Strain Partitioning in West-Central Zagros Fold and Thrust Belt: Implication for Seismic Hazard Analysis

This paper provides some documents to reintroduce the active faults and their ability to generate strike-slip earthquakes in west-central Zagros Fold and Thrust Belt (ZFTB). For this purpose, the structural and geomorphic arguments were presented to improve the fault kinematics and segmentation need for calculation of the largest magnitude due to their reactivation within interested area. Slip rates along strike slip faults, which have already been estimated, are used to estimate the probable recurrence interval time of the events. The strike-slip faults extend in N-S direction around ۵۲oE from frontal part of ZFTB to the north and continued along the strike of the Belt, i.e. the Main Recent Fault (MRF), at the rear of the belt. The MRF has been considered as a major dextral strike-slip fault in the context of the tectonic model of the strain partitioning. It was shown that MRF is not unique in the strain partitioning system, but the High Zagros Fault (HZF) in the domain of the High Zagros Belt (HZB) is contributing in the partitioning of strain of the Arabian plate oblique convergence. Therefore, both of HZF and MRF can potentially cause the strike-slip events. Our data shows that the lengths of fault segments along MRF increase toward northwestward. In case of HZF and Kazerun faults, the segments' lengths increase in southeast and northward, respectively. The growth of the length of the segments is in accordance with the increase of the slip-rate. Consequently, it was expected that the seismicity would increase in these directions.

Keywords:

Strain Partitionary , Seismic Analysis , Thrust Belt , Westcentral Zagros Fold