ARCHAEOSEISMOLOGY OF OFFSET RUINS ALONG THE SOUTHERN DEAD SEA TRANSFORM, JORDAN

The field of archaeoseismology is the study of ancient earthquakes based on their effects on human constructions found in the archaeological record. Archaeological sites that are built over active faults are unique because of their potential to yield the precise date and magnitude of individual historical earthquakes. Furthermore, the age and areal distribution of earthquake-damaged features can help refine the epicentral location of past earthquakes. The main objective of the Wadi Araba Earthquake Project is to use detailed archaeological excavation and mapping to define and date archaeological structures that have been offset by earthquake motion in order to better our understanding of ancient earthquake sources, develop models of earthquake recurrence, and improve our understanding of future seismic hazards along the Dead Sea Transform faults in Jordan. Our paleoearthquake data from trenches excavated across the active faults in Aqaba indicate repeat motion on the faults with the latest scarp forming around A.D. 1045-1278 (probably in the historical earthquakes of 1212 or 1068). The ancient Islamic walled city of Ayla is known from Arabic historians to have been completely destroyed in the earthquake of March 18, 1068. Archaeological excavations at Ayla revealed walls that were tilted, slumped, and shifted completely off their foundations and evidence for liquefaction. Recent excavations of a monumental Byzantine mudbrick church structure indicate that a portion of this building collapsed in the earthquake of May 19, 363 A.D. This date is derived from over 100 coins of Constantius II (337-361 A.D.) found beneath tumbled mudbrick walls. Subsequent inhabitants repaired wall join separations and fissures in the standing walls. These fissures were later faulted to the surface of the cultural debris and sediments dated to the 7th-8th century. One 4th century wall at the south end of the site appears to be offset by at least two earthquakes. These data indicate primary tectonic faulting in Aqaba in the 4th and 11-13th century. Our excavations at the Qasr Tilah archaeological site that is built over the Wadi Araba fault south of the Dead Sea indicate at least three post 7th Century earthquakes. These data clearly show that both slip and earthquake chronology data can be gleaned from key archaeological sites.