EQ V is the oldest paleoseismic event identified in the Sisters’ School trench in Aqaba, Jordan. The trench was an approximately 140 m by 100 m building foundation trench located about 1 km northeast of the head of the Gulf of Aqaba and about 1.3 km north of Early Islamic Ayla. The site exposed numerous fault strands within the urban Aqaba coastal zone, where the exact inland trace of the Aqaba fault remains difficult to identify because of modern development.
Allison (2013) interpreted the faults exposed at the Sisters’ School site as most likely related not to the Aqaba fault itself, but to the West-Aqaba fault, located west of the Aqaba fault strand. The trench also exposed evidence for northwest-trending cross faulting. Strike and dip measurements indicate that many faults trend close to north or northeast, broadly consistent with the West-Aqaba fault, while another group of faults trends northwest and may represent a transverse cross fault, possibly Cross Fault 6. The faulting therefore appears to record both strike-slip deformation and a normal-faulting component associated with local cross-fault motion.
EQ V is expressed in the basal part of the southwest trench wall, rupturing as high as unit SS-22, and is capped by unit SS-19. The principal paleoseismic evidence is the upward termination of faults below this capping unit, together with vertically offset stratigraphic units and mismatched unit thicknesses across fault lines. Allison attributed these mismatched thicknesses to strike-slip motion, implying that lateral displacement juxtaposed originally different parts of the same beds across the fault zone.
A terminus post quem for EQ V is provided by OSL sample #2 from unit SS-24, which was ruptured by EQ V. The sample was collected between meter marks 20 and 21 at the base of the trench. This sample yielded an OSL age of 6.9 ± 1.7 ka, equivalent to 6600-3200 BCE. A terminus ante quem is provided by two younger samples from overlying stratigraphy. OSL sample #4, collected from overlying unit SS-10, yielded an age of 6.6 ± 1.6 ka, equivalent to 6200-3000 BCE. In addition, radiocarbon sample RC-SS #1, recovered approximately 10 m east of the trench log from a fire pit in unit SS-10, produced a laboratory age of 6015 ± 25 yr BP and a calibrated age range of 4986-4840 BCE (2σ). Taken together, these samples constrain the age of EQ V to sometime between 6600 and 4840 BCE.
- Fig. 1.2 Location map from
Allison (2013)
Location map of research sites in southern Wadi ‘Arabah, Jordan
(Google Earth, 2013a)
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Allison (2013)- Fig. 4.1 Location map with
Geomorphology from Allison (2013)
Geologic map of the southern Wadi ‘Arabah. The Taba Sabkha trench location is shown at the top of the map (modified after Garfunkel, 1970). DST faults in Gulf of Aqaba from Hartman, 2012.
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Allison (2013)- Fig. 5.1 Location map with
faults from Allison (2013)
Location of Dead Sea transform faults mapped both offshore in the Gulf of Aqaba (white lines) and on land (dashed black lines). The solid back lines indicate transverse cross-faults mapped throughout the city of Aqaba, Jordan. Map from Tibor et al., 2010.
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Allison (2013)- Fig. 5.15 Fault Map around
trench site from Allison (2013)
Map of the city of Aqaba showing locations of the active cross faults (CF 1-5) mapped from aerial photos and discovered during the archaeological excavations of J-East in Roman-Byzantine Aila. The proposed location of cross fault 6 (CF-6) was determined as a result of this paleoseismic study at the Sisters’ School site. Locations of other major archaeological sites in the city are also shown (after Thomas et al., 2007).
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Allison (2013)- Fig. 5.2 Location map from
Allison (2013) (in Google Earth)
Location of Dead Sea transform faults mapped both offshore in the Gulf of Aqaba (white lines) and on land (dashed black lines). The solid back lines indicate transverse cross-faults mapped throughout the city of Aqaba, Jordan. Map from Tibor et al., 2010.
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Allison (2013)- Fig. 5.3 Detailed Location
map from Allison (2013)
Location map of Sisters’ School trench within the city of Aqaba, Jordan. The building foundation trench is outlined in black and the arrow points toward the southwest wall which contains the majority of faults identified at the site. Topographic contour lines, trending generally NW-SE, are shown with a 1 m contour interval.
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Allison (2013)- Fig. 5.4 Site plan from Allison (2013)
Top plan map of the Sisters’ School trench within the city of Aqaba, Jordan. The building foundation trench is outlined in black, and a red arrow points toward the southwest wall that contains approximately half of all the faults identified at the site. Faults and dikes identified in the trench walls are marked with either a short black line or a red strike and dip symbol where available and where space would allow. Fault lines in black are drawn perpendicular to their respective trench wall for uniformity and do not indicate direction of strike.
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Allison (2013)- Table 4.1 OSL and Radiocarbon Dating
Dating Results from Allison (2013)
Geochronology Of Sisters’ School Trench, Aqaba, Jordan
Optically Stimulated Luminescence (Osl) Dating Results And Radiocarbon Dating Results
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Allison (2013)Figure 5.8
Cross-section of both the north and south Taba Sabkha trench walls showing faulting, stratigraphic offset, and radiocarbon dates of charcoal samples collected.
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Allison (2013)
Figure 5.9
Paleoseismic faulting and a generalized stratigraphic section of the Sisters’ School southwest trench wall in Aqaba, Jordan. Colored stratigraphic units correlate to the colored cross-section of the SW trench wall (see Figure 5.8).
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Allison (2013)
