1-D Velocity model for syria from local earthquake data and new seismicity map in Syria

We performed inversion of P and S wave arrival time data from a set of 542 events recorded by the Syrian National Seismological Network during 1995-2004 to determine 1-D velocity structure beneath Syria. We determined both P and S wave velocity structures with a set of station corrections. The P wave velocity in the shallow part in the new model is faster than the current model, while the P wave velocity in the lower part of crust in the new model is slower than that in the current model. We performed hypocenter determination using this new velocity model and compared the relocated hypocenters to hypocenters determined for the current crustal model used by National Earthquake Center of Syria. There is a significant difference in the distributions of their focal depths. When the new velocity model is used, the number of the events in the depth range between 0 and 5 km increases, while that in the depth range between 10 and 15 km decreases. The RMSs of the arrival time residuals obtained by the new model are significantly smaller than those obtained by the current model, which suggests that it is possible to improve the accuracy of hypocenter determination using this new velocity model. We find qualitative correlations between the obtained station corrections and surface geology.