Shear-Wave Velocity Tomography of the Lithosphere-Asthenosphere System beneath the Iranian Plateau

摘要: We conducted a tomographic inversion of Rayleigh-wave dispersion to obtain 2D phase and group velocity images in the 10-100 s period range shear-wave structures for Iranian plateau. For this purpose, fun- damental mode Rayleigh waves, recorded along 1586 paths by 29 broadband sta- tions, was identified applying frequency time analysis (FTAN) each epicenter-station path which simultaneously satisfies two-station method condi- tions. The fundamental modes FTAN have been used determine path-average interstation velocities at selected periods. With pro- cedure, 243 curves were processed to- mographic maps Yanovskaya-Ditmar formulation periods range. Averaged velocities, represent six rather homogeneous regions, are computed. Finally, we fully non- linear procedure derive elastic structure lithosphere asthenosphere main structural seismotectonic features dense coverage plateau permits us duce that substantially higher lateral resolution compared cur- rently available from global regional studies. Tomographic high frequencies well correlated with upper crust structure, especially sediment layers thickness. Estimated corre- lated shield-like Zagros. A low-velocity zone (LVZ) is not detected Alborz or south Caspian basin, can imply thrusting oceanic southern Sea under south. LVZs derived region east Iran, central Kopeh Dagh.