Seismic Tomography of the Arabian-Eurasian Collision Zone and Surrounding Areas

摘要

We developed P- and S- wave velocity structures in the crust and upper mantle in the Arabian-Eurasian collision zone and surrounding areas, including Iran, Arabia, Eastern Turkey, and the Caucasus. We first obtain Pn and Sn velocities using local and regional arrival time data. Second, we obtain the 3-D crustal P and S velocity models. Third, we extend the model into the upper mantle and transition zone by combining local, regional and teleseismic data and crust model constraints. To extend the model deeper into the mantle through the upper mantle transition zone, ISC/EHB data for P and PP phases are combined with the ABCE data. To counteract the 'smearing effect,' the crust and upper mantle velocity structure, derived from regional travel-times, is used. An adaptive grid method based on ray density is used in the inversion. A P-wave velocity model extending down to a depth of 2000 km is obtained. regional- teleseismic tomography provides a high-resolution, 3-D P-wave velocity model for the crust, upper mantle, and the transition zone. The crustal models correlate well with geologic and tectonic features. The upper mantle tomograms show the images of the subducted Neotethys slab. The slab geometry is quite complex, reflecting the history of the changes in the plate motions and collision processes. Vp/Vs tomography was also determined in the study region, and an attenuation tomography was obtained in Iran.