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

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 Roman's 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 birthplace 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).

Maps and Sections

Caesarea harbor overview from Dey and Goodman-Tchernov (2010)

Fig. 1

Caesarea harbor, overview (adapted from Boyce et al 2009)

Dey and Goodman-Tchernov (2010)
Map of core locations at Caesarea and Jisr al-Zikra

Fig. 1

Topographic map of the study area, depicting the Crocodile River position, aqueducts, dams, and Carmel Ridge in central Israel (adapted from Reinhardt et al., 2003)

Location map of sediment cores offshore Caesarea and Jisr al-Zarka: 1–3, 5, 6 (marked as black hexagons) and Area W underwater excavation (marked as a black square), isobaths are in meters. A surface sample from −50 m below sea level was also collected and is indicated by the * within the upper left inset.

Tyuleneva et al (2017)

from Tyuleneva et al (2017)
Fig. 3 - Location of sediment cores extracted in 2005 and 2007 from Dey and Goodman-Tchernov (2010)

Fig. 3

Location of sediment cores extracted in 2005 and 2007

Dey and Goodman-Tchernov (2010)
Core profile of Caesarea (offshore-harbor)

Fig. 4

Dip and strike CHIRP profiles (see Fig. 3), from which sample segments “a” and “b” have been enlarged for comparison with previously identified sediment core and underwater excavation stratigraphic compilations within the surveyed area (Reinhardt et al., 2006; Reinhardt and Raban, 2008; Goodman-Tchernov et al., 2009). Three horizons, representing four tsunami events, are recognizable from the available core evidence within the surveyed area (for core locations, see Fig. 1C).

Goodman-Tchernov and Austin (2015)

from Goodman-Tchernov and Austin (2015)
Core profile of Caesarea and Jisr al-Zikra

Fig. 8

Stratigraphic correlation of the core 6 offshore Jisr al-Zarka with representative core 2 (see Fig. 1) from Caesarea (adapted from Goodman-Tchernov et al., 2009). Sea level data are according to Sivan et al. (2001, 2004).

Tyuleneva et al (2017)

from Tyuleneva et al (2017)
Fig. 4 - Stratigraphic diagram of Core and Excavations from Dey and Goodman-Tchernov (2010)

Fig. 4

Summary of tsunamigenic characteristics identified in cores and excavations from the shore ('NS') and terrestrial area (`T') to greater depths

JW: Later publications redated Byzantine 551 A.D. to 749 .A.D. with possible reworked 551 A.D. deposits. If Roman 115 A.D. deposit is tsunamogenic, it was more likely caused by the early 2nd century Incense Road Earthquake rather than the distant 115 A.D. Trajan Quake

Dey and Goodman-Tchernov (2010)
Seismic Reflectors and evolution of Caesarea's harbor
Fig. 6

Structure maps of

the modern seafloor (top)

reflector “A” (middle)

reflector “B” (bottom)

To the right of each structure map, using observed channels in each map as a guide, we hypothesize tsunami-based outﬂow directions from the Caesarea harbor as it existed morphologically at three different times: ~1st–2nd century CE (115 CE), 6th–8th century CE (551/749 CE), and the present. The modern bathymetry reﬂects submerged harbor and coastal kurkar features. Major intact coastal features include Crusader-era city walls and moat. The 6–8th century A.D. (551 CE, 749 CE) “A” horizon includes multiple drainage-like features that are distributed more evenly along the coastline, which we suggest is a lack of a cohesive single harbor entrance and fewer monumental coastal structures. The horizon “B” structure map includes one or two pronounced channels, concentrated at the mouth of ancient harbor. We conclude that these features indicate focused backchanneling at the harbor entrance, with possibly an additional focal point on the southern side of harbor (possible association to sluice channels described by Raban, 1992).

Goodman-Tchernov and Austin (2015)
from Goodman-Tchernov and Austin (2015)

Link to Caesarea Archaeoseismic Site - Caesarea

Chronology

Summary of Tsunamigenic Events at Caesarea and Jisr al-Zikra

Shallow Seismic Survey and evolution of the harbor over time

Maps and Sections

Seismic Reflectors and evolution of Caesarea's harbor
Fig. 6

Structure maps of

the modern seafloor (top)

reflector “A” (middle)

reflector “B” (bottom)

To the right of each structure map, using observed channels in each map as a guide, we hypothesize tsunami-based outﬂow directions from the Caesarea harbor as it existed morphologically at three different times: ~1st–2nd century CE (115 CE), 6th–8th century CE (551/749 CE), and the present. The modern bathymetry reﬂects submerged harbor and coastal kurkar features. Major intact coastal features include Crusader-era city walls and moat. The 6–8th century A.D. (551 CE, 749 CE) “A” horizon includes multiple drainage-like features that are distributed more evenly along the coastline, which we suggest is a lack of a cohesive single harbor entrance and fewer monumental coastal structures. The horizon “B” structure map includes one or two pronounced channels, concentrated at the mouth of ancient harbor. We conclude that these features indicate focused backchanneling at the harbor entrance, with possibly an additional focal point on the southern side of harbor (possible association to sluice channels described by Raban, 1992).

Goodman-Tchernov and Austin (2015)
from Goodman-Tchernov and Austin (2015)

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.

1st - 2nd century CE tsunami

Maps and Sections

Map of core locations at Caesarea and Jisr al-Zikra

Fig. 1

Topographic map of the study area, depicting the Crocodile River position, aqueducts, dams, and Carmel Ridge in central Israel (adapted from Reinhardt et al., 2003)

Location map of sediment cores offshore Caesarea and Jisr al-Zarka: 1–3, 5, 6 (marked as black hexagons) and Area W underwater excavation (marked as a black square), isobaths are in meters. A surface sample from −50 m below sea level was also collected and is indicated by the * within the upper left inset.

Tyuleneva et al (2017)

from Tyuleneva et al (2017)
Core profile of Caesarea (offshore-harbor)

Fig. 4

Dip and strike CHIRP profiles (see Fig. 3), from which sample segments “a” and “b” have been enlarged for comparison with previously identified sediment core and underwater excavation stratigraphic compilations within the surveyed area (Reinhardt et al., 2006; Reinhardt and Raban, 2008; Goodman-Tchernov et al., 2009). Three horizons, representing four tsunami events, are recognizable from the available core evidence within the surveyed area (for core locations, see Fig. 1C).

Goodman-Tchernov and Austin (2015)

from Goodman-Tchernov and Austin (2015)

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.

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.

5th - 8th century CE tsunami

Maps and Sections

Map of core locations at Caesarea and Jisr al-Zikra

Fig. 1

Topographic map of the study area, depicting the Crocodile River position, aqueducts, dams, and Carmel Ridge in central Israel (adapted from Reinhardt et al., 2003)

Location map of sediment cores offshore Caesarea and Jisr al-Zarka: 1–3, 5, 6 (marked as black hexagons) and Area W underwater excavation (marked as a black square), isobaths are in meters. A surface sample from −50 m below sea level was also collected and is indicated by the * within the upper left inset.

Tyuleneva et al (2017)

from Tyuleneva et al (2017)
Core profile of Caesarea (offshore-harbor)

Fig. 4

Dip and strike CHIRP profiles (see Fig. 3), from which sample segments “a” and “b” have been enlarged for comparison with previously identified sediment core and underwater excavation stratigraphic compilations within the surveyed area (Reinhardt et al., 2006; Reinhardt and Raban, 2008; Goodman-Tchernov et al., 2009). Three horizons, representing four tsunami events, are recognizable from the available core evidence within the surveyed area (for core locations, see Fig. 1C).

Goodman-Tchernov and Austin (2015)

from Goodman-Tchernov and Austin (2015)
Core profile of Caesarea and Jisr al-Zikra

Fig. 8

Stratigraphic correlation of the core 6 offshore Jisr al-Zarka with representative core 2 (see Fig. 1) from Caesarea (adapted from Goodman-Tchernov et al., 2009). Sea level data are according to Sivan et al. (2001, 2004).

Tyuleneva et al (2017)

from Tyuleneva et al (2017)

Caesarea

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 551 CE Beirut Quake. The revision may be based on the analysis of apparent landward tsunami deposits

which were dated to around the time of the Sabbatical Year Quake(s) ( Dey et al, 2014). 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 our knowledge, been accomplished. Tsunamogenic evidence for the 551 CE Beirut Quake appears to be tenuous, while tsunamogenic evidence for an event in the mid 8th century CE appears to be better supported.

Jisr al-Zarka

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.

Tsunamigenic Effects

5th -8th century CE tsunami

Maps and Sections

Map of core locations at Caesarea and Jisr al-Zikra

Fig. 1

Topographic map of the study area, depicting the Crocodile River position, aqueducts, dams, and Carmel Ridge in central Israel (adapted from Reinhardt et al., 2003)

Location map of sediment cores offshore Caesarea and Jisr al-Zarka: 1–3, 5, 6 (marked as black hexagons) and Area W underwater excavation (marked as a black square), isobaths are in meters. A surface sample from −50 m below sea level was also collected and is indicated by the * within the upper left inset.

Tyuleneva et al (2017)

from Tyuleneva et al (2017)
Core profile of Caesarea (offshore-harbor)

Fig. 4

Dip and strike CHIRP profiles (see Fig. 3), from which sample segments “a” and “b” have been enlarged for comparison with previously identified sediment core and underwater excavation stratigraphic compilations within the surveyed area (Reinhardt et al., 2006; Reinhardt and Raban, 2008; Goodman-Tchernov et al., 2009). Three horizons, representing four tsunami events, are recognizable from the available core evidence within the surveyed area (for core locations, see Fig. 1C).

Goodman-Tchernov and Austin (2015)

from Goodman-Tchernov and Austin (2015)
Core profile of Caesarea and Jisr al-Zikra

Fig. 8

Stratigraphic correlation of the core 6 offshore Jisr al-Zarka with representative core 2 (see Fig. 1) from Caesarea (adapted from Goodman-Tchernov et al., 2009). Sea level data are according to Sivan et al. (2001, 2004).

Tyuleneva et al (2017)

from Tyuleneva et al (2017)

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.

Plots

Salamon and Di Manna Plot

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

Fig. 4.

Empirical ‘Magnitude-Distance’ bounding envelopes for tsunamis generated by seismogenic submarine landslides. Filled circles denote the distance from the seismogenic fault to the landslide scar (R_f), and empty circles denote the distance between the earthquake epicenter and the landslide scar (R_e). The bounding envelope of the maximal distance between the seismogenic fault and the landslide scar is delineated by line A and the bounding envelope between the epicenter and the landslide scar is denoted by the dashed line B.

Salamon and Di Manna (2019)

References

Elias, A., et al. (2007). "Active thrusting offshore Mount Lebanon: Source of the tsunamigenic A.D. 551 Beirut-Tripoli earthquake." Geology 35(8): 755-758.

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.

Calculators

Incense Road Earthquake

Attenuation Relationship is from Hough and Avni (2009)
Conversion from Intensity to PGA using Wald et al (1999)
0.1 g is sufficient to cause a submarine landslide.

Variable	Input	Units	Notes
Magnitude			Magnitude
R		km.	Distance to earthquake producing fault
Variable	Output - Site Effect not considered	Units	Notes
I		unitless	Local Intensity
PGA		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

Attenuation Relationship is from Hough and Avni (2009)
Conversion from Intensity to PGA using Wald et al (1999)
0.1 g is sufficient to cause a submarine landslide.

Variable	Input	Units	Notes
Magnitude			Magnitude
R		km.	Distance to earthquake producing fault
Variable	Output - Site Effect not considered	Units	Notes
I		unitless	Local Intensity
PGA		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

Attenuation Relationship is from Hough and Avni (2009)
Conversion from Intensity to PGA using Wald et al (1999)
0.1 g is sufficient to cause a submarine landslide.

Variable	Input	Units	Notes
Magnitude			Magnitude
R		km.	Distance to earthquake producing fault
Variable	Output - Site Effect not considered	Units	Notes
I		unitless	Local Intensity
PGA		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

Attenuation Relationship is from Hough and Avni (2009)
Conversion from Intensity to PGA using Wald et al (1999)
0.1 g is sufficient to cause a submarine landslide.

Variable	Input	Units	Notes
Magnitude			Magnitude
R		km.	Distance to earthquake producing fault
Variable	Output - Site Effect not considered	Units	Notes
I		unitless	Local Intensity
PGA		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

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.

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. 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.

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.

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.

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

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.

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.

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 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.

Mart, Y. and I. Perecman (1996). "Neotectonic activity in Caesarea, the Mediterranean coast of central Israel." Tectonophysics 254(1): 139-153.

Dey and Goodman, 2010, Mediterranean Tsunamis and the Port of Caesarea Maritima over the Longue Durée: A Geoarchaeological Perspective, Journal of Roman Archaeology 23 (2010)

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

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.

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)

Maps and Photos

The Roman, Herodian harbor of Caesarea
Figure 4

The Roman, Herodian harbor of Caesarea

left panel—aerial photo

right panel—artist reconstruction [43]
1. Roman dock
2. Roman dock
3. submerged surface built of ashlars
4. Crusader mole
5. Beachrock deposits
Galili et al (2021)
from Galili et al (2021)
The Caesarea region from Galili et al (2021)
Figure 5

The Caesarea region
1. Western harbor basin
2. Central harbor basin
3. Eastern harbor basin
Table 1 [41,43]

Galili et al (2021)
Aerial photo of the Caesarea coast from Galili et al (2021)
Figure 6

Aerial photo of the Caesarea coast
1. the location of Straton Tower quay
2. the rock-cut Roman palace pool
3. the Byzantine sewer outlet
4. the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9]
5. abrasion platforms
6. beachrock ridge marking the Roman coastline
7. the missing section of the aqueduct
Table 1 [41,43]

Galili et al (2021)

Galili et al (2021:16-17,20) discussed potential tsunamogenic deposits in Caesarea as follows

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

Fig. 14

A deposit of broken pottery in the Roman circus (up to 3 m thick):

general view, looking north-east (location of scale is marked with red arrow)

detailed view, looking west (scale in centimeters). Goodman-Tchernov and Austin [9] proposed that the fill consists of tsunamigenic deposits dated to the 6th and the 8th century CE. It should be noted that the excavator identified the deposit as Late Roman-Byzantine urban-waste fill (Porath Y. personal communication) (for location see Figures 6d and 15).

Galili et al (2021)

) [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

Fig. 15

Location of boreholes taken in coastal lowlands few kilometers south of the Caesarea harbor [91], and in Tanninim river outlet, few km north of the Caesarea harbor [92], and location of the Roman circus fill deposit

(Modified by E. Galili after Google Earth).

Galili et al (2021)

) 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 [23,101–103]. 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 subbottom 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.

References

[8] Dey, H.; Goodman-Tchernov, B.; Sharvit, J. Archaeological evidence for the tsunami of January 18, 749 Islamic: A chapter in the history of Early Caesarea, Qaysariyah (Caesarea Maritima). J. Rom. Archaeol. 2014, 27, 357–373.

[9] Goodman-Tchernov, B.N.; Austin, J.A., Jr. Deterioration of Israel’s Caesarea Maritima’s ancient harbor linked to repeated tsunami events identified in geophysical mapping of offshore stratigraphy. J. Archaeol. Sci. Rep. 2015, 3, 444–454.

[10] Tamura, T.; Sawai, Y.; Ikehara, K.; Nakashima, R.; Hara, J.; Kanai, Y. Shallow-marine deposits associated with the 2011 Tohoku-oki tsunami in Sendai Bay, Japan. J. Quat. Sci. 2015, 30, 293–297.

[23] Zviely, D. Sedimentological Processes in Haifa Bay in Context of the Nile Littoral Cell. Ph.D. Thesis, Department of Geography and Environment Studies, University of Haifa, Haifa, Israel, 2006. (In Hebrew, English Abstract)

[40] Reinhardt, E.; Raban, A. Catastrophic destruction of Herod the Great’s Harbor at Caesarea Maritima, Israel—Geoarchaeological Evidence. Geology 1999, 27, 811–814.

[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.

[42] Reinhardt, E.; Goodman, B.N.; Boyce, J.; Lopez, G.; van Hengstum, P.; Rink, W.J.; Mart, Y.; Raban, A. The tsunami of 13 December, A.D. 115 and the destruction of Herod the Great‘s harbor at Caesarea Maritima, Israel. Geology 2006, 34, 1061–1064.

[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)

[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.

[81] Silberstein, N.; Galili, E.; Sharvit, J. Chapter 3, Hellenistic, Roman and Byzantine Ceramics. In The Akko Marina Archaeological Project; Galili, E., Ed.; BAR Publishing: Oxford, UK, 2017; Volume 2862, pp. 320–344.

[82] Galili, E.; Dahari, U.; Sharvit, J. Underwater Survey and Rescue Excavations off the Israeli Coast. Int. J. Naut. Archaeol. 1993, 21, 61–77.

[83] Papadopoulos, G.A.; Gràcia, E.; Urgeles, R.; Sallares, V.; De Martini, P.M.; Pantosti, D.; Gonzálezd, M.; Yalcinere, A.C.; Masclef, J.; Sakellarioug, D.; et al. Historical and pre-historical tsunamis in the Mediterranean and its connected seas: Geological signatures, generation mechanisms and coastal impacts. Mar. Geol. 2014, 354, 81–109.

[84] Marriner, N.; Kaniewski, D.; Morhange, C.; Flaux, C.; Giaime, M.; Vacchi, M.; Goff, J. Tsunamis in the geological record: Making waves with a cautionary tale from the Mediterranean. Sci. Adv. 2017, 3, e1700485.

[85] Mienis, H.; Ben-David, Z.; Bar-Yosef, D.E. Glycymeris in the Levant sea, finds of recent Glycymeris Insubrica in the south corner of the Mediterranean Sea. Triton 2006, 13, 5–9.

[87] Pratt, B.R. Storms vs tsunamis: Dynamic interplay of sedimentary, diagenetic, and tectonic processes in the Cambrian of Montana. Geology 2002, 30, 423–426.

[88] Fujiwara, O.; Masuda, F.; Sakai, T.; Irizuki, T.; Fuse, K. Tsunami deposits in Holocene Bay mud in southern Kanto region, Pacific coast of central Japan. Sediment. Geol. 2000, 135, 219–230.

[89] Sakuna, D.; Szczucinski, W.; Feldens, P. Sedimentary deposits left by the 2004 Indian Ocean tsunami on the inner continental shelf offshore of Khao Lak, Andaman Sea (Thailand). Earth Planets Space 2012, 64, 931–943.

[90] Weiss, R.; Bahlburg, H.A. Note on the preservation of offshore tsunami deposits. J. Sediment. Res. 2006, 76, 1267–1273.

[91] Shtienberg, G. Morphological Changes in Caesarea’s Coastal Zone during the Last 2000 Years. Master’s Thesis, Department of Maritime Civilization, University of Haifa, Haifa, Israel, 2011. (In Hebrew, English Abstract).

[92] Avnaim-Katav, S.; Almogi-Labin, A.; Agnon, A.; Porat, N.; Sivan, D. Holocene hydrological events and human induced environmental changes reflected in a southeastern Mediterranean fluvial archive. Palaeogeogr. Palaeoclimatol. Palaeoecol. 2017, 468, 263–275.

[101] Rosen, D.S.; Kit, E. Evaluation of the Wave Characteristics at the Mediterranean Coast of Israel. Israel J. Earth Sci. 1982, 30, 120–134.

[102] Rosen, D.S.; Kaplan, A. Environmental loads design criteria for nearshore structures improved environmental loading design criteria for nearshore structures. In Proceedings of the 30th International Conference on Coastal Engineering; ASCE: San Diego, CA, USA, 2006; pp. 4456–4468.

[103] Kit, E.; Kroszynski, U. Marine Policy Plan for Israel: Physical Oceanography, Deep Sea and Coastal Zone Overview; P.N. 800/14; CAMERI—Coastal and Marine Engineering Research Institute, Technion City: Haifa, Israel, 2014.

[106] Bitan, M.; Zviely, D. Sand beach nourishment: Experience from the Mediterranean coast of Israel. J. Mar. Sci. Eng. 2020, 8, 273.

[107] Galili, E.; Weinstein-Evron, M. Rate of coastal transport along the southeastern Mediterranean coast during storms using water hyacinth. Geo Mar. Lett. 1989, 9, 103–108.

[108] Fredsøe, J.; Sumer, B.M. The Mechanics of Scour in the Marine Environment; Advanced Series on Ocean Engineering: Volume 17; World Scientific: Farrer Road, Singapore, 2002.

[109] Huang, Y.; Bao, Y.; Zhang, M.; Liu, C.; Lu, P. Analysis of the mechanism of seabed liquefaction induced by waves and related seabed protection. Nat. Hazards 2015, 79, 1399–1408.

Sea Level Fluctuations in Caesarea

Maps and Photos

The Roman, Herodian harbor of Caesarea (Fig. 4)
Figure 4

The Roman, Herodian harbor of Caesarea

left panel—aerial photo

right panel—artist reconstruction [43]
1. Roman dock
2. Roman dock
3. submerged surface built of ashlars
4. Crusader mole
5. Beachrock deposits
Galili et al (2021)
from Galili et al (2021)
The Caesarea region (Fig. 5) from Galili et al (2021)
Figure 5

The Caesarea region
1. Western harbor basin
2. Central harbor basin
3. Eastern harbor basin
Table 1 [41,43]

Galili et al (2021)
Aerial photo of the Caesarea coast (Fig. 6) from Galili et al (2021)
Figure 6

Aerial photo of the Caesarea coast
1. the location of Straton Tower quay
2. the rock-cut Roman palace pool
3. the Byzantine sewer outlet
4. the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9]
5. abrasion platforms
6. beachrock ridge marking the Roman coastline
7. the missing section of the aqueduct
Table 1 [41,43]

Galili et al (2021)

Dey et al(2014) pointed out that the coastline at Caesarea appears to have been stable for the past ~2000 years

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 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 Figure 6 Aerial photo of the Caesarea coast the location of Straton Tower quay the rock-cut Roman palace pool the Byzantine sewer outlet the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9] abrasion platforms beachrock ridge marking the Roman coastline the missing section of the aqueduct Table 1 [41,43] Galili et al (2021) 7 Figure 7 The Hellenistic quay at Straton’s Tower at elevation that enables functioning, looking south (for location see Figure 6) A Roman quay in the central basin, at an elevation that enables functioning today, looking west (for location see Figure 4 left panel, marked with number (1) A Roman quay built of ashlars in the central basin (for location see Figure 4 left panel, marked with number (2) A stone-built surface in the western basin, at 5 m below sea level (for location see Figure 4 left panel-marked with number (3). Galili et al (2021)	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 Figure 4 The Roman, Herodian harbor of Caesarea left panel—aerial photo right panel—artist reconstruction [43] Roman dock Roman dock submerged surface built of ashlars Crusader mole Beachrock deposits Galili et al (2021) 6 Figure 6 Aerial photo of the Caesarea coast the location of Straton Tower quay the rock-cut Roman palace pool the Byzantine sewer outlet the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9] abrasion platforms beachrock ridge marking the Roman coastline the missing section of the aqueduct Table 1 [41,43] Galili et al (2021) 7 Figure 7 The Hellenistic quay at Straton’s Tower at elevation that enables functioning, looking south (for location see Figure 6) A Roman quay in the central basin, at an elevation that enables functioning today, looking west (for location see Figure 4 left panel, marked with number (1) A Roman quay built of ashlars in the central basin (for location see Figure 4 left panel, marked with number (2) A stone-built surface in the western basin, at 5 m below sea level (for location see Figure 4 left panel-marked with number (3). Galili et al (2021)	‎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 Figure 4 The Roman, Herodian harbor of Caesarea left panel—aerial photo right panel—artist reconstruction [43] Roman dock Roman dock submerged surface built of ashlars Crusader mole Beachrock deposits Galili et al (2021) 7 Figure 7 The Hellenistic quay at Straton’s Tower at elevation that enables functioning, looking south (for location see Figure 6) A Roman quay in the central basin, at an elevation that enables functioning today, looking west (for location see Figure 4 left panel, marked with number (1) A Roman quay built of ashlars in the central basin (for location see Figure 4 left panel, marked with number (2) A stone-built surface in the western basin, at 5 m below sea level (for location see Figure 4 left panel-marked with number (3). Galili et al (2021)	‎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 Figure 6 Aerial photo of the Caesarea coast the location of Straton Tower quay the rock-cut Roman palace pool the Byzantine sewer outlet the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9] abrasion platforms beachrock ridge marking the Roman coastline the missing section of the aqueduct Table 1 [41,43] Galili et al (2021) 8 Figure 8 The rock-cut Roman pool in the reef palace, looking south (for location see Figure 6b). Galili et al (2021)	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 Figure 4 The Roman, Herodian harbor of Caesarea left panel—aerial photo right panel—artist reconstruction [43] Roman dock Roman dock submerged surface built of ashlars Crusader mole Beachrock deposits Galili et al (2021)	‎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 Figure 6 Aerial photo of the Caesarea coast the location of Straton Tower quay the rock-cut Roman palace pool the Byzantine sewer outlet the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9] abrasion platforms beachrock ridge marking the Roman coastline the missing section of the aqueduct Table 1 [41,43] Galili et al (2021) 9 Figure 9 Byzantine sewer outlet on the coast and partly submerged in the northern anchorage (marked with red arrows, for location see Figure 6c), and a beachrock ridge designating the location of the coastline before the construction of the harbor (marked with blue arrows, for location see Figure 6f), looking north. Galili et al (2021)	‎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 Figure 6 Aerial photo of the Caesarea coast the location of Straton Tower quay the rock-cut Roman palace pool the Byzantine sewer outlet the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9] abrasion platforms beachrock ridge marking the Roman coastline the missing section of the aqueduct Table 1 [41,43] Galili et al (2021) 10 Figure 10 Stone-built pool near Kibbutz Sedot-Yam, looking north-west (for location see Figure 5d) [43] Galili et al (2021)	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 Figure 5 The Caesarea region Western harbor basin Central harbor basin Eastern harbor basin Table 1 [41,43] Galili et al (2021) 11 Figure 11 . Crusader mole in the northern part of the central basin of the harbor: general view of the mole, built of secondary-used Roman pillars, looking west underwater photo of the pillars set on the kurkar abrasion platform (for location see Figure 4 left marked with number 4). Galili et al (2021)	‎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 Figure 6 Aerial photo of the Caesarea coast the location of Straton Tower quay the rock-cut Roman palace pool the Byzantine sewer outlet the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9] abrasion platforms beachrock ridge marking the Roman coastline the missing section of the aqueduct Table 1 [41,43] Galili et al (2021)	‎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 Figure 4 The Roman, Herodian harbor of Caesarea left panel—aerial photo right panel—artist reconstruction [43] Roman dock Roman dock submerged surface built of ashlars Crusader mole Beachrock deposits Galili et al (2021)	‎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 Figure 4 The Roman, Herodian harbor of Caesarea left panel—aerial photo right panel—artist reconstruction [43] Roman dock Roman dock submerged surface built of ashlars Crusader mole Beachrock deposits Galili et al (2021) 12 Figure 12 Beachrock north of the northern Crusader Wall: general view looking south close up of a Roman marble item consolidated in the beachrock (for location see Figure 4 left panel marked with number 5). Galili et al (2021)	(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 Figure 6 Aerial photo of the Caesarea coast the location of Straton Tower quay the rock-cut Roman palace pool the Byzantine sewer outlet the Roman circus and the location of the Late Roman-Byzantine urban-waste fill proposed by Goodman-Tchernov and Austin as a 6th and 8th century CE tsunami deposit [9] abrasion platforms beachrock ridge marking the Roman coastline the missing section of the aqueduct Table 1 [41,43] Galili et al (2021) 9 Figure 9 Byzantine sewer outlet on the coast and partly submerged in the northern anchorage (marked with red arrows, for location see Figure 6c), and a beachrock ridge designating the location of the coastline before the construction of the harbor (marked with blue arrows, for location see Figure 6f), looking north. Galili et al (2021)	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)

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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.

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.