Crustal Velocity Structure In Central of Iran Using Local Earthquakes

Earthquakes travel times inversion for determination of velocity structure of crust is one of the most important topics in seismology. In the simultaneous inversion method, the parameters of earthquakes and velocity model are determined initially and are improved during inversion steps. In this study, we have used more than 36000 calculated travel times for first arrivals of 8000 earthquakes, which occurred central of Iran (bounded 30N-34N & 50E-56E) to estimate P wave velocities and the thickness of the crust in this region. then about 564 earthquakes that located with high accuracy were selected for this study.by applying the results of previous studies and random models, the discontinuities of 10 Km, 20Km, and 44 Km Moho depth were assumed. The velocity 6 Km/s for depth down to 10 Km, 6.2 Km/s down to 20 Km, 6.5 Km/s down to 44 Km, and 8.2 Km/s for below the Moho were determined. We used new data and 1-D model to 3-D inversion and finally 3-D velocity structure was calculated by FAST software .We also used two deferent resolution tests to understanding where was reliable in the model.