Late Holocene paleoseismic timing and slip history along the Missyaf segment of the Dead Sea fault in Syria
by
Mustapha Meghraoui
EOST, Institut de Physique du Globe, Strasbourg, France
Coauthors: Francisco Gomez (Institute for the Study of the Continents, Cornell University), Reda Sbeinati (Department of Geology, Atomic Energy Commission, Damascus, Syria), Jerome Van der Woerd (EOST, Institut de Physique du Globe, Strasbourg, France), Michel Mouty, Fouad Hijazi (Department of Remote Sensing, Higher Institute for Applied Science and Technology, Damascus, Syria), Abdul Nasser Darkal (Department of Geology, Damascus University, Damascus, Syria), Ryad Darawcheh, Youssef Radwan, Haitham Al-Najjar, Ihsan Layous (Department of Geology, Atomic Energy Commission, Damascus, Syria), Riad Al-Ghazzi (Department of Remote Sensing, Higher Institute for Applied Science and Technology, Damascus, Syria), Muawia Barazangi (Institute for the Study of the Continents, Cornell University)

We investigate the timing of Holocene earthquakes and related slip rate along the main segment of the Dead Sea fault south of the Ghab pull-apart basin in western Syria. The 60-70 km long Missyaf segment consists of a single fault branch of the north-south trending left-lateral fault at the plate boundary between Africa and Arabia. The late Quaternary tectonic activity along the fault is characterized by (1) deflected streams with consistent left-lateral displacements of different sizes (50 to 300 m), and (2) evidence of large shutter-ridge structures and small pull-apart basins. Microtopographic surveys and trenching across the fault at two sites document the size and timing of paleoseismic events and the related faulting behaviour. Near El Harif village, the fault cut across a presumably Roman aqueduct (younger than 408 BC) and induces 13.6 ±0.1 m of left-lateral displacement. Nearby trench-excavations and test pits exhibit the fault with the shear zone affecting a succession of young alluvial deposits of a terrace meander. First radiocarbon dating of the faulting events with vertical displacements reveal the occurrence of a large seismic event prior to 348 BC - 810 AD, a penultimate event between 650 - 1152 AD and the most recent event between 979 - 1255 AD. The three most recent events being most likely responsible for the aqueduct total displacement, it implies a coseismic left-lateral movement of 6.8 m per event at this location and a slip rate of about 6 - 7 mm/yr for the last 2000 years. The correlation with the historical seismicity catalogue suggests that the most recent faulting event may correspond to the well documented large earthquake of 1170 AD for which we estimate Mw = 7.3 - 7.5.

Date received: March 12, 2002

Copyright © 2002 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caiq-77.