Active strike-slip faulting, diapirism and seismic hazards. The case of the Kareh Bas fault and the associated Dandenjan salt extrusion in the zagros Mountains, SW Iran

Abstract

Strike-slip salt diapir systems have been scarcely investigated and have probably been underrecognized. The western Fars Arc of the Zagros Mountains hosts the most remarkable example of salt extrusions associated with seismogenic strike-slip faults within an oblique collisional setting. This study, mainly based on field mapping and observations carried out in the Kareh Bas fault system and the Dandenjan Diapir, explores several issues with practical implications related to these active fault-salt systems: (1) role of precursor diapirs on the initiation of shortening structures; (2) fault segmentation controlled by precursor diapirs, emergence of diapirs, and the development of pull-apart basins; (3) the relative timing of emergence of salt extrusions associated with a propagating strike-slip fault; (4) Quaternary deformation and paleoseismic evidence associated with the Kareh Bas fault; (5) the impact of the salt detachment depth on the seismogenic potential of the segmented Kareh Bas fault system; and (6) clustering of large potentially coseismic landslides in the vicinity of the Kareh Bas fault system.