2 (1975), 108-109, 112

J.D. Brierman, IEJ 19 (1969), 44-45

J. Fitz, Latomus 28 (1969), 126-140

H. Petor, Antike Welt 1 (1970), 47-53

R. Diplock, PEQ 103 (1971), I 1-16

105 (1973), 165-166

T. D. Newman, BA 34 (1971), 88-91

M. W. Prausnitz, IEJ 21 (1971), 227

S. E. Smith, RB 78 (1971), 591-593

E. Weber, Bonner Jahrbuch 171 (1971), 194-200

J. Ringel, Sefunim 4 (1972-1975), 22-27

id., Revue Numismatique 6e Serie 16 (1974), 155-159

id., Cesanie de Palestine: Etude historique et archeologique, Paris 1975

ibid. (Reviews), IEJ26 (1976), 215- 216.- Syria 53 (1976), 349.- PEQ 109 (1977), 62-63

id., Mediterranean Historical Review 3 (1988), 63-73

H. Seyrig, Syria 49 (1972), 112-115

S. Dar and S. Applebaum, PEQ 105 (1973), 91-99; H. Bietenhard, Caesarea, Origenes und die Juden (Franz Delitzsch-Vorlesungen 1972), Stuttgart 1974; H. W. Hazard, Near Eastern Numismatics(G. C. Miles Fest.), Beirut 1974, 359-368

A. Siegelmann, IEJ 24 (1974), 216-221

L. M. Hopfe and G. Lease, BA 38 (1975), 2-10

J. H. Riley, BASOR 218 (1975), 25- 63

M. Christo!, Zeitschriftfur Papyrologie und Epigraphik 22 (1976), 169-176

A. Flinder,/EJ26 (1976), 77-80

id., BAlAS I (1982), 25-27

R. L. Hohlfelder, Byzantine Studies Conference: Abstracts of Papers 3 (1977), 69-70

8 (1982), 18-19

id., City, Town and Countryside, New York 1982, 65-73

id., Ancient Coins of the Graeco-Roman World (eds. W. Heckel and R. Sullivan), Waterloo, Ont. 1984, 261-285

id., National Geographic 171/2 (1987), 260-279

id., Caesarea Maritima, Israel: A National Park and an International Archaeological Monument Under Siege (International Perspectives on Cultural Parks, Proc., I st World Conference, 1984) Washington 1989

A. Kasher, Jewish Quarterly Review 68 (1977), 16- 27

L. Cervellin, Terra Santa (1978), 125

D. E. Groh, Levant 10 (1978), 165-169

W. E. Kaegi, Jr., IEJ28 (1978), 177-181

X. Lorio!, Revue des Etudes Anciennes 80 (1978), 72-80

L. Y. Rahmani, RB 85 (1978), 268-276

88 (1981), 240-244

id., JEJ 38 (1988), 246-248

P. I. Fransen, MdB 12 (1980), 5-13, 21-25; D. W. Roller, BASOR 238 (1980), 35-42

252 (1983), 61-68

id., RB 88 (1981), 582-583

id., Levant 14 (1982), 90-103

V. Sussman, 'Atiqot 14 (1980), 76-79

Buried History 17/2 (1981), 7-16

H.-D. Neef, ZDPV97 (1981), 74-80

M. Spiro, AlA 85 (1981), 219

id., Byzantine Studies Conference: Abstracts of Papers 7 (1981 ), 10-11

R. C. Wiemken and K. G. Holum, BASOR 244 (1981 ), 27-52

K. G. Holum, City, Town and Countryside, New York 1982, 65-74

id., IEJ 36 (1986), 61-64

id., Archaeology 41/3 (1988), 44-47

id., Studia Pompeiana et Classica (W. F. Jashemski Fest.) 2, New Rochelle, N.Y. 1989, 87-104; E. Puech, RB89(!982), 210-221

Z. Rubin, Jerusalem Cathedral (1982), 79-105

R. L. Vann, City, Town and Countryside, New York 1982, 165-198

C. Dauphin, BAlAS 1982-1983, 25-31

H. K. Beebe, JNES 42 (1983), 195-207

A. Betz, Pro Arte Antiquo (H. Kenner Fest.), Vienna 1983, 33-36

C. M. Lehmann, Zeit fur Papyrologie und Epigraphik 51 (1983), 191-195

id., AlA 88 (1984), 250-251

id., Classical Philology 79 (1984), 45-52

C. J. Lenzen, "The Byzantine/Islamic Occupation at Caesarea Maritima as Evidenced through the Pottery" (Ph.D. diss., Drew Univ. 1983

Ann Arbor 1986)

E. Trocme, MdB 27 (1983), 28-30

E. Will, Fondation Eugene Piot (Monuments et Memoires 65) (1983), 1-24

id., Syria 64 (1987), 245-251

R. Gersht, Scripta Classica Israelica 7 (1983-1984), 53-57

id., PEQ 116 (1984), 110- 114

id., TA 13-14 (1986-1987), 67-70

id. IEJ 41 (1991), 145-156

Y. Meshorer, Israel Numismatic Journal8 (1984-1985), 37-58

D. Pringle, Levant 17 (1985), 171-202

R. Reich, 'Atiqot 17 (1985), 206- 212

G. Finkielsztejn, RB 93 (1986), 419-428

L. Holland, American Numismatic Society Museum Notes 31 (1986), 171-201

R. Wenning,Boreas-Munstersche Beitriige zur Archiiologie9(1986), 113-129

MdB 56 (1988)

R. Arav, PEQ 121 (1989), 144-148

A. Raban, BASOR 273 (1989), 83

Y. Porathet al., ES/9 (1989-1990), 132-134

2nd International Congress on Biblical Archaeology, 24 June-4 July 1990: Abstracts, Jerusalem 1990, 104-112

G. Labbe, Revue des Etudes Anciennes 93 (1991), 277-297.

Italian Expedition

Main publication

A. Frova et al., Scavi di Caesarea Maritima, Milan 1965.

Other studies

Caesarea Maritima (Israele), Rapporto preliminare della 1-a campagna di scavo della Missione Archeologica Italiano, Milan 1959

A. Frova, CNI 14/3-4 (1963), 20-24

id., Scavi di Caesarea Maritima (Reviews), AlA 71 (1967), 323-324.- Archaeology 20 (1967), 155.- Qadmoniot 7 (1969), 106-107 (Hebrew).

Hebrew University Expedition

M. Avi-Yonah, JEJ 6 (1956), 260-261

12 (1962), 137-139

13 (1963), 146-148

16 (1966), 135-141

20 (1970), 203-208

id., The Teacher's Yoke (H. Trantham Fest.), Waco, Texas 1964, 46-57

A. Negev, CNI 11/4 (1960), 17-22

id.,IEJIO (1960) 127, 264-265

II (1961), 81-83

13 (1963), 146-148

14 (1964), 237- 249

id., BTS 41 (1961), 6-15

id., ILN (Oct. 26, 1963), 684-686

(Nov. 2, 1963), 728-731

id., Ariel!6 (1966), 19-22

id., RB 78 (1971), 247-263.

The Theater

Main publications

A. Frova, Caesarea Maritima, Milan 1959

id. et al., Scavi di Caesarea Maritima, Milan 1965, 55-244

F. P. Parten Palange, Le Lucerne del Teatro di Caesarea Maritima, Rome (in prep.).

Other studies

A. Frova, Annvario della Scuola Archeologica di Atene 39-40 (1961-1962), 649-657

id., Note alia Va campagna di scavo, Rend. 1st Lombardia, Milan 1963

id., Quattro campagne di scavo della Missione Milanese a C.M., La Lombardia e !'Oriente, Milan 1963

id., ILN (April4, 1964), 524-526

A. Albricci, Bol/etino d'Arte 1962

H. Plommer, Levant 15 (1983), 132-140

A. Segal, Scripta Classica Israe/ica 8-9 (1985-1988), 145-165.

The circus

J. Jeremias, ZDPV 54 (1931), 279-289

B. Lifshitz, Revue des Etudes Grecques, 70/329-330 (1957), 118-130

J. H. Humphrey, BASOR 213 (1974), 2-45

218 (1975), 1-24

id., Roman Circuses, London 1986, 477-491

J. Riley, BASOR 218 (1975), 25-63

K. Vine and G. Hartelius, The Archaelogy of Jordan and Other Studies (S. H. Horn Fest.), Berrien Springs, Mich. 1986, 365-428.

The synagogue

E. L. Sukenik, Rabinowitz Bulletin I (1949), 17

2 (1951), 28-30

M. Schwabe, IEJ I (1950-1951), 49-53

3 (1953), 127-130

M. Avi-Yonah, Rabinowitz Bulletin 3 (1960), 44-48

id., IEJ6 (1956), 260-261

12 (1962), 137-139

13 (1963), 146-147

id., The Teacher's Yoke (Trantham Memorial Volume), Waco, Texas 1964, 46-57

B. Lifshitz, RB 72 (1965), 106-107

L. I. Levine, Roman Caesarea (Qedem 2), Jerusalem 1975, 40-45.

The aqueduct

H. Hamburger, IEJ9 (1959), 188-190

A. Negev, ibid. 14 (1964), 237-249

22 (1972), 52- 53

D. Barag,ibid. 14(1964), 250-252;J. Ringel, RB81 (1974), 597-600

Y. Olami (andY. Ringel), IEJ25 (1975), 148-150

id. (andY. Peleg), ibid. 27 (1977), 127-137

Y. Peleg, Leichtweiss-Institut Mitteilungen 82 (1984), 1-6

89 (1986), 1-15

Y. Nir, Harbour Archaeology (ed. A. Raban), Oxford 1985, 185-194; P. Mayerson, IEJ 36 (1986), 269-272

Y. Porath (and S. Yankelevitz), ESI 9 (1989-1990), 130-131.

Bibliography from Stern et al (2008)

Main publications

Caesarea Papers: Straton’s Tower, Herod’s Harbour, and Roman and Byzantine Caesarea (JRA Suppl. Series 5

ed. R. L. Vann), Ann Arbor, MI 1992

Caesarea Papers, 2: Herod’s Temple, The Provincial Governor’s Praetorium and Granaries, The Later Harbour, A Gold Coin Hoard and Other Studies (JRA Suppl. Series 35

eds. K. G. Holum et al.), Portsmouth, RI 1999

ibid. (Review) AJA 106 (2002), 107–110

Caesarea Papers, 3 (JRA Suppl. Series

eds. K. G. Holum & A. Raban), Portsmouth, RI 2003 (in press)

Y. Roman, Herod’s Masterpieces: Eretz Guide to the Caesarea National Park, Givatayim 1992

A. Raban et al., The Combined Caesarea Expeditions: Field Report of the 1992 Season, 1–3 (The Recanati Center for Maritime Studies Publications 4), Haifa 1993

The Harbours of Caesarea Maritima: Results of the Caesarea Ancient Harbour Excavation Project 1980–1985, II: The Finds and the Ship (University of Haifa, Center for Maritime Studies Publication 5

BAR/IS 594

ed. J. P. Oleson), Oxford 1994

Caesarea: A Mercantile City by the Sea (Reuben and Edith Hecht Museum Catalogue 12), Haifa 1995

E. E. Myers, Caesarea Maritima: A Bibliography, Toronto 1995

R. J. Painter, Mithraism and the Religious Context at Caesarea Maritima (Ph.D. diss., Southern Baptist Theological Seminary, 1994), Ann Arbor, MI 1995

Y. Arnon, International Commercial Activity of Caesarea during the Early Islamic II Period (749–969 C.E.) According to the Ceramic Evidence (M.A. thesis), Haifa 1996 (Eng. abstract)

Caesarea Maritima: A Retrospective after Two Millennia (Documenta et Monumenta Orientis Antiqui 21

eds. A. Raban & K. G. Holum), Leiden 1996

ibid. (Reviews) BASOR 308 (1997), 108–110. — IJNA 26 (1997), 263–264. — Minerva 9 (1998), 52–53. — PEQ 130 (1998), 84–85. — BAR 25/2 (1999), 59. — JRA 13 (2000), 671–677

M. A. Fitzgerald, A Roman Wreck at Caesarea Maritima, Israel: A Comparative Study of its Hull and Equipment (Ph.D. diss., Houston 1995), Ann Arbor, MI 1996

Israel Nature and National Parks Protection Authority, Caesarea: Queen of the Coast (National Parks of Israel), Ramat-Gan 1996

R. Linn, Scientific Investigation of the Roman and Early Byzantine Wall Paintings of Caesarea, Israel (M.A. thesis), London 1996

R. Toueg, The Inner Harbour Basin of Caesarea (M.A. thesis), Haifa 1996 (Eng. abstract)

E. Black, Maritime Archeology: From Site to Presentation—The Case of Caesarea Maritima, Israel (M.A. thesis), York 1997; D. M. Everman, The Water Supply System of Caesarea Maritima: A Historical Study (Ph.D. diss.), College Park, MD 1997

A. Zemer, From the Treasures of Caesarea (National Maritime Museum Catalogue), Haifa 1997

The Richness of Islamic Caesarea (Reuben & Edith Hecht Museum Catalogue 15

ed. A. Raban), Haifa 1999

The Sdot-Yam Museum Book of the Antiquities of Caesarea Maritima (ed. R. Gersht), Tel Aviv 1999 (Eng. abstracts)

C. M. Lehmann & K. G. Holum, The Greek and Latin Inscriptions of Caesarea Maritima (The Joint Expedition to Caesarea Maritima Excavation Reports 5), Boston, MA 2000

ibid. (Reviews) SCI 21 (2002), 323–327. — JRA 16 (2003), 665–668. — LA 53 (2003), 491–493. — AJA 108 (2004), 299–300. — JAOS 124 (2004), 414–416

I. Miran, Combining Magnetometry and 3-D Ground Penetration Radar (GRP) Imaging for Archaeological Mapping in Caesarea, Israel (M.A. thesis), Tel Aviv 2000

Religious Rivalries and the Struggle for Success in Caesarea Maritima (ed. T. L. Donaldson), Waterloo, ONT 2000; Y. Turnheim & A. Ovadiah, Art in the Public and Private Spheres in Roman Caesarea Maritima: Temples, Architectural Decoration and Tesserae (Rivista di Archeologia Suppl. 27), Roma 2002

Y. D. Arnon, Alternation and Continuity in the Early Islamic Pottery Types from the 7th Century to the 12th Century ce: The Caesarea Data as a Study Case (Ph.D. diss.), Haifa 2003

E. Ayalon, The Assemblage of Bone and Ivory Artifacts from Caesarea Maritima, Israel, 1st–13th Centuries ce, 1–2 (Ph.D. diss.), Ramat-Gan 2003 (Eng. abstract)

The Israel Antiquities Authority Excavations at Caesarea 1992–1999 (ed. Y. Porath), 1: Herod’s Circus at Caesarea

2: The W2S3 Bath-House and the Roman Domus

3: The Praetorium of Roman Judea/ Palestina at Caesarea, Jerusalem (in prep.).

Studies

R. J. Bull, BASOR Suppl. Studies 27 (1991), 69–94

id. (et al.), AASOR 51 (1994), 63–86

id., AJA 100 (1996), 370

R. Gersht, IEJ 41 (1991), 145–156

id., The Roman and Byzantine Near East, 1, Portsmouth, RI 1995, 108–120

id., ASOR Newsletter 46/3 (1996), 19

id., Assaph B/2 (1996), 13–26

B/6 (2001), 63–90

id., ‘Atiqot 28 (1996), 99–113

id., Classical Studies (D. Sohlberg Fest.

ed. R. Katzoff), Ramat-Gan 1996, 433–450

id., Homenaje a José M. Blazquez, Jerusalem 1996, 51–73

id., Michmanim 16 (2002), 43*–44*

N. Amitai-Preiss, ‘Atiqot 21 (1992), 171–172

R. L. Hohlfelder, ABD, 1, New York 1992, 798– 803

K. G. Holum, BASOR 286 (1992), 73–85

id., BAT II, Jerusalem 1993, 697–702

id., ASOR Newsletter 45/2 (1995), 19

46/3 (1996), 17

id., Jahrbuch für Antike und Christentum Ergänzungsband 20 (1995), 849–854

id., HUCMS News 23 (1996), 13–14

id., The Oxford Encyclopedia of Archaeology in the Near East, 1 (ed. E. M. Meyers), New York 1997, 398–404

id. (et al.), AJA 102 (1998), 792

id., Religious and Ethnic Communities in Later Roman Palestine (Studies and Texts in Jewish History and Culture 5

ed. H. Lapin), Bethesda, MD 1998, 155–177

id., ASOR Annual Meeting Abstract Book, Boulder, CO 2001, 21; ASOR Annual Meeting 2004, www.asor.org/AM/am.htm

id., BAR 30/5 (2004), 36–45, 47

id., NEA 67 (2004), 184–198

E. Krentz, JNES 51 (1992), 157–158, 220–221 (Reviews)

A. Mazar, ‘Atiqot 21 (1992), 105–108

MdB 75 (1992), 29

M. Peleg & R. Reich, ‘Atiqot 21 (1992), 137–170

Y. Roman, Eretz Magazine 7/3 (1992), 35–58

Eveline J. Van der Steen, PEQ 124 (1992) 66 (Review)

A. Ziegelmann & Y. Ne’eman, ‘Atiqot 21 (1992), 177–178

E. U. Hübner, ZDPV 109 (1993), 182–183 (Review)

R. R. Stieglitz, ibid., 646–651

A. Van der Heyden, Ariel, Eng. Series 93 (1993), 15–28

T. Rajak, BAIAS 13 (1993–1994), 68–70

id., The Talmud Yerushalmi and Graeco-Roman Culture, 1 (Texte und Studien zum antiken Judentum 71; ed. P. Schäfer), Tübingen 1998, 349–366

id., The Jewish Dialogue with Greece and Rome: Studies in Cultural and Social Interaction (Arbeiten zur Geschichte des Antiken Judentums und des Urchristentums 48), Leiden 2001

J. Chase, ASOR Newsletter 44/2 (1994)

A. Flinder, PEQ 126 (1994), 169–170 (Review)

F. L. Horton, Jr., ASOR Newsletter 44/2 (1994)

id., Fest. E. W. Hamrick (eds. J. M. O’Brien & F. L. Horton, Jr.), Lewiston, NY 1995, 150–166, 170–173

id., Galilee through the Centuries, Winona Lake, IN 1999, 377– 390

J. Patrich, ASOR Newsletter 44/2 (1994)

46/3 (1996), 16–17

id., AJA 100 (1996), 758–760

id., Annual Byzantine Studies Conference Abstracts, 24 (University of Kentucky 1998), 41

id., ESI 17 (1998), 50–57

id., LA 50 (2000), 363–382

52 (2002), 321–346

id., Proceedings of the 12th World Congress of Jewish Studies, Jerusalem, 29.7–5.8.1997, Division B: History of the Jewish People, Jerusalem 2000, 35*– 44*

id., Cathedra 102 (2001), 209

107 (2003), 213

id., JRA 14 (2001), 269–283

16 (2003), 456–459

id., MdB 136 (2001), 57

id., Urban Centers and Rural Contexts in Late Antiquity (eds. T. S. Burns & J. V. Eadie), East Lansing, MI 2001, 77–110

id., Welt und Umwelt der Bibel 6/21 (2001), 76–77

8/30 (2003), 66–69

id., Israel Museum Studies in Archaeology 1 (2002), 21–32

id., What Athens Has to Do with Jerusalem, Leuven 2002, 29–68

Y. Porath, ‘Atiqot 25 (1994), 188

id., ASOR Newsletter 45/2 (1995), 17

id., The Roman and Byzantine Near East 1, Ann Arbor, MI 1995, 15–27, 269–272

id., ESI 17 (1998), 39–49; 112 (2000), 38–46

113 (2001), 131*

116 (2004), 23*–24*

id., Michmanim 14 (2000), 17*–18*

id., JRA 16 (2003), 451–455

id., BAR 30/5 (2004), 24–35

id., SCI 23 (2004), 63–67

M. K. Risser, AJA 98 (1994), 324

101 (1997), 340

103 (1999), 301 (& J. DeRose Evans)

id., BA 59 (1996), 240

S. Sachs & R. J. Bull, ASOR Newsletter 44/2 (1994)

Archaeology in the Biblical World 3/1 (1995), 5

Y. Arnon, ASOR Newsletter 45/2 (1995), 18

46/3 (1996), 19

47/2 (1997), 22

id., HUCMS 24–25 (1998), 5–8

J. A. Blakely, ASOR Newsletter 45/2 (1995), 19

C. Christian & B. Heese, ASOR Newsletter 45/2 (1995), 18

M. Immerzeel, Jahrbuch für Antike und Christentum Ergänzungsband 20 (1995), 855–864

A. Kushnir-Stein, The Roman and Byzantine Near East, 1, Ann Arbor, MI 1995, 8–14

C. M. Lehmann, Preliminary Excavation Reports: Sardis, Bir Umm Fawakhir, Tell el-Umeiri, The Combined Caesarea Expeditions and Tell Dothan (AASOR 52

ed. W. G. Dever), Philadelphia 1995, 121–131

J. Magness, ibid., 133–145

id., ASOR Newsletter 47 (1997), 10

A. L. Slayman, Archaeology 48/2 (1995), 16

D. Strong, HUCMS 22 (1995)

V. Sussman, IEJ 45 (1995), 278–282

E. Adams, Archaeology 49/1 (1996), 32

M. R. Buyce, ASOR Newsletter 46/3 (1996), 17; C. Cope, ibid., 19

id., Archaeozoology of the Near East 5 (eds. H. Buitenhuis et al.), Groningen 2002, 316– 319

M. L. Fischer (& Z. Grossmark), EI 25 (1996), 106*–107*

id., Marble Studies, Konstanz 1998

R. Förtsch, Judaea and the Greco-Roman World in the Time of Herod in the Light of Archaeological Evidence, Göttingen 1996, 9–25

L. C. Kahn, ASOR Newsletter 46/4 (1996), 11

id., AJA 102 (1998), 406

id., Hellenic and Jewish Arts: Interaction, Tradition and Renewal. The Howard Gilman International Conference 1, Delphi, 1995 (ed. A. Ovadiah), Tel Aviv 1998, 123–143

Y. Ne’eman, ESI 15 (1996), 52–54

A. Ovadiah & S. Mucznik, LA 46 (1996), 375–380

P. Richardson, Herod: King of the Jews and Friend of the Romans (Studies on Personalities of the New Testament), Columbia, SC 1996

id., City and Sanctuary: Religion and Architecture in the Roman Near East, London 2002, 103–128

F. H. Stanley, Jr., ASOR Newsletter 46/2 (1996), 19

id. (et al.), Archeologia Viva 16 (1997), 20–34

id., AJA 104 (2000), 326

H. Von Hesberg, Judaea and the Greco-Roman World in the Time of Herod in the Light of Archaeological Evidence, Göttingen 1996, 9–25

A. G. Walmsley, Towns in Transition: Urban Evolution in Late Antiquity and the Early Middle Ages (eds. N. Christie & S. T. Loseby), Aldershot 1996, 126–158

F. E. Winter, Archaeology 49/6 (1996), 22

A. Bankoff, ASOR Newsletter 47/2 (1997), 22

A. M. Berlin, BA 60 (1997), 2–51

H. Bolewski & J. Bremer, Jüdischer Almanach 1996 (1997), 129–140

J. Geiger, ZDPV 113 (1997), 70–74

id., Cathedra 99 (2001), 208–209

Le opere fortificate de Erode il Grande, Firenze 1997

A. J. Boas, ESI 17 (1998), 77– 79

J. DeRose Evans (et al.), AJA 102 (1998), 405

103 (1999), 259, 301

P. Melmuk, ASOR Newsletter 48/1 (1998), 23

R. Polak, Annales du Congrès de l’Association Internationale pour l’Histoire du Verre 14 (1998), 238–242

B. Rochman, BAR 24/1 (1998), 18

D. W. Roller, The Building Program of Herod the Great, Berkeley, CA 1998

Z. Safrai, The Missing Century: Palestine in the 5th Century—Growth and Decline (Palestine Antiqua N.S. 9), Leuven 1998, (index)

N.Yaari, Journal of Mediterranean Studies 8 (1998), 73–83

U. ‘Ad, ‘Atiqot 38 (1999), 228–229

D. M. Jacobson, BAIAS 17 (1999), 67–76

A. Lester & Y. D. Arnon, L’Egypte Fatimide: son art et son histoire. Actes du Colloque, Paris, 28.4.-3.5.1998 (ed. M. Barrucand), Paris 1999, 233–248

A. Lichtenberger, Die Baupolitik Herodes des Grossen (Abhandlungen des Deutschen Palästina-Vereins 26), Wiesbaden 1999

V. Shalev, Historical Context, Structure and Function in the Churches of Palestine in Late Antiquity (Ph.D. diss.), Tel Aviv 1999 (Eng. abstract)

A. M. Vaccaro, Archéo 16/11 (189) (2000), 90–97

R. Pummer, Samaritan Researches: Proceedings of the Congress of the Société d’Etudes Samaritaines V/3, Sydney 2000, 29–53

A. Iamim, ASOR Annual Meeting Abstract Book, Boulder, CO 2001, 21

L. Lavan, Recent Research in Late-Antique Urbanism (JRA Suppl. Series 42

ed. L. Lavan), Portsmouth, RI 2001, 39–56

D. Moy, ASOR Annual Meeting Abstract Book, Boulder, CO 2001, 22–23

E. M. Smallwood, The Jews Under Roman Rule from Pompey to Diocletian: A Study in Political Relations, Boston 2001 (index)

J. Stabler, ASOR Annual Meeting Abstract Book, Boulder, CO 2001, 21

ASOR Annual Meeting 2004, www.asor.org/AM/am.htm

E. Ayalon (& Y. Dray), Michmanim 16 (2002), 39*–40*

id., From Hooves to Horns, From Mollusc to Mammoth: Manufacture and Use of Bone Artefacts from Prehistoric Times to the Present. Proceedings of the 4th Meeting of the ICAZ Worked Bone Research Group, Tallinn, 26–31.8.2003 (eds. H. Luik et al.), Tallinn 2005, 228–246

V. Noam, Cathedra 104 (2002), 189

M. Rosen-Ayalon, Art et archéologie islamiques en Palestine (Islamiques), Paris 2002, 79–84

S. Scham, Archaeology 55/5 (2002), 30

S. Shalev & M. Freund, Bulletin of the Israeli Academic Center in Cairo 25 (2002), 21–30

id., Metals and Society (BAR/IS 1061

eds. B. S. Ottaway & E. C. Wager), Oxford 2002, 83–97

R. Talgam, Michmanim 16 (2002), 39*

D. Jones, Minerva 14/1 (2003), 22– 24

Y. Elitzur, Ancient Place Names in the Holy Land: Preservation and History, Jerusalem 2004, 23–28

L. B. Kavlie, NEAS Bulletin 49 (2004), 5–14

E. Lefkovitz, Artifax 20/4 (2005), 5

A. Lewin, The Archaeology of Ancient Judea and Palestine, Los Angeles, CA 2005, 148–155

J. Pastor, For Uriel: Studies in the History of Israel in Antiquity (U. Rappaport Fest.

eds. M. Mor et al.), Jerusalem 2005, 77*–89*

A. Spaer, The Numismatic Chronicle 165 (2005), 285–286

J. Sudilovsky, BAR 31/6 (2005), 17

E. Netzer, The Architecture of Herod, the Great Builder, Tübingen (forthcoming).

The Coins

D. R. Schwartz, Studies in the Jewish Background of Christianity (Wissenschaftliche Untersuchungen zum Neuen Testament 60), Tübingen 1992, 167–181

D. M. Metcalf & L. Holland, INJ 12 (1992–1993), 94–103; 13 (1994–1999), 156–162

R. J. Bull & O. J. Storvick, BA 56 (1993), 116–120

J. Meshorer, BAT II, Jerusalem 1993, 141–146

id., Ancient Means of Exchange, Weights and Coins (Haifa, Reuben & Edith Hecht Museum Collection A), Haifa 1998

id., A Treasury of Jewish Coins from the Persian Period to Bar-Kochba, Jerusalem 2001

J. DeRose Evans, American Journal of Numismatics 5–6 (1993–1994), 97–104

id., AJA 98 (1994), 312

id., ASOR Newsletter 45/2 (1995), 17

id., BA 58 (1995), 156–167

P. Lampinen, ASOR Newsletter 44/2 (1994)

id., ASOR Annual Meeting Abstract Book, Boulder, CO 2001, 20–21

S. L. Dyson, Archaeology 51/2 (1998), 6

A. Burnett et al., Roman Provincial Coinage II/1: From Vespasian to Domitian (AD 69–96), London 1999, 96

M. S. K. Prieur, A Type Corpus of the Syro-Phoenician Tetradrachms and Their Fractions from 57 BC to AD 253, London 2000

A. Eidelstein, INJ 14 (2000–2002), 245–247

M. G. Abramzon, Revue Numismatique 159 (2003), 243–256

H. Gitler & D. Weisburd, Les villages dans l’empire byzantin (IVe–XVe siècle) (Réalités Byzantines 11

eds. J. Lefort et al.), Paris 2005, 539–552

The Inscriptions

G. Labee, Revue des Etudes Anciennes 93 (1991), 277–297

L. Di Segni, ‘Atiqot 22 (1993), 133–136

id., Dated Greek Inscriptions from Palestine from the Roman and Byzantine Periods (Ph.D. diss.), 1–2, Jerusalem 1997

id., Atti della 11. Congresso Internazionle de Epigrafia Greca e Latina, Roma, 18–24. 9. 1997, Roma 1999, 625–642

id., LA 50 (2000), 383–400

id., Israel Museum Studies in Archaeology 1 (2002), 33–38

C. M. Lehmann, BAT II, Jerusalem 1993, 679–686

D. Barag, ‘Atiqot 25 (1994), 179–181

L. Boffo, Iscrizioni greche e latine per lo studio della Bibia (Biblioteca di storia e storiografia dei tempi Biblici 9), Brescia 1994

K. G. Holum, The Roman and Byzantine Near East, 1, Portsmouth, RI 1995, 333–345

W. Horburg, PEQ 129 (1997), 133–137

A. Lajtar, Materialy Archeologiczne (Krakow) 30 (1997), 61–65

B. Burrell, NEA 61 (1998), 127–128

G. Alföldy, SCI 18 (1999), 85–108

21 (2002), 133–148

H. M. Cotton & W. Eck, Israel Academy of Sciences and Humanities, Proceedings 7 (2001), 215–240

id., What Athens Has to Do with Jerusalem, Leuven 2002, 375–391

B. Isaac, JRA 16 (2003), 665–668.

The Promontory Palace

K. L. Gleason (et al.), AJA 96 (1992), 345

id. (& B. Burrell), ASOR Newsletter 44/2 (1994)

45/2 (1995), 19; 46/2 (1996), 18–19

46/3 (1996), 10–11

id., Caesarea Maritima: A Retrospective after Two Millennia (op. cit.), Leiden 1996, 208–228

id., JRA 11 (1998), 23–52

B. Burrell & K. Gleason, AJA 97 (1993), 342

99 (1995), 306–307

101 (1997), 339–340

102 (1998), 405

106 (2002), 107–110

id. (et al.), BAR 19/3 (1993), 50–57

id., ESI 14 (1994), 75

id., Caesarea Maritima: A Retrospective after Two Millennia (op. cit.), Leiden 1996, 228–247

I. Nielsen, Hellenistic Palaces: Tradition and Renewal (Studies in Hellenistic Civilization 5), Aarhus 1994

E. Robinson, ASOR Newsletter 45/2 (1995), 17

E. Netzer, Caesarea Maritima: A Retrospective after Two Millennia (op. cit.), Leiden 1996, 193–206

id., Judaea and the Greco-Roman World in the Time of Herod in the Light of Archaeological Evidence, Göttingen 1996, 27–54

id., Die Paläste der Hasmonäer und Herodes’ des Grossen (Antike Welt Sonderhefte

Zaberns Bildbände zur Archäologie), Mainz am Rhein 1999

id., The Architecture of Herod, the Great Builder, Tübingen (forthcoming)

L. L. Taylor, AJA 102 (1998), 405–406

Y. Turnheim & A. Ovadiah, Assaph B/4 (1999), 21–34

J. Ramsay, ASOR Annual Meeting Abstract Book, Boulder, CO 2001, 22

J. G. Schryver, ASOR Newsletter 52/3 (2002), 14–15

J. Neguer, Mosaics Make a Site: The Conservation in Situ of Mosaics on Archaeological Sites. Proceedings of the 6th Conference of the International Committee for the Conservation of Mosaics, Nicosia, 24–28.10.1996 (ed. S. Michaelides), Rome 2003, 375–378

id., Conservation and Management of Archaeological Sites 6/3–4 (2004), 247–258

K. G. Holum, BAR 30/5 (2004), 36–45, 47

J. A. Stabler, ASOR Annual Meeting 2004, www.asor.org/AM/am.htm

Y. Olami et al., Map of Binyamina (48) (Archaeological Survey of Israel), Jerusalem 2005, 37*, 41*–43*.

The Synagogue

I. L. Levine, BAT II, Jerusalem 1993, 666–678

id., Caesarea Maritima: A Retrospective after Two Millennia (Documenta et Monumenta Orientis Antiqui 21

eds. A. Raban & K. G. Holum), Leiden 1996, 392–400

id., The Ancient Synagogue: The First Thousand Years, 2nd ed., New Haven, CT 2005, 68

M. Govaars, ASOR Annual Meeting 2004, www.asor.org/AM/am.htm.

The Water Supply

Y. Porath (et al.), ESI 9 (1980–1990), 130–131

12 (1993), 28–29

112 (2000), 34*–40*

id., ‘Atiqot 30 (1996), 126–127

id., The Aqueducts of Israel, Portsmouth, RI 2002, 105–129

J. Peleg, Geschichte der Wasserwirtschaft und des Wasserbaus im Mediterraneen Raum. 8. Internationalen Symposium, 12–20.10.1991, Merida, Spanien. (Mitteilungen Leichtweiss-Institut für Wasserbau des Technischen Universität Braunschweig 117), Braunschweig 1992, 141–156

id., Caesarea Papers, 2 (op. cit.), Portsmouth, RI 1999, 361–367; id., The Aqueducts of Israel, Portsmouth, RI 2002, 141–148

U. ‘Ad, ‘Atiqot 38 (1999), 228

K. K. A. Lonnqvist, Klio 82 (2000), 459–474

A. Siegelmann, The Aqueducts of Israel, Portsmouth, RI 2002, 130–140

J. Häser, SHAJ 8 (2004), 155–159

D. Sivan et al., Earth and Planetary Science Letters 222 (2004), 315–330; Y. Olami et al., Map of Binyamina (48) (Archaeological Survey of Israel), Jerusalem 2005, 37*, 41*–43*.

Maritime Caesarea

A. Raban (& K. G. Holum), ESI 10 (1991), 109–112

17 (1998), 58–76

20 (2000), 34*–36*

id., Thracia Pontica 4 (1991), 339–366

5 (1994), 241–268

6 (1997), 207–244

id., HUCMS 19 (1992), 4–7

20 (1993), 1–4, 5–6

21 (1994)

22 (1995)

23 (1996), 10–13

24–25 (1998), 31–33

26 (1999), 9–12 (& K. G. Holum); 27 (2000), 6–11

29 (2002–2003), 11–14

30 (2004), 14–17

id., IJNA 21 (1992), 27–35, 111–124

29 (2000), 260–272

id., The Maritime Holy Land: Mediterranean Civilization in Ancient Israel from the Bronze Age to the Crusaders, Haifa 1992, 71–79

id. (et al.), IEJ 43 (1993), 29–34

id. (et al.), AJA 98 (1994), 506–509; 105 (2001), 299

id., ASOR Newsletter 44/2 (1994)

45/2 (1995), 17

id., Sefunim 8 (1994), 45–59

id., Antike Welt Sondernumer 26 (1995), 14–29

id., Michmanim 8 (1995), 15*–16*

id., Cyprus and the Sea: Proceedings of the International Symposium, Nicosia, 25–26 Sept. 1993 (ed. V. Karageorghis & D. Michaelides), Nicosia 1995, 139–188

id., BAR 23/3 (1997), 42–45

id., Archeologia Subacquea: come opera l’Archeolgo storie dalle acque (Ciclo di lezioni sulla ricerca in archeologia certosa di pontignago 8

ed. G. Volpe), Firenze 1998, 217–273

id., ASOR Annual Meeting Abstract Book, Boulder CO 2001, 21–22

id., For Uriel: Studies in the History of Israel in Antiquity (U. Rappaport Fest.

eds. M. Mor et al.), Jerusalem 2005, 181*–187*

id., Building Projects of Herod the Great, London (in press)

id. (et al.), Journal of Coastal Geomorphology (in press)

id., The World of the Herods (ed. N. Kokkinos), London 2003 (in press)

Y. Hirschfeld, JRA 5 (1992), 445–449 (Review)

R. L. Hohlfelder, ABD, 1, New York 1992, 798–803

id., AJA 97 (1993), 342

id., BASOR 290–291 (1993), 95–107

317 (2000), 41–62

id., BAT II, Jerusalem 1993, 687–696

id., Ancient History in a Modern University, 1 (eds. T. W. Hillard et al.), Grand Rapids, MI 1998, 316–327

id., IJNA 28 (1999), 154–163

id., JNES 59 (2000), 241–253

J. P. Oleson & G. Branton, Geschichte der Wasserwirtschaft und des Wasserbaus im Mediterraneen Raum. 8. Internationalen Symposium, 12–20.10.1991, Merida, Spanien (Mitteilungen Leichtweiss-Institut für Wasserbau des Technischen Universität Braunschweig 117), Braunschweig 1992, 387–420

Galili et al., IJNA 22 (1993), 61–77

Y. Mart, HUCMS 20 (1993), 4

id. (& I. Percecman), Tectonophysics 254 (1996), 139–153

R. L. Vann, BAT II, Jerusalem 1993, 653–665

id., IEJ 43 (1993), 29–34

id., Jahrbuch für Antike und Christentum Ergänzungsband 20 (1995), 1239–1246

id., JRA 13 (2000), 671–677

C. Brandon, Thracia Pontica 6 (1994), 45–68

id., Cahiers d’Archéologie subaquatique 13 (1997), 13–34

id., Res Maritimae: Cyprus and the Eastern Mediterranean from Prehistory to Late Antiquity (CAARI Monograph Series 1

ASOR Archaeological Reports 4

eds. S. Swiny et al.), Atlanta GA 1997, 45–58

E. G. Reinhardt, AJA 98 (1994), 340–341

id. (et al.), Journal of Foraminiferal Research 24 (1994), 37–48

id. (et al.), Revue Paléobiologique 17 (1998), 1–21

id. (& A. Raban), Geology 27 (1999), 811–814; id., ASOR Annual Meeting Abstract Book, Boulder, CO 2001, 22

B. Yule, ASOR Newsletter 45/2 (1995), 17

id., Levant 28 (1996), 210

S. A. Kingsley, AJA 100 (1996), 765

id. (& K. Raveh), The Ancient Harbour and Anchorage at Dor, Israel: Results of the Underwater Surveys 1976–1991 (BAR/IS 626), Oxford 1996; id., Recent Research in Late-Antique Urbanism (JRA Suppl. Series 42

ed. L. Lavan), Portsmouth, RI 2001, 69–87

id., Minerva 16/5 (2005), 14–15

Encyclopaedia of Underwater and Maritime Archaeology (ed. J. P. Delgado), London 1997, 80–81

T. W. Hillard & J. L. Beness, Res Maritimae (op. cit.), Atlanta, GA 1997, 135–151

M. Maischberger, Marmor in Rom: Anlieferung, Leger-und Werkplätze in der Kaiserzeit (Palilia 1), Wiesbaden 1997

R. Toneg, HUCMS 24–25 (1998), 16–18

D. Gil, Annual Meeting, Israel Geological Society, Jerusalem 1999

C. Nixon, HUCMS 28 (2001), 4–9

J. A. Toth, Acta Archaeologica (Budapest) 53 (2002), 85–118

L. Brink, ASOR Annual Meeting 2004, www.asor.org/AM/am.htm

K. G. Holum, BAR 30/5 (2004), 36–45, 47

D. Sivan et al., Earth and Planetary Science Letters 222 (2004), 315–330

J. I. Boyce et al., IJNA 33 (2004), 122–136

B. N. Goodman & E. Reinhardt, 31st Archaeological Conference in Israel, Tel Aviv, 20–21.4.2005: Abstracts of Papers, Jerusalem 2005, 12.

Notes from Ambraseys (2009) on the 551 CE Earthquake

Caesarea Maritima, 80 km south of Tyre and on the coast, suffered severe damage in AD 614 and 640 according to stratigraphic and historical evidence (Russell 1985, 23). Russell argues that the destruction is too severe to be the result of a Persian invasion, as [Toombs (1978)] has said, so it must be due to the AD 551 and 632/3 earthquakes. It is certainly geographically possible, he adds, that Caesarea suffered in this event, being only about 100 km south of Tyre and the same distance (as Tyre) from the Dead Sea fault.

Was there Liquefaction at Area LL during the mid 8th century CE Earthquake ? - Photos and Notes by JW

Maps, Photos, Sections, and Plans

Maps, Photos, Sections, and Plans

  • Fig. 2 Aerial view of site LL from Ad et al (2018)
  • Fig. 3 Early phases Plan of Area LL from Ad et al (2018)
  • Fig. 4 Building remains and Roman floors in a probe, looking north Ad et al (2018)
  • Fig. 8 Wall Collapse in Stratum VI (Umayyad) from Ad et al (2018)
  • Sandy Deposits Just north of Area LL
  • View into room below warehouses
  • Beach and Western Wall of the Warehouses in Area LL - View from South
  • Beach and Western Wall of the Warehouses in Area LL - View from North

Discussion

The warehouses of Area LL were built on the beach in the north part of the harbour of Caesarea. The underlying sediments are loose unconsolidated and fully saturated beach sands. There are un-excavated rooms beneath the warehouses in Area LL. Some of the sands above the beach are exposed so I examined them. They are soft, loose, and unconsolidated. This location should be highly susceptible to liquefaction during seismic shaking. I do not know how deep the original foundations were sunk.

Notes

  • 0.1 g is sufficient to cause a submarine landslide.
  • Tsunami and Civil Engineering slope stability equations may refine this
  • There is an offshore slope break from Akhziv down to Gaza capable of generating tsunamis.
  • Dey et al (2014) reports underwater slumps offshore from Palmachim and Akhziv which are located adjacent to the shelf slopes.
  • There is also something known as the Dor disturbance (interview with Beverly Goodman in Haaretz).

Tsunamigenic and non-Tsunamigenic Deposits in Caesarea (Galili et al, 2021)

Galili et. al. (2021)

Figures
Figures

  • Fig. 4 - The Roman, Herodian harbor of Caesarea from Galili et al (2021)
  • Fig. 5 - The Caesarea region from Galili et al (2021)
  • Fig. 6 - Aerial photo of the Caesarea coast from Galili et al (2021)
  • Fig. 14 - Deposit of broken pottery in the Roman circus from Galili et al (2021)
  • Fig. 15 - Location of boreholes from Galili et al (2021)

Discussion

4.5.1. Archaeological Finds Presented as Evidence for a 2nd Century CE Tsunami Event

Mixed layers of sediment, described as garbage, were found in material excavated from the harbor. The excavations yielded some valuable artefacts, such as bronze figurines, and it has been argued that the supposed garbage is actually a mixture of marine and terrestrial sediment left behind by tsunami waves [42]. However, in ancient anchorages and harbors, along the shores of Israel and beyond, the remains of numerous vessels and cargoes of ancient ships were discovered, including bronze statues and valuables (e.g., in Akko harbor, [81]). Many ships have been wrecked in the Caesarea area over the years, as evidenced by numerous finds discovered in the harbor and nearby anchorages [41], (pp. 75–112, [48]), [59,82]. It is therefore more likely that the origins of the valuable artefacts discovered within the sediments in the port originated from ships that were wrecked in and around the harbor during storms, or they were objects that fell into the water during loading or unloading of the cargo. Such finds, common in ancient harbors, may not be interpreted as unequivocal evidence of a tsunami event.

4.5.2. Sedimentological Findings at Sea Presented as Indicators of a Tsunami

The core issue in tsunami sedimentology is to distinguish tsunami deposits from beach or storm deposits. Marine fauna and marine deposits found in low-lying, lagoonal water bodies near the coast are often used as paleo tsunami indicators, and so is the presence of large boulders on a rocky coast, away from the sea [42,83,84]. Identifying offshore tsunami deposits is more challenging. It has been less practiced, as there are very few analogies for comparison and it is hard to distinguish them from storm deposits [10,42,83]. A comprehensive study conducted by Mariner et al. [84] analyzed hundreds of published records of tsunami events in the Mediterranean and proposed that 90% of them are problematic and need to be re-examined.

4.5.3. Outside the Harbor

At a water depth of 10–12 m offshore, Reinhardt et al. (area W, [42]) identified beds of small angular shell fragments and potsherds dated from the 1st century BCE to the 1st century CE that were overlain by a layer of convex-up-oriented disarticulated bivalve shells. Relying on the fragmentation patterns and stratigraphy of the shells, the authors assumed that these shells could be related to the 115 CE tsunami deposits. Reinhardt et al. [42] also reported on the presence of articulated Glycymeris shells in the tsunami deposit, and suggested that these shells indicate transport from the deeper shelf, as the shallowest habitation depth for these bivalves is 18 m. However, no evidence for the presence of such articulated Glycymeris shells in the discussed deposits have ever been presented or published. Furthermore, Meinis et al. [85] noted that Glycymeris sp. (especially G. insubrica or violescens) were very common along the Israeli coast over long periods. They existed at different depths in a coastal environment (e.g., 8–16 m depth) and even at 200 m water depth. In the Adriatic Sea, their habitat was reported to be at a water depth of 2–40 m [86]. Moreover, Reinhardt et al. [42] give no explanation of how these articulated mollusks survived what they describe as the “…intense wave turbulence, shell-to-shell impacts, and shells striking the harbor moles or bedrock under high wave energy, as generated by a tsunami”. Given the above, there is nothing special in finding G. insubrica in sea bed sediments which are shallower than 18 m. The existence of articulated Glycymeris bivalves in the discased Caesarea deposits is yet to be proven, while the preservation of such articulated shells under a catastrophic tsunami that was assumed to destroy the Roman Harbor, is still to be explained.


As noted above, it is difficult to distinguish between tsunami and storm deposits [83,84,87,88]. Sakuna et al. [89] noted the difficulty in identifying the shallow-marine tsunami deposits associated with the 2004 Indian Ocean tsunami based on sedimentological evidence. Tamura et al. [10], who study the 2011 tsunami in Japan, concluded that this tsunami (“one of the largest modern tsunamis in the last 1200 years”) did not produce distinct sedimentary records in Sendai Bay. He also stated that there are no established unequivocal criteria for identifying shallow marine tsunami deposits and that it is impossible to identify the associated deposits at sea, since they are not preserved and might have been mixed by storms [10]. Their results agree with the suggestions of Weiss and Bahlburg [90] that the offshore tsunami deposits are unlikely to be preserved at depths shallower than 65 m. In this regard, the deposits identified by Reinhardt et al. [42] as the result of the 115 tsunami that is supposed to have destroyed the harbor, are questionable, as are the three reflected sub-bottom layers identified by Goodman-Tchernov and Austin [9] as tsunami features.

4.5.4. Tsunami Deposits in the Eastern (Inner) Basin

Excavations in the eastern basin [40] yielded a thin layer of sediments from the 1st to 2nd centuries CE, overlain by a deposit of mixed sediments. They determined that in the 1st century, and evidently up to the 3rd century CE, the prevailing conditions in the eastern basin were of a brackish body of water with good circulation. Thus, the inner harbor seems to have been in use after 115 CE. The mixed sediment deposits discovered in the eastern basin was attributed by Reinhardt and Raban [40] to cleaning and deepening of the harbor in early periods. The proposed main mechanisms for the destruction of the harbor in the study by Reinhardt and Raban [40] were the seismic and tectonic scenarios. Later, however, after reassessing the finds in light of the available new studies on tsunamis, the tectonic and seismic scenarios, as well as the dredging deposit hypothesis, gave way to the 115 CE tsunami scenario [42].

4.5.5. Tsunami Deposits on Land in Caesarea

It is reasonable to assume that a powerful tsunami, such as the one suggested to have occurred in 115 CE, should have affected other places along the Caesarea region and leave behind tsunamigenic deposits that can be traced on land in Caesarea and surrounding lowlands. Excavations carried out on the coast of Caesarea yielded deposits which were associated with 6th and 8th century CE tsunami events (Figure 14) [8,9]. However, so far, no tsunami deposits that can be attributed to the second century CE were reported from land excavations in Caesarea and around. Furthermore, boreholes taken in lowlands a few km north and south of Caesarea [91,92] (Figure 15) revealed no tsunami deposits that can be dated to 115 CE. Nonetheless, no evidence does not mean no event, and further searches for possible 115 CE tsunamigenic deposits on land is certainly needed.


...

4.6. Swell Storms

The winter wave climate along the Mediterranean coast of Israel is characterized by alternating periods of calm seas and storm events [23,101,102,103]. Since November 1993, high-quality directional wave data have been measured simultaneously offshore Ashdod and Haifa (75 km south of Caesarea, and 37 north of Caesarea respectively) by the Coastal and Marine Engineering Research Institute. At these sites, where the water depth is about 24 m, a Wave-rider buoy was deployed to acquire 30-min records of surface elevation and directional spectral information [104]. By using the Weibull distribution with a 3.7 m significant height (Hs) threshold, a statistical analysis of extreme wave events was recorded in Ashdod during the period of 1 April 1992 and 31 March 2015. The analysis shows that the significant wave height for the 20, 50 and 100-year return period are about 7.07 m, 7.75 m, 8.27 m and 8.78 m respectively [105], with a maximum height of over 13 m [23]. Furthermore, during the last 20 years, four major storms with Hs > 7 m were measured in Haifa in Feb 2001, Dec 2002, Dec 2010 and Feb 2015. The statistical analysis, as well as the last major events, show that the Israeli coast is affected by relatively high waves [106]. These storms also induced strong longshore currents that may exceed 2 m/sec [23,103,107]. Here we discuss the potential impact of those winter storms and longshore currents.

4.6.1. Wave-Induced Seabed Liquefaction

Deposits of man-made artifacts originating from shipwrecks, shells and other natural products can be sorted and stratified below the sandy seabed in various depths by storm waves. Wave-induced seabed liquefaction of the sandy sea bed occurs at depths of up to 30 m below sea level to a depth of 3 m below seabed due to wave storms (pp. 445–509, [108]; E. Kit pers. comm. 2021). The wave-induced seabed liquefaction is maximal at water depths of 8–9 m [108]. Such liquefaction results in settlement and re-solidification [109], and may lead to sorting and stratification of artifacts and other natural products in sub-bottom horizons. Thus, the three sub-bottom horizons reported by Goodman-Tchernov and Austin [9], should also be considered as a result of wave storms effects.

4.6.2. Scouring

Fredsøe and Sumer (pp. 5–6, [108]) noted that “when a structure is placed in a marine environment, the presence of the structure will change the flow pattern in its immediate neighborhood, resulting in several phenomena: (1) the generation of turbulence; (2) the occurrence of reflection and diffraction waves; (3) the occurrence of wave breaking; (4) the pressure differentials in the soil that may produce “quick” condition/liquefaction allowing material to be carried off by currents. These changes usually cause an increase in the local sediment transport capacity and thus lead to scouring (erosion), which poses a threat to the stability of the structure”. The repeating strong waves and the currents eroding the sandy seabed on which wave breakwaters are built on cause these constructions to disintegrate and settle into the loose sand. It is thus more reasonable to assume that the breakwaters of the western basin of Caesarea Harbor underwent settlement and destruction mainly due to extreme wave storms. The structures most probably settled down because the sand they were based on was liquefied and scoured away by the winter storms pounding waves and currents. Nonetheless, rare and random earthquake and tsunami events may have also contributed to the settlement of the breakwaters and the destruction of the harbor.

Notes by Jefferson Williams on the Deposit in the Roman Circus (Fig. 14 of Galili et. al., 2021)

Figures and Photos

Figures and Photos

  • Fig. 14 - Deposit of broken pottery in the Roman circus from Galili et al (2021)
  • Photo of the "archaeological deposit" in the Roman Circus
  • Explanatory Sign for the "archaeological deposit" in the Roman Circus

Discussion

Fig. 14 from Galili et al (2021) contains a photo of what is called the "Archaeological Deposit" at the Archaeological Park in Caesarea. It is located on the north side of the Roman Circus (aka the Hippodrome) and in the accompanying explanatory sign the deposits are dated to the 3rd and 4th centuries CE - i.e Late Roman and Early Byzantine. Dating is presumed to be derived from pottery and stratigraphy. Galili et al (2021)'s description of this deposit in the caption of Figure 14 is accurate.

Sea Level Fluctuations in Caesarea

Figures

Figures

  • Fig. 2 Herodian-phase mole showing the sea levels has been stable for ~2000 years from Dey et al(2014)
  • Fig. 4 The Roman, Herodian harbor of Caesarea from Galili et al (2021)
  • Fig. 5 The Caesarea region from Galili et al (2021)
  • Fig. 6 Aerial photo of the Caesarea coast from Galili et al (2021)

Discussion

Dey et al(2014) pointed out that the coastline at Caesarea appears to have been stable for the past ~2000 years (Fig. 2) with sea level fluctuating no more than ± 50 cm, no pronounced vertical displacement of the city's Roman aqueduct (Raban, 1989:18-21), and harbor constructions completed directly on bedrock showing no signs of subsidence.

Galili et al (2021:8-12) presented a wide array of evidence that also suggest Caesarea's coastline has been stable and sea level has been stable since at least the Hellenistic Period.
Archaeological and Geological Evidence for Sea-Level and Coastal Changes/Stability in Caesarea
Item Photos Description
The quay of the Hellenistic northern harbor of Straton’s Tower 6
7
The quay (Figures 6a and 7a), described by Raban (pp. 82–84, [48]) is built of headers. It is at an elevation that still enables functioning today, suggesting stable sea-level conditions since the 2nd century BCE.‎
Harbor wharves in the central basin 4
6
7
‎The wharves were built on the kurkar ridge and they retained their original level [41]: On the south-western side of this basin, a Roman quay was built of headers and it is presently at sea level (Figures 4(1) and 7b). Another quay was excavated by Raban on the northeastern side of this basin and was dated to the Herodian period (p. 86 and Figure 22, p. 115 and Figure 6, [48]) (Figures 4(2) and 7c). Both structures are currently at an elevation that enables functioning.
A surface built of large ashlars 4
7
‎The surface was discovered in the western basin at more than 5 m depth (Figures 4(3) and 7d). This structure was interpreted as a submerged pavement, supposedly indicating that the west basin of the harbor underwent tectonic subsidence and could no longer function as a port (p. 96 and Figure 38a,b [48]; [56–59]). This surface, however, could have been originally built underwater (see below).
Rock-cut Roman-palace pool 6
8
The rectangular basin in the southern palace (socalled Cleopatra pool) (Figures 6b and 8) (pp. 217–228, [60]), was interpreted as a swimming pool. It was operated by sea-water and its elevation still enables functioning today.‎
Roman harbor installations in the eastern basin 4 ‎A Roman mooring stone and staircase leading to it were found on the eastern quay of the eastern basin (p. 208, [46]) (Figure 4). Their elevation enables functioning today
Byzantine sewer outlet in the northern anchorage 6
9
‎The Byzantine sewer outlet has been ruined by the advancing sea (Figures 6c and 9). The ruins of this stone-built structure are now scattered along the sea bed to a distance of 35 m offshore. Originally, this indicates the location of the Byzantine coastline at the time that the sewer was still operating, some 1500 years ago. Its present location suggests that the coastline has shifted eastwards since the Byzantine period (p. 20, [41]) (Figures 6c and 9).
Water wells ‎A study of tens of water wells at Caesarea suggests that the sea level was constant in the last 2 ky, and that there were no tectonic changes in the region during that period [30,61].
Stone-built pool near Kibbutz Sedot-Yam 6
10
The rectangular stone-built pool that can be filled with sea water by gravity is currently at present sea level (Figures 6d and 10). Given its building style and location (close to the southern Byzantine city wall), it can be dated to the Byzantine period. The structure could have served as a swimming pool. ‎
Crusader mole in the northern part of the central basin 5
11
‎The Crusader mole was built of secondary-used pillars, which were placed on the flat, natural rock (probably abrasion platform). Its elevation enables functioning today (Figures 5d and 11).
Abrasion platforms 6 ‎North and south of the harbor, the coastal kurkar ridge was abraded by the sea and the abrasion platforms are at the same elevation as present sea levels (Figure 6e). The abrasion platforms and wave notches in Caesarea and along the entire Carmel coast suggest stable sea-level conditions over the last few thousand years, since sea levels reached their present elevation, ca. 4 ky ago [12,29].
Oysters on the quay of the eastern basin of the Roman harbor 4 ‎The mollusks attached to the stones suggest that during the Roman Period, the water level in the eastern basin was similar to that of today (p. 208, [46]) (Figure 4(5)).
Beachrock north of the northern Crusader wall 4
12
(Figures 4(6) and 12)—A 50 m long deposit of beach rock, with Roman marble chank traps in it, is attached to the kurkar‎ rock at present day sea-level elevations, suggesting stable sea-level conditions over the last two thousand years.
Beach rock ridge in the northern anchorage (Figures 6f and 9) 6
9
A massive strip of in-situ beach rock deposit, about 2.8 m-thick, is at 0.2–3.0 m below the present sea level. The deposit is located parallel to the coast, some 60 m west of the present shore and the remains of the aqueduct foundations (Figures 9 and 6f). This beachrock probably marks the location of the ancient coastline before the construction of the harbor and the aqueduct, and indicates that the shoreline has retreated horizontally some 60 m eastwards since the construction of the Roman aqueduct. This coastline shift must have occurred under stable sea-level conditions (p. 20, [41]).‎
References Cited by Galili et al (2021)
References

[12] Galili, E.; Sharvit, J. Ancient Coastal Installations and the Tectonic Stability of the Israeli Coast in Historical Times. In Coastal Tectonics; Stewart, I.S., Vita-Finzi, C., Eds.; Geological Society London, Special Publications: Oxford, UK, 1998; Volume 146, pp. 147–163.

[29] Galili, E.; Sevketoglu, M.; Salamon, A.; Zviely, D.; Mienis, H.K.; Rosen, B.; Moshkovitz, S. Late Quaternary morphology, beach deposits, sea–level changes and uplift along the coast of Cyprus and its possible implications on the early colonists. In Geology and Archaeology: Submerged Landscapes of the Continental Shelf; Harff, J., Bailey, G., Lüth, F., Eds.; Geological Society, London, Special Publications: London, UK, 2015; Volume 411, pp. 179–218.

[30] Sivan, D.; Lambeck, K.; Toueg, R.; Raban, A.; Porath, Y.; Shirman, B. Ancient coastal wells of Caesarea Maritima, Israel, an indicator for relative sea level changes during the last 2000 years. Earth Planet. Sci. Lett. 2004, 222, 315–330.

[41] Galili, E. Ancient harbors and anchorages in Caesarea. In Ancient Caesarea-Conservation and Development of a Heritage Site; Fuhrmann, Y.L., Porath, S., Eds.; Israel Antiquities Authority: Jerusalem, Israel, 2017; pp. 11–27.

[46] Toueg, R. The history of the inner harbour of Caesarea. In Treasures of Caesarea I; Ayalon, E., Izdarehet, A., Eds.; Keter: Jerusalem, Israel, 2011; pp. 205–216. (In Hebrew)

[48] Raban, A. The history of Caesarea harbors. In Treasures of Caesarea II; Porat, S., Ayalon, E., Izdarehet, A., Eds.; Keter: Jerusalem, Israel, 2011; pp. 75–112. (In Hebrew)

[56] Raban, A.; Holum, K.G. The lead ingots from the wreck site (area K8). J. Rom. Archaeol. Suppl. Ser. 1999, 35, 179–188.

[57] Raban, A. Marine Archaeological Research at Caesarea: Location of Evidence for Level Changes of Ancient Building Remnants; Final Report 2/76; Maritime Studies, University of Haifa: Haifa, Israel, 1976; pp. 7–58. (In Hebrew)

[58] Raban, A. Underwater excavations in the Herodian harbor Sebastos, 1995–1999 seasons. In Caesarea Reports and Studies: Excavations 1995–2007; BAR International Series 1784; Holum, K., Stabler, J., Reinhardt, E., Eds.; BAR International Series: Oxford, UK, 2008; pp. 129–142.

[59] Raban, A.; Artzy, M.; Goodman, B.; Gal, Z. (Eds.) The Harbour of Sebastos (Caesarea Maritima) in Its Roman Mediterranean Context; BAR International Series 1930; Archeopress: Oxford, UK, 2009.

[60] Netzer, E. The palace of the rock reef. In Treasures of Caesarea I; Ayalon, E., Izdarehet, A., Eds.; 2011; pp. 2017–2028. (In Hebrew)

[61] Vunsh, R. East Mediterranean Late Holocene Relative Sea-Level Changes Based on Archeological Indicators from the Coast of Israel. Master’s Thesis, Department of Maritime Civilizations, Faculty of Humanities, University of Haifa, Haifa, Israel, 2014. (In Hebrew, English Abstract)

Toe failure at northwest corner of Crusader Wall - Photos by JW

Photos

  • Toe Failure at Northwest Corner of Crusader Wall - Long shot - View from North
  • Toe Failure at Northwest Corner of Crusader Wall - A closer Long shot - View from North
  • Toe Failure at Northwest Corner of Crusader Wall - Medium shot - View from North
  • Toe Failure at Northwest Corner of Crusader Wall - Closeup - View from North

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