Tilted Walls at Aila Jordan (southern Cyril Quake) Wall Collapse at Aila Jordan (southern Cyril Quake) Left - Tilted South Wall of Room 2 at Aila J-East

Right - Normal Faulting of a wall at Aila J-East

photos by Jefferson Williams


Introduction

Aila (aka Ailana) was the name of the Roman Byzantine town in Aqaba.

Maps and Plans
Maps and Plans

  • Map showing location of various sites around Aqaba including older sites from Allison (2013)
  • Map showing location of Islamic Ayla and Byzantine Aila (aka Ailana) from Whitcomb (1988)
  • Map showing location of Area J-east from Niemi (2014)
  • Plan of Area J-east from Thomas et al (2007)
  • Map showing Area B from Dolinka (2003:32)

Chronology
Phasing

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Thomas et al (2007) excavated and examined area J-east between 1994 and 2003. The J-East area is a multiphase site incorporating Early Islamic to Byzantine domestic occupation and a late third to fourth-century monumental mudbrick structure that has been interpreted as a church (Parker 1998a; 1999a; Mussell 2001; Rose 1998; Weintraub 1999) ( Thomas et al, 2007). This site, in the Roman-Byzantine town of Aila, is located ~500 m north of the modern shoreline of Aqaba and ~500 m NW of the Islamic town of Ayla . Thomas et al (2007) identified 6 or 7 earthquakes from the 2nd century CE onward in J-east and divided up the timing as follows:



Earthquake I - after mid to late 8th century CE

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Thomas et al (2007) described Earthquake II as follows:
The youngest earthquake (Earthquake I) recorded at this site ruptured faults very close to the modern ground surface.
...
The fault rupture of Earthquake I was capped by sand and disturbed modern car park construction deposits, thus preventing finer dating than post—mid to late eighth century.

Earthquake II - Abbasid - after mid to late 8th century CE

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Thomas et al (2007) described Earthquake II as follows:
These deposits were ruptured and the buildings collapsed.
...
The pottery within layers capping Earthquake II is earlier than that found in the occupation deposit beneath it. These data suggest that Earthquake II occurred after the mid to late eighth century A.D..

Earthquake III - Umayyad/Abassid - mid 7th - late 8th century CE

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Thomas et al (2007) described chronology as follows:
The fault rupture was capped by a later occupation dating to the mid to late eighth century. This dates Earthquake III between the mid seventh to mid, or possibly late, eighth century.
Since Earthquake IV was dated to the 7th and possibly 8th century and was likely due to one of the 7th century earthquakes (e.g. Sign of the Prophet Quake (613-624 CE), Sword in the Sky Quake (634 CE), or Jordan Valley Quake (659/660 CE) ), this suggests that Earthquake III was caused by one of the mid 8th century CE earthquakes.

Earthquake IV - Umayyad - 7th - 8th centuries CE

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Thomas et al (2007) identified earthquake destruction (Earthquake IV) in a collapse layer which they suggested struck in the early to middle 7th century CE.
The pottery constrains the date of Earthquake IV to sometime between the seventh century and the mid seventh to eighth century. In this case, an early to middle seventh-century date would best fit the dating evidence.

Earthquake V - Early Byzantine - 363 CE

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Thomas et al (2007) identified earthquake destruction (Earthquake V) in a collapse layer which they dated to the southern Cyril Quake. A terminus post quem of 360 CE for Earthquake V was established with coins and pottery.
Thin wall construction and surface layers produced pottery from the mid to late fourth century A.D. (similar types to Phase 2 described earlier). The latest pottery dates from about A.D. 360 onward (based on several examples of African Red Slip form 67, introduced ca. A.D. 360; Hayes 1972). However, over 100 coins were found on the final floor of this phase. The majority of these coins were found associated with the remains of a broken box in Room 2. The latest coins date to the reign of Constantius II who reigned from A.D. 337 to 361 (Parker 1999a) and provide a terminus post quem for this building phase.
They added
The very refined pottery and coin dates give a secure post A.D. 360 date for the Earthquake V event. The scarcity of post A.D. 360 pottery and the location of the coin hoard at the interface between occupation surface and collapse horizon indicate that this event cannot have occurred long after A.D. 360. We have interpreted this earthquake to be the historically attested earthquake of May 19, A.D. 363 (Russell 1980; Guidoboni 1994: 264-67).
Powers (2010) reports the following:
At the end of thetroubled third century, the Legio X Fretensis was transferred from Jerusalem to bolster Diocletian’s new Limes Arabicus, to the effect that the population increased substantially and the city emerged as a regional centre.61 A church was built in c. 300 – one of the oldest in the world – testifying to the early progress of Christianity in Palestine; it was apparently destroyed by the earthquake of 363 and subsequently covered by the new city wall. This stone and mud-brick wall was complete by the late fourth or early fifth century, suggesting something of the seriousness which the continued threat of Saracen raiding was taken.62

Footnotes

61 Parker, 1996: 234, 253; 2000: 392. Eusebius, Onomasticon, 6.17-21 (1904).
62 Parker, 2003: 332.

Earthquake VI - 1st half of 4th century CE

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Thomas et al (2007) identified earthquake destruction (Earthquake VI) in a collapse layer which they dated to the 4th century but before the southern Cyril Quake of 363 CE. In describing the Phase 2 layer below the collapse layer they provided a terminus post quem of ca. 320 CE
During the early fourth century, the monumental building was expanded and concluded with the final addition of Rooms 11 and 12 constructed after ca. A.D. 320. The upper sequences of floors contained Early Byzantine pottery of the mid to late fourth century.
The terminus ante quem is 363 CE when the southern Cyril Quake is presumed to have created the damage observed in Earthquake V.
This seismic event must have occurred at some point in the mid to late fourth century A.D. but before the final extensive collapse of the complex in Earthquake V [363 CE].

Earthquake VII - Nabatean/Early Roman - Early 2nd century CE

Stratigraphic Section

  • Composite columnar stratigraphic section for the deposits of the J-east site from Thomas et al (2007)
Earthquake VII was dated to the second century CE from Nabatean pottery found in the collapse layer and the layer below. There is a question whether the collapse layer was caused by human agency or earthquake destruction. The Romans annexed Nabatea in 106 CE and the authors noted that there is debate about the degree of Nabataean resistance to the annexation that might have resulted in destruction by human agency in this period (Bowersock 1983: 78-82; Parker 1986: 123-24; Fiema 1987; Freeman 1996). Nonetheless, Thomas et al (2007) noted that a complete section of collapsed wall might suggest earthquake destruction.

Seismic Effects
Earthquake I - after mid to late 8th century CE

Maps and Plans

  • Plan of Area J-east from Thomas et al (2007)
Sections
  • Figure 5C from Thomas et al (2007)
Thomas et al (2007) described archeoseismic evidence in Area J-east as follows:
The youngest earthquake (Earthquake I) recorded at this site ruptured faults very close to the modern ground surface.
...
Earthquake I ruptured Faults F and H. We measured a total displacement of 35 cm southwest dip-slip in figure 5C, with little or no apparent strike-slip. These faults trend more toward the west (N12°W and N34°W) than the fault rupture in previous earthquakes (ca. 10° more than II to III, and ca. 20° more than the Byzantine Earthquakes V to VI).

Earthquake II - Abbasid - after mid to late 8th century CE

Maps and Plans

  • Plan of Area J-east from Thomas et al (2007)
Sections
  • Figure 5C from Thomas et al (2007)
Thomas et al (2007) described archeoseismic evidence in Area J-east as follows:
These deposits were ruptured and the buildings collapsed. Slip on Fault A produced a left-lateral strike-slip of 5 cm on Wall J.1:26, and Faults A and E caused an accumulated southwest dip-slip of 42 cm (measured in fig. 5C). Wall collapse was minor despite the obvious energy of the earthquake.

Earthquake III - Umayyad/Abassid - mid 7th - late 8th century CE

Maps and Plans

  • Plan of Area J-east from Thomas et al (2007)
Sections
  • Figure 5C from Thomas et al (2007)
Thomas et al (2007) described archeoseismic evidence in Area J-east as follows:
This major event shows rupture along four fault strands (B, C, F, and G), all within the same fault corridor. Faults G and F were clearly visible cutting post monumental building tumble in the [Roman Aqaba Project] RAP 2002 excavations of J.29 in Room 13.
Fault B caused left-lateral slip on Wall J.1:26 of only 4 cm . However, the dip-slip for all four faults measured in Section 3 was 54 cm, suggesting a major event.
Earthquake III can also be seen in Section C of the south baulk of J-1 in Figure 5 (Faults B, C, F and G).

Earthquake IV - Umayyad - 7th - 8th centuries CE

Maps and Plans

  • Plan of Area J-east from Thomas et al (2007)
Sections
  • Figure 5C from Thomas et al (2007)
Thomas et al (2007) described archeoseismic evidence in Area J-east as follows:
Measured in Section C (fig. 5), Earthquake IV caused 12 cm of dip-slip across Fault D and up to 30 cm of lateral motion on Wall J.1.53. However, since Fault D also slipped in Earthquakes V and VI and appears to have caused more severe structural damage, strike-slip is probably minimal in this event.
...
Earthquake IV probably caused the collapse of the long-abandoned domestic structures.

Earthquake V - Early Byzantine - 363 CE

Maps and Plans

  • Plan of Area J-east from Thomas et al (2007)
Sections
  • Figure 4 from Thomas et al (2007)
  • Figure 5 - Sections A and B from Thomas et al (2007)
Thomas et al (2007) described seismic effects from Earthquake V in J-East as follows:
The monumental building appears to have been violently shaken in Earthquake V. This is a more severe reactivation of Faults C and D but occurs along a slightly different rupture plane (through the Room 20 north wall - see Fig. 4) than during EQ VI. The amount of fault slip in this earthquake must exceed 23 cm of dip-slip (measured in sections A and B, fig. 5). Where Fault D shifted Wall J.1:53, a maximum of 30 cm of left-lateral strike-slip was measured. This slip is shared by reactivation in Earthquake IV and the previous Earthquake VI (discussed above). The collapse layer for Earthquake V exceeds 90 cm in places. The tumble is more evenly distributed throughout the site than was the case for the earlier Earthquake VI, with a bias to the north side of collapsing walls. This thick collapse horizon across the site suggests Earthquake V was stronger in intensity compared with Earthquake VI. The majority of the lateral slip across Fault D is likely to have occurred predominantly in Earthquake V (but also moves in Earthquakes VI and IV).

Earthquake VI - 1st half of 4th century CE

Maps and Plans

  • Plan of Area J-east from Thomas et al (2007)
Thomas et al (2007) described seismic effects from Earthquake VI in J-East as follows:
The monumental mudbrick structure experienced fault rupture and collapse of some walls, producing a tumble horizon. The southern wall of Room 13 was ruptured by Fault D and the northern wall of Room 21 by Fault C. This tectonic shift caused substantial localized damage. Earthquake VI produced a total of 10 cm of left-lateral strike-slip measured across Fault C on Wall J.1:26, north of Room 21. This damage from the fault was repaired after Earthquake VI. The strike-slip of Fault D in EQ VI could not be measured because Fault D reactivated in subsequent Earthquakes V and IV. The total strike-slip measured along Wall J.1:53 is 30 cm. Since there was no repair to the wall, this suggests that the majority of the slip was caused by EQ VI. Similarly, the dip-slip could not be directly measured, but later releveling of the southwest corner of the monumental building indicates subsidence did occur. Elsewhere on the site, damage appears not to have been quite as severe, but seismically induced wall failures were repaired in the subsequent occupation phase.

Earthquake VII - Nabatean/Early Roman - Early 2nd century CE

Maps and Plans

  • Plan of Area J-east from Thomas et al (2007)
  • Map showing Area B from Dolinka (2003:32)
Thomas et al (2007) described seismic effects of Earthquake VII as follows:
These occupation deposits [Phase 0] were subsequently covered by a very thick layer of mudbrick collapse which contained whole or partial bricks visible in the section. The collapse dents the surfaces beneath, indicating a violent fall of the structures. Excavated in the RAP 2002 season, these layers were found to be in excess of 1 m in thickness.
...
No rupture for this possible earthquake (EQ VII) was documented in the present study because of the limited areas excavated to this depth (about 2 mast). Furthermore, subsequent building and reuse of the surviving walls have appreciably masked the original geometry.
At another site in Aila (Area B), Dolinka (2003:32) found that some structures exhibited inwardly collapsed walls and/or tumbled-over mudbricks
(Fig. 14 )
which was attributed to earthquake destruction. 89

Intensity Estimates
Earthquake I - after mid to late 8th century CE

Effect Description Intensity
Fault Scarps 35 cm southwest dip-slip VII +
Seismic Uplift/Subsidence 35 cm southwest dip-slip VI +
The archeoseismic evidence requires a minimum Intensity of VII (7) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224). However as so many structures at the now long abandoned site had already collapsed, there is limited archaeoseismic evidence and this is likely an under estimate. A minimum Intensity of VIII (8) is more likely. On-site fault rupture suggests a minimum moment magnitude MW of 6.5 (Mcalpin, 2009:312) and dip slip movement averaging 35 cm. also suggests a Moment Magnitude MW of 6.5 (see Calculators).

Earthquake II - Abbasid - after mid to late 8th century CE

Effect Description Intensity
Fault Scarps Faults A and E caused an accumulated southwest dip-slip of 42 cm. VII +
Displaced Walls Faults A and E caused an accumulated southwest dip-slip of 42 cm. VII +
Minor Wall Collapse VIII +
Seismic Uplift/Subsidence Faults A and E caused an accumulated southwest dip-slip of 42 cm. VI +
The archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224). On-site fault rupture suggests a minimum moment magnitude MW of 6.5 (Mcalpin, 2009:312) while dip slip movement averaging 42 cm. suggests a Moment Magnitude MW of 6.5 (see Calculator below). Strike-Slip movement of 5 cm. suggests a lower Moment Magnitude MW of 5.9 however given the obvious energy of the earthquake described by Thomas et al (2007), the 42 cm. of dip slip and the general rule of Mcalpin (2009:312), Moment Magnitude MW is likely at least 6.5. The limited strike-slip and significant dip slip may just suggests a different stress regime.

Earthquake III - Umayyad/Abassid - mid 7th - late 8th century CE

Effect Description Intensity
Fault Scarps dip-slip for all four faults measured in Section 3 was 54 cm. VII +
Displaced Walls dip-slip for all four faults measured in Section 3 was 54 cm.
Figure 4 Walls J.1.26 Fault C and J.1.48 Fault F
VII +
Seismic Uplift/Subsidence dip-slip for all four faults measured in Section 3 was 54 cm. VI +
Conjugate Fractures in walls
made of either stucco or bricks
Figure 4 Wall J.1.26 Fault C
V +
The archeoseismic evidence requires a minimum Intensity of VII (7) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224). However, since Thomas et al (2007) describe this as a major event and dip slip is 54 cm., I am going to upgrade minimum Intensity to VIII (8). On-site fault rupture suggests a minimum moment magnitude MW of 6.5 (Mcalpin, 2009:312) while dip slip movement averaging 54 cm. suggests a Moment Magnitude MW of 6.6 (see Calculators).

Earthquake IV - Umayyad - 7th - 8th centuries CE

Effect Description Intensity
Fault Scarps dip-slip VII +
Displaced Walls VII +
Collapsed Walls VIII +
Seismic Uplift/Subsidence VI +
The archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224). however since the site was abandoned at the time, the walls may have been weakened. Since Thomas et al (2007) estimated that earthquakes V (S. Cyril Quake) and VI (Aila Quake) were more energetic at the site and an Intensity of VIII (8) was estimated for these earthquakes, it seems prudent to downgrade the intensity estimate one count to VII (7). On-site fault rupture suggests a minimum moment magnitude MW of 6.5 (Mcalpin, 2009:312). 12 cm. of dip-slip movement suggests a Moment Magnitude Mw between 6.0 and 6.2. 10 cm. of strike-slip movement also suggests a Moment Magnitude Mw between 6.0 and 6.2. while the upper limit of 30 cm. of strike-slip movement suggests a maximum Moment Magnitude Mw between 6.4 and 6.6 (see Calculators).

Earthquake V - Early Byzantine - 363 CE

Effect Description Intensity
Fault Scarps dip-slip VII +
Tilted Walls VI +
Displaced Walls VII +
Collapsed Walls VIII +
Seismic Uplift/Subsidence VI +
The archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224). On-site fault rupture suggests a minimum moment magnitude MW of 6.5 (Mcalpin, 2009:312) while dip slip movement greater than 23 cm. suggests a minimum Moment Magnitude MW of 6.4 and maximum strike-slip movement of 30 cm. suggests a Moment Magnitude MW of 6.4 (see Calculators).

Earthquake VI - 1st half of 4th century CE

Effect Description Intensity
Fault Scarps dip-slip VII +
Displaced Walls VII +
Collapsed Walls VIII +
Seismic Uplift/Subsidence VI +
The archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224). On-site fault rupture suggests a minimum moment magnitude MW of 6.5 (Mcalpin, 2009:312). 10-30 cm. of strike-slip movement suggests a Moment Magnitude Mw between 6.0 and 6.6 (see Calculators).

Earthquake VII - Nabatean/Early Roman - Early 2nd century CE

Effect Description Intensity
Impact Block Marks Area J-east V +
Collapsed Walls Complete section of collapsed wall in Area J-east
Inwardly collapsed walls and/or tumbled-over mudbricks in Area B
VIII +
The archeoseismic evidence requires a minimum Intensity of VIII (8) when using the Earthquake Archeological Effects chart of Rodríguez-Pascua et al (2013: 221-224).

Calculators
Normal Fault Displacement

Source - Wells and Coppersmith (1994)

Variable Input Units Notes
cm.
cm.
m/s Enter a value of 655 for no site effect
Equation comes from Darvasi and Agnon (2019)
Variable Output - not considering a Site Effect Units Notes
unitless Moment Magnitude for Avg. Displacement
unitless Moment Magnitude for Max. Displacement
Variable Output - Site Effect Removal Units Notes
unitless Reduce Intensity Estimate by this amount
to get a pre-amplification value of Intensity
  

Strike-Slip Fault Displacement

Source - Wells and Coppersmith (1994)

Variable Input Units Notes
cm. Strike-Slip displacement
cm. Strike-Slip displacement
Variable Output - not considering a Site Effect Units Notes
unitless Moment Magnitude for Avg. Displacement
unitless Moment Magnitude for Max. Displacement
  

Site Effect Explanation

The value given for Intensity with site effect removed is how much you should subtract from your Intensity estimate to obtain a pre-amplification value for Intensity. For example if the output is 0.5 and you estimated an Intensity of 8, your pre-amplification Intensity is now 7.5. An Intensity estimate with the site effect removed is helpful in producing an Intensity Map that will do a better job of "triangulating" the epicentral area. If you enter a VS30 greater than 655 m/s you will get a positive number, indicating that the site amplifies seismic energy. If you enter a VS30 less than 655 m/s you will get a negative number, indicating that the site attenuates seismic energy rather than amplifying it. Intensity Reduction (Ireduction) is calculated based on Equation 6 from Darvasi and Agnon (2019).

VS30 Explanation

VS30 is the average seismic shear-wave velocity from the surface to a depth of 30 meters at earthquake frequencies (below ~5 Hz.). Darvasi and Agnon (2019) estimated VS30 for a number of sites in Israel. If you get VS30 from a well log, you will need to correct for intrinsic dispersion. There is a seperate geometric dispersion correction usually applied when processing the waveforms however geometric dispersion corrections are typically applied to a borehole Flexural mode generated from a Dipole source and for Dipole sources propagating in the first 30 meters of soft sediments, modal composition is typically dominated by the Stoneley wave. Shear from Stoneley estimates are approximate at best. This is a subject not well understood and widely ignored by the Geotechnical community and/or Civil Engineers but understood by a few specialists in borehole acoustics. Other considerations will apply if you get VS30 value from a cross well survey or a shallow seismic survey where the primary consideration is converting shear slowness from survey frequency to Earthquake frequency. There are also ways to estimate shear slowness from SPT & CPT tests.

Notes and Further Reading
References

Articles and Books

Thomas, et al. (2007). "Structural damage from earthquakes in the second-ninth centuries at the archaeological site of Aila in Aqaba, Jordan: PERA." Bull Am Sch Orient Res 346: 59-77.

Niemi, T. M. (2014). Chapter 2. The Regional Environment: in The Roman Aqaba Project Final Report volume 1: The Regional Environment and the Regional Survey Archaeological Reports 19. S. T. Parker et al, III (eds). Boston, MA, American School of Oriental Research. 1: 33-80.

Dolinka, B. J. (2003). Nabataean Aila (Aqaba, Jordan) from a Ceramic Perspective Local and intra-regional trade in Aqaba Ware during the first and second centuries AD. Evidence from the Roman Aqaba Project.

Power, T. (2010). The Red Sea during the 'Long' Late Antiquity, AD 500-1000. Faculty of Oriental Studies. Oxford, University of Oxford. PhD.: 578.

Parker, S.T. 1986. Romans and Saracens: A History of the Arabian Frontier. Winona Lake.

Parker, S.T. 1987a. Peasants, Pastoralists and Pax Romana: A Different View. Bulletin of the American Schools of Oriental Research 265: 35-51.

Parker, S.T. 1996. The Roman ʿAqaba Project: the 1994 Campaign. Annual of the Department of Antiquities of Jordan 40: 231-57.

Parker, S.T. 1997. Preliminary Report on the 1994 Season of the Roman Aqaba Project. Bulletin of the American Schools of Oriental Research 305: 19-44.Parker, S.T. 1998. The Roman ʿAqaba Project: the 1996 Campaign. Annual of the Department of Antiquities of Jordan 42: 375-94.

Parker, S.T. 1999. Brief Notice on a possible Fourth-Century Church at Aqaba, Jordan. Journal of Roman Archaeology 12: 372–376.

Parker, S.T. 2000. The Roman ʿAqaba Project: the 1997 and 1998 Campaigns. Annual of the Department of Antiquities of Jordan 44: 373-94.

Parker, S.T. 2002. The Roman ʿAqaba Project: the 2000 Campaign. Annual of the Department of Antiquities of Jordan 46: 409-28.

Parker, S.T. 2003. The Roman ʿAqaba Project: the 2002 Campaign. Annual of the Department of Antiquities of Jordan 47: 321-33.

Parker, S.T. 2006. Roman Aila and the Wadi Arabah: An Economic Relationship. In P. Bienkowski & K. Galor (eds.) Crossing the Rift. Resources, Routes, Settlement Patterns and Interaction in the Wadi Arabah. Oxford. pp. 223-230.

Parker, S.T. 2009. The Roman Port of Aila: Economic Connections with the Red Sea Littoral. In L. Blue, J. Cooper, R. Thomas & J. Whitewright (eds.) Connected Hinterlands. Proceedings of the Red Sea Project IV. Held at the University of Southampton, September 2008. Oxford. pp. 79-84



Excavation Reports

Parker, S.T. 1987b. History of the Roman Frontier East of the Dead Sea. In T.S. Parker (ed.) The Roman Frontier in Central Jordan: Interim Report on the Limes Arabicus Project, 1980-1985. 2 Vols. Oxford. pp. 793-823.



Websites

Aila Port (Ayla) (Aqaba) at Nabataea.net