Source Time Function of Zagros Region Earthquakes

The Zagros Fold-Thrust Belt (ZFTB) is a collision zone, which is formed due to the northeast motion of the Arabian plate toward the central plateau of Iran. An interesting aspect of the nucleation (point source) of large Zagros area earthquakes is the emergent nature of their source time function. These emergent source time functions may reflect a difficulty in breaking barriers,the localized region of the fault, which remains unbroken at the completion of the dynamic fault process that may commonly occur during the rupture of large earthquakes. Propagation and instrumental effects are deconvolved from the long period P and SH wave records of GDSN stations to obtain the teleseismic source time function using a damped least squares inversion. The inversion has the additional constraint that the source time function is positive everywhere. The comparison of stress drop data show that the Kazerun fault has very low trend energy release than to other parts of the region.