Ayla

Introduction

Around 650 CE, a new Islamic city was established outside the walls of the old Byzantine town. The new town was known as Ayla. Located near the coastline of the modern city of Aqaba, Ayla was excavated starting in 1993 ( S. Thomas Parker and Donald S. Whitcomb in Meyers et al, 1997). Ayla is likely subject to a site effect due to it susceptibility to liquefaction.

Aqaba/Elat - Introduction Webpage

from Aqaba/Elat - Introduction - click link to open new tab

Maps, Aerial Views, Plans, and Photos

Maps

Normal Size

Fig. 2.15 - Location Map

Figure 2.15

Map of archaeological sites in greater Aqaba, Jordan region (modified after Brückner et al. 2002).

Allison (2013)

for Aqaba and environs from Allison (2013)
Map showing location

Map of the modern city of Aqaba with ancient and medieval archeological sites

JW: Apparently Ailana = Aila

Whitcomb (1988)

of Islamic Ayla and Byzantine Aila (aka Ailana) from Whitcomb (1988)
Fig. 2 Map showing

Figure 2

The succession of settlements at 'Aqaba, Jordan

Whitcomb (1997)

location of Islamic Ayla and Byzantine Aila from Whitcomb (1997)

Magnified

Fig. 2.15 - Location Map

Figure 2.15

Map of archaeological sites in greater Aqaba, Jordan region (modified after Brückner et al. 2002).

Allison (2013)

for Aqaba and environs from Allison (2013)

Aerial Views

Ayla in Google Earth

Ayla

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Plans

Normal size

Fig. 2 Plan of Islamic

Figure 2

Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993)

al-Tarazi and Khorjenkov (2007)

Ayla from al-Tarazi and Khorjenkov (2007)
Fig. 1 Site Plan with Excavation

Figure 1

Phased plan of the archaeological site of Aylah. The new excavations are in the southwest quadrant

(© AAP)

Damgaard and Jennings (2013)

Areas of the Aqaba Archaeological Project from Damgaard and Jennings (2013)
Fig. 2 Plan of Area IM

Figure 2

Phased plan of excavation area in the southwest quadrant of Aylah

(© AAP)

Damgaard and Jennings (2013)

of the Aqaba Archaeological Project from Damgaard and Jennings (2013)

Magnified

Fig. 2 Plan of Islamic

Figure 2

Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993)

al-Tarazi and Khorjenkov (2007)

Ayla from al-Tarazi and Khorjenkov (2007)
Fig. 1 Site Plan with Excavation

Figure 1

Phased plan of the archaeological site of Aylah. The new excavations are in the southwest quadrant

(© AAP)

Damgaard and Jennings (2013)

Areas of the Aqaba Archaeological Project from Damgaard and Jennings (2013)
Fig. 2 Plan of Area IM

Figure 2

Phased plan of excavation area in the southwest quadrant of Aylah

(© AAP)

Damgaard and Jennings (2013)

of the Aqaba Archaeological Project from Damgaard and Jennings (2013)

Photos

Normal Size

Fig. 5 - Photo of tilted

Fig. 5

Section of the Sea Wall [in Islamic Ayla], tilted outward and buttressed in antiquity, with reconstructed wall on original alignment in background, view to SE. from Whitcomb (1995)

Niemi (2009)

Sea Wall in Islamic Ayla from Niemi (2009)
Fig. 4 - Displaced Wall

Fig. 4

Map of Ayla according to Whitcomb(1994) (modifed). The western side of the town is affected by sinistral wrenching that displaces the southern wall and forces the northwestern wall to rotate counterclockwise (see inset photo).

JW: Rucker and Niemi (2005) trenched the site and found no evidence of this fault suggesting that the wall displacement shown is due to seismic forces perhaps aided by liquefaction.

Galli and Galadini (2001)

from Galli and Galadini (2001)

Magnified

Fig. 5 - Photo of tilted

Fig. 5

Section of the Sea Wall [in Islamic Ayla], tilted outward and buttressed in antiquity, with reconstructed wall on original alignment in background, view to SE. from Whitcomb (1995)

Niemi (2009)

Sea Wall in Islamic Ayla from Niemi (2009)
Fig. 4 - Displaced Wall

Fig. 4

Map of Ayla according to Whitcomb(1994) (modifed). The western side of the town is affected by sinistral wrenching that displaces the southern wall and forces the northwestern wall to rotate counterclockwise (see inset photo).

JW: Rucker and Niemi (2005) trenched the site and found no evidence of this fault suggesting that the wall displacement shown is due to seismic forces perhaps aided by liquefaction.

Galli and Galadini (2001)

from Galli and Galadini (2001)

Phasing

Whitcomb (1994) divided up the stratigraphy of Ayla into 5 phases as did Damgaard (2011) and Damgaard (2013). Damgaard (2011) and Damgaard (2013)'s phasing are accessible on tabs in the spreadsheet below.

First Earthquake - 7th - 8th centuries CE

Plans and Photos

Plans

Normal size

Fig. 2 Plan of Islamic

Figure 2

Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993)

al-Tarazi and Khorjenkov (2007)

Ayla from al-Tarazi and Khorjenkov (2007)

Magnified

Fig. 2 Plan of Islamic

Figure 2

Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993)

al-Tarazi and Khorjenkov (2007)

Ayla from al-Tarazi and Khorjenkov (2007)

Photos

Fig. 9 Negative profile

Figure 9

Negative of the early Abbasid wall (L77)

Damgaard (2008)

('Robber Trench') from Damgaard (2008)
Fig. 10 Mud-brick collapse

Figure 10

Associated mud-brick collapse (L86)

Damgaard (2008)

from Damgaard (2008)

Discussion

The first earthquake was revealed in the constructions built during the late Rashidun period (644-656 A.D.) ( al-Tarazi and Khorjenkov, 2007) thus providing a terminus post quem of 644-656 A.D.. A terminus ante quem of ~750 CE was provided by the Early Abbasid structures built after the first seismic destruction. This suggests that the seismic damage was caused by the Jordan Valley Quake of 659/660 CE (less likely due to distance) or one of the mid 8th century CE earthquakes.

In reporting on excavations in 2008, Damgaard (2008) observed substantial infilling and leveling in Phase 3 which based on its artefactual yield, must be considered Abbasid in date and corresponds roughly to Whitcomb's `Phase B'. Damgaard (2008) suggested that this levelling appears to be associated with a period of widespread reconstruction following a significant collapse - most probably due to the 748 CE earthquake. Of particular interest was an east-west running wall perpendicular to a north-south running wall (L57/W13). Only the negative profile of this wall remains - i.e. it is a robber trench (Fig. 9). Although nothing of its foundation remains, the fact that the remnants of a wall [are] now gone was confirmed by a patterned collapse of mud-brick (including a carbonised wooden beam) on its south side. (Fig 10). Damgaard (2011, Appendices:12) also reports a collapse layer in Tower 2 dated to the mid 8th century. Thus, it appears that the terminus ante quem is fairly reliable for this archeoseismic evidence and suggests a mid 8th century CE earthquake. Khouri and Whitcomb (1988) report that the earlier Abbasid houses were fine stone and brick residences.

Second Earthquake - 1068 CE

Plans

Normal size

Fig. 2 Plan of Islamic

Figure 2

Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993)

al-Tarazi and Khorjenkov (2007)

Ayla from al-Tarazi and Khorjenkov (2007)

Magnified

Fig. 2 Plan of Islamic

Figure 2

Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993)

al-Tarazi and Khorjenkov (2007)

Ayla from al-Tarazi and Khorjenkov (2007)

Discussion

The second earthquake was revealed in structures restored and/or built during the Fatimid period (1050-1116 A.D.) ( al-Tarazi and Khorjenkov, 2007) thus providing a terminus post quem of 1050-1116 AD. A number of authors report that Ayla was damaged during the 1068 CE Quake(s). Abu Ali ibn al-Banna and Sibt Ibn al-Jawzi reports that in Ayla all but 12 people who had gone fishing survived. al-Tarazi and Khorjenkov (2007) note that Donald Whitcomb discovered a destruction layer associated with this earthquake which he presumes led to abandonment of the village due to its destruction.

Archaeoseismic Survey in Ayla

al-Tarazi and Khorjenkov (2007) undertook an archaeoseismic investigation in Ayla and saw evidence for two different earthquakes. The first earthquake struck in the 7th or 8th centuries CE and the second struck in 1068 CE. Their work was done at a restored site initially excavated by Donald Whitcomb.

First Earthquake - 7th - 8th centuries CE

Evidence type	Station	Location	Figure	Comments
Wall Repairs	3	near N corner of Ayla City Wall Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	8 Figure 8 Traces of poor quality repair in Ayla city wall to the NE from the city tower no. 4 (station no. 3) al-Tarazi and Khorjenkov (2007)	poor quality repairs of the Ayla city wall - al-Tarazi and Khorjenkov (2007)
Wall Repairs	6	City quarter D Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	9 Figure 9 Mismatch of lower row of stones and upper wall fragments in city quarter D (station no. 6). There is a difference of 9° between the trends of two walls al-Tarazi and Khorjenkov (2007)	clear mismatch between the lower row of stones and the upper wall fragment. The height of the lower row is 40 cm above the bottom of the excavated trench, where the height of the upper wall fragment is 160 cm. The azimuth of the lower row is 34°, while that of the upper wall fragment is 25° showing a difference of 9°. - al-Tarazi and Khorjenkov (2007)
Supporting Walls	7	City Quarter D Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	10 Figure 10 A wall perpendicular to the city wall (city Quarter D; station no. 7) has a supporting wall from its NE side. The last wall was built later in order to strengthen the original one that was tilted toward NE al-Tarazi and Khorjenkov (2007)	Wall perpendicular to the city wall has a supporting wall on its NE side. The latter wall was built later in order to strengthen the original one that was tilted toward the NE. The height of the original wall is 300 cm above the bottom of the excavation trench has a declination azimuth of 41° and a tilt angle of 83°. - al-Tarazi and Khorjenkov (2007)
Supporting Walls	21	W corner of city wall Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	4b Figure 4b Tilted walls in Ayla towards the SSW: (b) In seashore area (Station 21). Note the tilting of both the lower fragment of a column and a later built supporting wall. al-Tarazi and Khorjenkov (2007)	short secondary wall was built in order to support (apparently) a deformed column. Deformation of the column possibly occurred during the 748 Umayyad earthquake. Subsequently, both column and supporting wall were tilted toward SSW during the second-Fatimid earthquake of 1068. - al-Tarazi and Khorjenkov (2007) Tens of supporting walls were observed in the ruins of Ayla, suggesting the hypothesis that during the first Umayyad period earthquake the city was seriously damaged. Building elements were tilted, shifted, distorted, and special supporting walls were subsequently built in order to reinforce damaged constructions. - al-Tarazi and Khorjenkov (2007)
Secondary use of building materials in Early Abbasid buildings	7	City quarter D Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	11a Figure 11a Secondary use of building stones in Ayla. (a) A column drum built into the street wall in city quarter D (station no. 7). al-Tarazi and Khorjenkov (2007)	column drum which is now inside of the street wall - al-Tarazi and Khorjenkov (2007)
Secondary use of building materials in Early Abbasid buildings	13	City quarter F Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	11b Figure 11b Secondary use of building stones in Ayla. Two column drums at city quarter F (station no. 13): the right one belonged to the lower part of the column. It was probably damaged during the Umayyad earthquake. The left column drum was used later in order to support and reinforce the damaged column al-Tarazi and Khorjenkov (2007)	two column drums belonging to a column likely damaged during the Umayyad earthquake. Another column drum (left in Fig. 11b) was later used in order to support the damaged column, while during the Fatimid earthquake, the column was finally destroyed and both drums were shifted out from their previous position. - al-Tarazi and Khorjenkov (2007)
Collapsed Walls	n/a	an east-west running wall perpendicular to a north-south running wall (L57/W13) in Area IM as defined by Damgaard (2008) Figure 1 Phased plan of the archaeological site of Aylah. The new excavations are in the southwest quadrant (© AAP) Damgaard and Jennings (2013) Figure 2 Phased plan of excavation area in the southwest quadrant of Aylah (© AAP) Damgaard and Jennings (2013)	Figure 9 Negative [aka Robber Trench] of the early Abbasid wall (L77) Damgaard (2008) Figure 10 Associated mud-brick collapse (L86) Damgaard (2008)	the remnants of a wall [are] now gone [robber trench in Fig. 9] was confirmed by a patterned collapse of mud-brick (including a carbonised wooden beam) on its south side [Fig. 10] - Damgaard (2008)

Second Earthquake - 1068 CE

Evidence type	Station	Plan	Figure	Comments
Systematic tilting of walls	20 21	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	4a Figure 4a Tilted walls in Ayla towards the SSW (a) In a room of the Sea Gate building complex (Station 20) al-Tarazi and Khorjenkov (2007) 4b Figure 4b Tilted walls in Ayla towards the SSW (b) In seashore area (Station 21). Note the tilting of both the lower fragment of a column and a later built supporting wall. al-Tarazi and Khorjenkov (2007) 4c Figure 4c Tilted walls in Ayla towards the SSW (c) Summary of measurements: direction of tilting patterns observed in Ayla as a function of the direction of the walls. ESE trending walls have systematic tilt toward SSW. al-Tarazi and Khorjenkov (2007) 4d Figure 4d Tilted walls in Ayla towards the SSW (d) Qualitative model showing the types of propagation of the seismic motions during the Nuweiba 1995 earthquake. Ayla was in the compression quadrangle and most of the walls oriented SE were tilted towards SW due to inertia al-Tarazi and Khorjenkov (2007)	At Ayla, a wall in the southern room of the Sea Gate building complex K (Station 20 in Fig. 2 - Plan) is tilted toward SSW at an angle of up to 66° (in its central part) with a declination azimuth of 213° (Fig. 4a). Another example of the same damage pattern is in station 21 (in the western corner of the city wall), where a fragment of the wall is tilted at an angle of 72° with a declination angle of 210° (Fig. 4b). The data of surveyed cases of tilting are summarized in Table 2 and in Fig. 4c. A 24 cases of tilting were observed at walls trending between 105° and 145°, 19 out of these are tilted toward SW and only 5 are tilted towards NE (Fig. 4c). In contrast, only 11 cases of tilting were observed in the perpendicular walls, with a 10°-45° trend, and no systematic tilting was observed. - al-Tarazi and Khorjenkov (2007)
Lateral shifting of building elements	1	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	5a Figure 5a Shifting of wall fragments in Ayla: (a) Shift toward the SSW of the upper part of a wall attached and perpendicular to the city wall (station no. 1). al-Tarazi and Khorjenkov (2007) 5b Figure 5b Shifting of wall fragments in Ayla: (b) Summary of measurements: direction of shifting patterns observed in Ayla as a function of the direction of the walls. ESE trending walls have systematic shift toward SSW. al-Tarazi and Khorjenkov (2007) 5c Figure 5c Shifting of wall fragments in Ayla: (c) photograph and al-Tarazi and Khorjenkov (2007) 5d Figure 5d Shifting of wall fragments in Ayla: ( d) scheme. Shift toward the epicenter of the upper part of the grave monument during Suusamyr (1992, Ms = 7.3) earthquake in Kyrgyzstan al-Tarazi and Khorjenkov (2007)	In Ayla, a 75 cm wide wall attached and perpendicular to a major city wall (station no. 1 — close to the northern corner of the city wall) has an original trend of 120°. Its upper part is shifted towards SSW (210°) of about 16 cm (Fig. 5a). The lower and undisturbed portion of the wall is 44 cm above the bottom of the excavation trench. The height of the preserved shifted fragment is 18 cm. The wall is composed of cemented sandstone and granite blocks. The upper part of the highly deformed wall attached and perpendicular to the city wall (Station 3 in city Quarter E) was shifted 7 cm toward SSW. The wall trend is 115°, while the direction of shifting is 205°. Total height of the wall is 81 cm above the bottom of the excavation trench. At a later stage, a supporting wall of 84 cm width was built from the southern side in order to impede the collapse from the original wall. Other seven cases of clear shifting were observed (Fig. 5b). Most of them are in walls trending 105°-120°. Three wall fragments were pushed toward the SSW and in one case the wall part was moved towards the opposite direction. - al-Tarazi and Khorjenkov (2007)
Rotation of wall fragments around a vertical axis	2 10 or 12	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	6a Figure 6a Rotations of the wall fragments in Ayla. (a) A counterclockwise rotation in the northwestern wall of the 4th city tower. The arrows point to a through-going joint (station no. 2). al-Tarazi and Khorjenkov (2007) 6b Figure 6b Rotations of the wall fragments in Ayla. (b) Ayla city complex A: Upper part of the wall was rotated clockwise by 15° (station no. 10). al-Tarazi and Khorjenkov (2007) 6c Figure 6c Rotations of the wall fragments in Ayla. (c) Angle of rotation as a function of the wall trend: mostly counterclockwise rotations were observed in NNE walls and more clockwise rotations in ESE walls al-Tarazi and Khorjenkov (2007)	In Ayla, there is a rotation pattern in the northwestern wall of the 4th city tower (station no. 2). The height of the remaining wall is 139 cm above the bottom of the excavation trench. The trend of the undisturbed wall is 124°, while the strike of the rotated wall fragment is 115°, this suggesting a counterclockwise rotation on 9° with maximum degree of rotation for the lower row of the wall (Fig. 6a). The maximum horizontal offset between two wall fragments is 8 cm. Another example is at station no. 12 (Ayla's city quarter A), where the upper part of the wall was rotated 15° clockwise by (Fig. 6b). The strike of the undisturbed wall is 117° and the strike of the rotated wall is 132°. The height of the undisturbed wall fragment is 40 cm, while the rotated part is 60 cm high. Width of the wall is 40-50 cm; its length is 2 m. Walls striking 20°-45° revealed six cases of rotation and out of them five are counterclockwise and only one is clockwise (Fig. 6c). The perpendicular walls, trending 115°-130° revealed five cases of rotation, out of which two cases are counterclockwise and three cases are clockwise. Thus, a systematic picture of rotations is obtained: counterclockwise in NNE trending walls and clockwise in ESE walls (Fig. 6c). - al-Tarazi and Khorjenkov (2007)
Fractures across walls	20 2	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	7 Figure 7 Tilted walls in Ayla towards the SSW (a) In a room of the Sea Gate building complex (Station 20) al-Tarazi and Khorjenkov (2007) 6a Figure 6a Rotations of the wall fragments in Ayla. (a) A counterclockwise rotation in the northwestern wall of the 4th city tower. The arrows point to a through-going joint (station no. 2). al-Tarazi and Khorjenkov (2007)	Long through fissures cutting a whole wall are common phenomena among earthquake damage patterns (Stiros 1996; Korjenkov and Lemzin 2000). Several such patterns were also observed in Ayla. For example, a secondary wall attached and perpendicular to the main city wall (Station 3 in city Quarter E) was cut by a joint. The 55 cm long joint (left one in Fig. 7) crosses two stones of a 121° trending wall. Another joint (Fig. 6a, shown by arrows) cutting through two adjacent stones which are located in the northwestern wall of the 4th city tower (station No. 2). The height of the wall is 139 cm above the bottom of the excavation trench. The trend of the wall fragment is 124°. The described damage pattern occurred during last strong 1995 earthquake (I = VDT, Al-Tarazi 2000), was strong enough to cause significant damage in weak remnants of ancient buildings, especially those already excavated. Local site effects like liquefaction and subsidence could have increased the damage level. - al-Tarazi and Khorjenkov (2007)

First Earthquake - 7th - 8th centuries CE

Modified by JW from Fig. 2 of al-Tarazi and Khorjenkov (2007) and Fig. 2 of Damgaard and Jennings (2013)

Deformation Map

Modified by JW from Fig. 2 of al-Tarazi and Khorjenkov (2007) and Fig. 2 of Damgaard and Jennings (2013)

Second Earthquake - 1068 CE

Modified by JW from Fig. 2 of al-Tarazi and Khorjenkov (2007)

Deformation Map

Modified by JW from Fig. 2 of al-Tarazi and Khorjenkov (2007)

First Earthquake - 7th - 8th centuries CE

from al-Tarazi and Khorjenkov (2007)

The percentage of collapsed buildings of the Rashidun town is hard to estimate as most of the buildings have been cleared away and rebuilt. Nevertheless, an estimate can be done because most of the second floors or upper parts of high structures were rebuilt at the Umayyad and Early Abbasid stage leading to the estimate that at least 15% of the buildings were destroyed by the earthquake occurred at the end of the Umayyad period. According to the EMS-98 an earthquake intensity of IX or more is inferred.

Second Earthquake - 1068 CE

from al-Tarazi and Khorjenkov (2007)

Figures

Fig. 4d Types of propagation

Figure 4d

Qualitative model showing the types of propagation of the seismic motions during the Nuweiba 1995 earthquake. Ayla was in the compression quadrangle and most of the walls oriented SE were tilted towards SW due to inertia

al-Tarazi and Khorjenkov (2007)

during the Nuweiba 1995 earthquake from al-Tarazi and Khorjenkov (2007)

Discussion

A clear preference of southwest tilting is observed at the ruins of Ayla. Accordingly, the seismic shock likely arrived from the SW (Fig. 4d). As it is known the DST is a sinistral strike-slip fault and Ayla is located on the eastern block that moves northwards during strong earthquakes. Therefore, the building constructions are tilted to opposite direction because of inertia (Fig. 4d).

... Based on the above description of shifted building elements, the seismic shocks arrived from the SSW and the movements were transmitted from the ground to the building foundations, causing the upper wall fragments to move in an opposite direction due to inertia.

... The analysis of the clockwise and anticlockwise rotations supports a likely NNE-SSW direction of the seismic motion.

... Through-going joints are likely formed as a result of high intensity earthquake, while high energy is necessary to overcome the stress shadow of free surfaces at the stone margins (i.e., the free space between adjacent stones).

... The percentage of collapsed buildings of the Fatimid town can be well estimated as the ruins were left untouched. The survey disclosed that at least 15% of the well-built stone buildings of Fatimid Ayla collapsed and in practice no second floor structures survived with no severe damage. Again an EMS-98 intensity of IX or more is assumed.

First Earthquake - 7th - 8th centuries CE

Intensity Estimate from the Earthquake Archaeological Effects (EAE) Chart

Earthquake Archeological Effects chart

Earthquake Archeological Effects (EAE)

Rodríguez-Pascua et al (2013: 221-224)

of Rodríguez-Pascua et al (2013: 221-224)

Evidence type	Station	Location	Figure	Comments	Intensity
Displaced Walls indicated by Wall Repairs	3	near N corner of Ayla City Wall Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	8 Figure 8 Traces of poor quality repair in Ayla city wall to the NE from the city tower no. 4 (station no. 3) al-Tarazi and Khorjenkov (2007)	poor quality repairs of the Ayla city wall - al-Tarazi and Khorjenkov (2007)	VII+
Displaced Walls indicated by Wall Repairs	6	City quarter D Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	9 Figure 9 Mismatch of lower row of stones and upper wall fragments in city quarter D (station no. 6). There is a difference of 9° between the trends of two walls al-Tarazi and Khorjenkov (2007)	clear mismatch between the lower row of stones and the upper wall fragment. The height of the lower row is 40 cm above the bottom of the excavated trench, where the height of the upper wall fragment is 160 cm. The azimuth of the lower row is 34°, while that of the upper wall fragment is 25° showing a difference of 9°. - al-Tarazi and Khorjenkov (2007)	VII+
Tilted Walls indicated by Supporting Walls	7	City Quarter D Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	10 Figure 10 A wall perpendicular to the city wall (city Quarter D; station no. 7) has a supporting wall from its NE side. The last wall was built later in order to strengthen the original one that was tilted toward NE al-Tarazi and Khorjenkov (2007)	Wall perpendicular to the city wall has a supporting wall on its NE side. The latter wall was built later in order to strengthen the original one that was tilted toward the NE. The height of the original wall is 300 cm above the bottom of the excavation trench has a declination azimuth of 41° and a tilt angle of 83°. - al-Tarazi and Khorjenkov (2007)	VI+
Tilted Walls indicated by Supporting Walls	21	W corner of city wall Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	4b Figure 4b Tilted walls in Ayla towards the SSW: (b) In seashore area (Station 21). Note the tilting of both the lower fragment of a column and a later built supporting wall. al-Tarazi and Khorjenkov (2007)	short secondary wall was built in order to support (apparently) a deformed column. Deformation of the column possibly occurred during the 748 Umayyad earthquake. Subsequently, both column and supporting wall were tilted toward SSW during the second-Fatimid earthquake of 1068. - al-Tarazi and Khorjenkov (2007) Tens of supporting walls were observed in the ruins of Ayla, suggesting the hypothesis that during the first Umayyad period earthquake the city was seriously damaged. Building elements were tilted, shifted, distorted, and special supporting walls were subsequently built in order to reinforce damaged constructions. - al-Tarazi and Khorjenkov (2007)	VI+
Broken columns indicated by Secondary use of building materials in Early Abbasid buildings	7	City quarter D Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	11a Figure 11a Secondary use of building stones in Ayla. (a) A column drum built into the street wall in city quarter D (station no. 7). al-Tarazi and Khorjenkov (2007)	column drum which is now inside of the street wall - al-Tarazi and Khorjenkov (2007)	VI or VII +
Broken columns indicated by Secondary use of building materials in Early Abbasid buildings	13	City quarter F Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	11b Figure 11b Secondary use of building stones in Ayla. Two column drums at city quarter F (station no. 13): the right one belonged to the lower part of the column. It was probably damaged during the Umayyad earthquake. The left column drum was used later in order to support and reinforce the damaged column al-Tarazi and Khorjenkov (2007)	two column drums belonging to a column likely damaged during the Umayyad earthquake. Another column drum (left in Fig. 11b) was later used in order to support the damaged column, while during the Fatimid earthquake, the column was finally destroyed and both drums were shifted out from their previous position. - al-Tarazi and Khorjenkov (2007)	VI or VII +
Collapsed Walls	n/a	an east-west running wall perpendicular to a north-south running wall (L57/W13) in Area IM as defined by Damgaard (2008) Figure 1 Phased plan of the archaeological site of Aylah. The new excavations are in the southwest quadrant (© AAP) Damgaard and Jennings (2013) Figure 2 Phased plan of excavation area in the southwest quadrant of Aylah (© AAP) Damgaard and Jennings (2013)	Figure 9 Negative [aka Robber Trench] of the early Abbasid wall (L77) Damgaard (2008) Figure 10 Associated mud-brick collapse (L86) Damgaard (2008)	the remnants of a wall [are] now gone [robber trench in Fig. 9] was confirmed by a patterned collapse of mud-brick (including a carbonised wooden beam) on its south side [Fig. 10] - Damgaard (2008)	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).

Seismic Parameters from al-Tarazi and Khorjenkov (2007)

al-Tarazi and Khorjenkov (2007) estimated an intensity of IX or more for the Umayyad period earthquake and surmised that the epicenter was close - a few tens of kilometers away. They estimated that the epicenter was to the NE.

Although based on limited observations the direction of tilt and resystematic block towards NE during Umayyad (748 A.D) and Fatimid (1086 A.D.) earthquakes are likely evidence of seismic motions radiated from the earthquake sources located NE of Ayla.

Second Earthquake - 1068 CE

Intensity Estimate from the Earthquake Archaeological Effects (EAE) Chart

Earthquake Archeological Effects chart

Earthquake Archeological Effects (EAE)

Rodríguez-Pascua et al (2013: 221-224)

of Rodríguez-Pascua et al (2013: 221-224)

Evidence type	Station	Plan	Figure	Comments	Intensity
Systematic tilting of walls	20 21	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	4a Figure 4a Tilted walls in Ayla towards the SSW (a) In a room of the Sea Gate building complex (Station 20) al-Tarazi and Khorjenkov (2007) 4b Figure 4b Tilted walls in Ayla towards the SSW (b) In seashore area (Station 21). Note the tilting of both the lower fragment of a column and a later built supporting wall. al-Tarazi and Khorjenkov (2007) 4c Figure 4c Tilted walls in Ayla towards the SSW (c) Summary of measurements: direction of tilting patterns observed in Ayla as a function of the direction of the walls. ESE trending walls have systematic tilt toward SSW. al-Tarazi and Khorjenkov (2007) 4d Figure 4d Tilted walls in Ayla towards the SSW (d) Qualitative model showing the types of propagation of the seismic motions during the Nuweiba 1995 earthquake. Ayla was in the compression quadrangle and most of the walls oriented SE were tilted towards SW due to inertia al-Tarazi and Khorjenkov (2007)	At Ayla, a wall in the southern room of the Sea Gate building complex K (Station 20 in Fig. 2 - Plan) is tilted toward SSW at an angle of up to 66° (in its central part) with a declination azimuth of 213° (Fig. 4a). Another example of the same damage pattern is in station 21 (in the western corner of the city wall), where a fragment of the wall is tilted at an angle of 72° with a declination angle of 210° (Fig. 4b). The data of surveyed cases of tilting are summarized in Table 2 and in Fig. 4c. A 24 cases of tilting were observed at walls trending between 105° and 145°, 19 out of these are tilted toward SW and only 5 are tilted towards NE (Fig. 4c). In contrast, only 11 cases of tilting were observed in the perpendicular walls, with a 10°-45° trend, and no systematic tilting was observed. - al-Tarazi and Khorjenkov (2007)	VI+
Lateral shifting of building elements	1	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	5a Figure 5a Shifting of wall fragments in Ayla: (a) Shift toward the SSW of the upper part of a wall attached and perpendicular to the city wall (station no. 1). al-Tarazi and Khorjenkov (2007) 5b Figure 5b Shifting of wall fragments in Ayla: (b) Summary of measurements: direction of shifting patterns observed in Ayla as a function of the direction of the walls. ESE trending walls have systematic shift toward SSW. al-Tarazi and Khorjenkov (2007) 5c Figure 5c Shifting of wall fragments in Ayla: (c) photograph and al-Tarazi and Khorjenkov (2007) 5d Figure 5d Shifting of wall fragments in Ayla: ( d) scheme. Shift toward the epicenter of the upper part of the grave monument during Suusamyr (1992, Ms = 7.3) earthquake in Kyrgyzstan al-Tarazi and Khorjenkov (2007)	In Ayla, a 75 cm wide wall attached and perpendicular to a major city wall (station no. 1 — close to the northern corner of the city wall) has an original trend of 120°. Its upper part is shifted towards SSW (210°) of about 16 cm (Fig. 5a). The lower and undisturbed portion of the wall is 44 cm above the bottom of the excavation trench. The height of the preserved shifted fragment is 18 cm. The wall is composed of cemented sandstone and granite blocks. The upper part of the highly deformed wall attached and perpendicular to the city wall (Station 3 in city Quarter E) was shifted 7 cm toward SSW. The wall trend is 115°, while the direction of shifting is 205°. Total height of the wall is 81 cm above the bottom of the excavation trench. At a later stage, a supporting wall of 84 cm width was built from the southern side in order to impede the collapse from the original wall. Other seven cases of clear shifting were observed (Fig. 5b). Most of them are in walls trending 105°-120°. Three wall fragments were pushed toward the SSW and in one case the wall part was moved towards the opposite direction. - al-Tarazi and Khorjenkov (2007)	VIII+
Rotation of wall fragments around a vertical axis	2 10 or 12	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	6a Figure 6a Rotations of the wall fragments in Ayla. (a) A counterclockwise rotation in the northwestern wall of the 4th city tower. The arrows point to a through-going joint (station no. 2). al-Tarazi and Khorjenkov (2007) 6b Figure 6b Rotations of the wall fragments in Ayla. (b) Ayla city complex A: Upper part of the wall was rotated clockwise by 15° (station no. 10). al-Tarazi and Khorjenkov (2007) 6c Figure 6c Rotations of the wall fragments in Ayla. (c) Angle of rotation as a function of the wall trend: mostly counterclockwise rotations were observed in NNE walls and more clockwise rotations in ESE walls al-Tarazi and Khorjenkov (2007)	In Ayla, there is a rotation pattern in the northwestern wall of the 4th city tower (station no. 2). The height of the remaining wall is 139 cm above the bottom of the excavation trench. The trend of the undisturbed wall is 124°, while the strike of the rotated wall fragment is 115°, this suggesting a counterclockwise rotation on 9° with maximum degree of rotation for the lower row of the wall (Fig. 6a). The maximum horizontal offset between two wall fragments is 8 cm. Another example is at station no. 12 (Ayla's city quarter A), where the upper part of the wall was rotated 15° clockwise by (Fig. 6b). The strike of the undisturbed wall is 117° and the strike of the rotated wall is 132°. The height of the undisturbed wall fragment is 40 cm, while the rotated part is 60 cm high. Width of the wall is 40-50 cm; its length is 2 m. Walls striking 20°-45° revealed six cases of rotation and out of them five are counterclockwise and only one is clockwise (Fig. 6c). The perpendicular walls, trending 115°¬130° revealed five cases of rotation, out of which two cases are counterclockwise and three cases are clockwise. Thus, a systematic picture of rotations is obtained: counterclockwise in NNE trending walls and clockwise in ESE walls (Fig. 6c). - al-Tarazi and Khorjenkov (2007)	VIII+
Fractures across walls	20 2	Figure 2 Plan of the ancient city of Ayla with the locations of the measured stations (numbers inside boxes) described in the text. Hatched diagonal structure is a Wadi bed. BH is a borehole near the Egyptian gate (modified after Whitcomb 1993) al-Tarazi and Khorjenkov (2007)	7 Figure 7 Tilted walls in Ayla towards the SSW (a) In a room of the Sea Gate building complex (Station 20) al-Tarazi and Khorjenkov (2007) 6a Figure 6a Rotations of the wall fragments in Ayla. (a) A counterclockwise rotation in the northwestern wall of the 4th city tower. The arrows point to a through-going joint (station no. 2). al-Tarazi and Khorjenkov (2007)	Long through fissures cutting a whole wall are common phenomena among earthquake damage patterns (Stiros 1996; Korjenkov and Lemzin 2000). Several such patterns were also observed in Ayla. For example, a secondary wall attached and perpendicular to the main city wall (Station 3 in city Quarter E) was cut by a joint. The 55 cm long joint (left one in Fig. 7) crosses two stones of a 121° trending wall. Another joint (Fig. 6a, shown by arrows) cutting through two adjacent stones which are located in the northwestern wall of the 4th city tower (station No. 2). The height of the wall is 139 cm above the bottom of the excavation trench. The trend of the wall fragment is 124°. The described damage pattern occurred during last strong 1995 earthquake (I = VDT, Al-Tarazi 2000), was strong enough to cause significant damage in weak remnants of ancient buildings, especially those already excavated. Local site effects like liquefaction and subsidence could have increased the damage level. - al-Tarazi and Khorjenkov (2007)	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).

Seismic Parameters from al-Tarazi and Khorjenkov (2007)

al-Tarazi and Khorjenkov (2007) estimated an intensity of IX or more and the epicenter was some distance from the site. They estimated that the epicenter was to the NE.

Although based on limited observations the direction of tilt and resystematic block towards NE during Umayyad (748 A.D) and Fatimid (1086 A.D.) earthquakes are likely evidence of seismic motions radiated from the earthquake sources located NE of Ayla.

Liquefaction susceptibility

al-Tarazi and Khorjenkov (2007) suggest that the severity of seismic destruction at Ayla was significantly increased because of site effects. Citing Mansoor, N. (2004), they noted that the location lies in an area of high liquefaction susceptibility, due to the presence of saturated sands at shallow depth. Although previous speculation suggested that an active fault ran through the site, this was apparently disaffirmed by trenching performed by Rucker and Niemi (2005). al-Tarazi and Khorjenkov (2007) also reported that they did not discover offset and rotations affecting the NW town wall as described by Galli and Galadini (2001) and interpret the site history in terms of liquefaction and differential subsidence in agreement with Rucker and Niemi (2005). Ayla's location near the beach and shore strongly suggest that it is subject to liquefaction.

References

Articles and Books

Allison, A. J. (2013). Paleoseismology and Archaeoseismology along the Southern Dead Sea Transform in Wadi 'Arabah Near the municipality of Aqaba, Jordan, University of Missouri - Kansas City. PhD.

Damgaard, K., 2008. Final Report: The 2008 Season of the Islamic Aqaba Project. Circulated, unpublished report

Damgaard, K., Abu-Laban, A., Jennings, M.D., Lorien, P., Seye, C., 2010. Jordan's Port on the China Sea: a preliminary report on the 2010 field campaign of the Aylah Archaeological Project.

Damgaard, K., 2011. Modelling mercantilism: an archaeological analysis of Red Sea trade in the early Islamic period (650-1100 CE). Ph.D. Dissertation, University of Copenhagen, Denmark.

Damgaard, K., 2011. Appendices

Damgaard, K., Jennings, M.D., 2013. Once more unto the beach: a report on renewed archaeological investigations at Aylah. Annual of the Department of Antiquities in Jordan 57.

Galli and Galadini (2001) Surface faulting of archaeological relics. A review of case histories from the Dead Sea to the Alps Tectonophysics 335 291-312

Khouri, R. G. and D. S. Whitcomb (1988). Aqaba: Port of Palestine on the China Sea, Al Kutba.

Korzhenkov, A. and E. Al-Tarazi (2007). "Archaeoseismological investigation of the ancient Ayla site in the city of Aqaba, Jordan." Natural Hazards 42: 47-66.

Mansoor, N. (2004). "A GIS-Based Assessment of Liquefaction Potential of the City of Aqaba, Jordan." Environmental & Engineering Geoscience - ENVIRON ENG GEOSCI 10: 297-320.

Rucker, J. D. and T. M. Niemi (2005). "New excavations of the city wall at Islamic Ayla in ʻAqaba, Jordan." Annual of the Department of Antiquities of Jordan 49: 501-508.

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.

Whitcomb, D. (1994). Art and Industry in the Islamic Port of Aqaba. Special Publications. Chicago, IL, Oriental Institute, University of Chicago: 32.

Excavation Reports

Parker, S. T., et al. (2014). The Roman Aqaba Project Final Report, Volume 1 The Regional Environment and the Regional Survey, The American Schools of Oriental Research.

Websites

The Aqaba Project - Whitcomb - University of Chicago

Aylah Archeological Project

ARCGIS Story Maps for Aqaba