Seismicity and volcanism in the rifted zone of western Syria

Abstract

At the northern part of the Dead Sea fault zone (DSFZ), in the continuity with the Red Sea, Syria has a long record of active seismisity and recent volcanism. Field observations, physical effects on ancient building structures and movement analysis show that tectonics is still active at present time. A seismicity map has been established, based on the analysis of historic and recent seismicity, seismic parameters and laboratory oedometric experiments. The movement rate along the Syrian rift is estimated at less than 1 to 2.7–3.3 mm/year, with a seismic acceleration coefficient ( Z) of 0–0.25 cm/S 2 .The whole Syria territory is divided into five seismic zones of decreasing intensity, from 1 to 5, respectively. Earthquakes may occur in the whole country, but most epicenters, with the highest magnitude, are located within the first two seismic zones, including the Syrian rift and associated volcanism. A closer comparison with structural–petrological data shows, however, this recent volcanic activity, issued from a shallower mantle source, tends to distantiate from the rift zone. Major seisms appear to be related either to ancient, extinct volcanoes (Cretaceous age) or to superficial deformation of the sedimentary cover. Their intensity has significantly decreased during the last millennium.