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Mahsa Abd Etedal, Institute of Geophysics, Tehran, Iran (Islamic Republic of Iran)
Mohammad Reza Gheitanchi, Institute of Geophysics, Tehran, Iran (Islamic Republic of Iran)
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One of the basic factors responsible for earthquakes is the appropriate crustal velocity structure. The crustal velocity model can be helpful to determine the hypocenter of the earthquakes more properly. In this study, we investigate the velocity structure of the crust and upper mantle beneath the Khorasan region, in the North Eastern Iran. We use seismic data collected by the local seismological network that was deployed in Khorasan. The records of about 4449 earthquakes obtained by this network occurring during 1996-2007 were used in this study. We selected the 1450 well located earthquakes to invert. These earthquakes were recorded by at least ten seismic stations. In the beginning an initial crustal model having 10 layers was obtained by reading Pn and Pg phases from recorded waveforms in Khorasan seismic network and analyzed their travel-time curves. Then using a tomography method, we refined the depth and velocity parameters of each layer. We used the software that was developed by Kissling (1993). Taking into account the results that was obtained in this study; we provided the contour maps for the velocity and depth variations. Our interpretation is in good agreement with the geological evidence and the result of other studies.
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