ACTIVE DEFORMATION IN FRONT OF DEZFUL EMBAYMENT: WHY THE DOROUD SEGMENT OF MAIN RECENT FAULT IS MORE ACTIVE?

The major structures of the Zagros Fold-and-Thrust belt (FTB) in SW of Iran, mainly consist of NW-SE thrusts and folds in whole of the belt. In the East of the Kazerun fault, the strike-slip faults also dominate. In the Northernmost segment of the Kazerun fault the other active strike-slip fault with the NW-SE trend, so-called, Main Recent Fault (MRF), is activating. The additional occurrence of, nearly, N-S-striking oblique (to the FTB) was revealed through field study, spot images, DEM, drainage anomalies and preexisting information in west of Kazerun fault system. They show right lateral displacement and accommodating of the deformation due to piercing of the Dezful Indenter (DI) onto the deformable High Zagros area. As on one hand, MRF is an active hazardous fault, and on the other hand, these N-S faults segmented them, the study of these N-S faults is significant. The study of the N-S faults helps us to find the geometry of the Kazerun fault termination where it meets the MRF. It also leads us to quantify the shortening of the deforming High Zagros province. Some parts of the deformation ,in addition to N-S shortening, contributes by strike-slip movement along the MRF due to oblique convergence of Arabian plate toward Central Iran. The geometry of DI shows the most deformation accommodates by the Doroud segments of MRF. So it is more active than the others.