3D crustal modeling and seismicity of the Eastern Mediterranean and the Egyptian coastal zone

Three-dimensional gravity modeling has been performed for the Eastern Mediterranean including the northeastern Egyptian off-shore area. The gravity models and seismic profiles indicate that a transition from two layer continental crust to a simple layer oceanic crust takes a place along the Levantine margin. The transition along three profiles is located beyond the north African continental margin and it is quite gradual. The crust under the Levantine basin is typically oceanic and slightly thin with 13 km thickness, however it is typical continental under the Egyptian off-shore and having 30 km thickness. The obtained results reflect a large sedimentary sequence of 14 km under the Levantine basin. Since the sediments recovered by the Oceanic Drilling Program Leg160 in the eastern Mediterranean ranged from Pleistocene to Cretaceous, this reflects fairly high sedimentation rate. Distribution of recent earthqu ake foci indicates that almost all earthquakes occurred along the western and central segments of the Cyprean arc while they completely disappear along the eastern segment. This means that collision between Cyprus and the Eratosthenes seamount is marked by seismic activity and clearly affects the shape of the Cyprean arc. This collision represents a transition zone between active compression and probable subduction in the western segment and diffuse transtension through the eastern part of the arc. Incipient collision between Cyprus and Eratosthenes seamount probably began in Pleistocene time. © 2006 Akadémiai Kiadó, Budapest.