Paleoseismology and Archaeoseismology along the Southern Dead Sea Transform in Wadi 'Arabah Near the municipality of Aqaba, Jordan

Abstract

The southern Wadi ‘Arabah Valley in Jordan provides an ideal location to investigate both the paleoseismology and archaeoseismology of the region because it is situated directly along the active Dead Sea transform, and because the area has a long history of human occupation. The region is rich in archaeological ruins as a result, many of which have been damaged by earthquakes in the historic past. An archaeoseismic excavation conducted at Early Islamic Ayla (7th-12th C.) in the city of Aqaba, Jordan revealed that a 3.5 m-long section of original city wall that leans out toward the Gulf of Aqaba was likely damaged because of liquefaction caused by ground shaking from a historic earthquake, and was buttressed shortly thereafter. Stratified pottery and radiocarbon dated charcoal collected from within and beneath the revetment wall suggest a revetment construction in the early 11th century. Based on known historical earthquakes of the region, damage to the Ayla city wall likely occurred as a result of the A.D. 1033 earthquake. Paleoseismic data collected at the Sisters’ School site in Aqaba, and from the Taba Sabkha trench located 35 km north of the city, suggest that southern Wadi ‘Arabah was more seismically active during the Holocene than previously understood. In Taba, paleoseismic trenching data suggests that between two to four earthquakes ruptured the sabkha from the 8th to the 16th centuries, although a three-event model is preferred. When correlated with major earthquake catalogs, these ruptures likely represent the A.D. 746/749 or 757 earthquakes, the March 1068 event, and either the 1546 or 1588 earthquake. At the Sisters’ School site, at least five early to mid-Holocene earthquakes are visible in the southwest trench wall, as is evidence of paleoliquefaction in the form of clastic sand and silt dikes. Optically stimulated luminescence and radiocarbon dates suggest that the Sisters’ School site dates to as early as the Pre-Pottery Neolithic and as late as the Bronze Age. Ashy deposits and a fire pit exposed in cross-section, dated to 6200-3000 B.C. and 4986-4840 B.C. respectively, also suggest early human occupation at the head of the Gulf of Aqaba in antiquity