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Institute of Geophysics has established a digital telemetric seismic
network in Tehran region since 1997. Wealth of data from recorded
local earthquakes create an opportunity to image crust and upper mantle in the region. We proposed to study velocity and interface structure of
the crust and upper mantle in the Tehran region using local earthquakes. As a fITst step we obtained a 1-D velocity model by analysis of the
travel-time curves for nearly 20000 P-wave arrival times from 2900 local earthquakes. Recorded earthquakes were classified along the
five separate profiles, and corresponding travel-time curves were analyzed. In addition, a 3-D ray tracing forward modeling code was
written in order to refine model parameters. The results indicate a two-layer crust in the study area. Compressional wave velocity of the first layer is 6.05 km/s and that of second layer is 7.01 km/s. Depths for Conrad and Moho discontinuities were obtained 16 and 46 km
respectively, which well correlates with the results of the previous gravimetric crustal studies. Since, it was difficult to pick arrival time of the direct shear waves, we could not determined the shear wave velocity for the first layer in the crust, but it found to be 3.90 and 5.20 km/s for
the second layer of the crust and the Moho, respectively