Multiple source analysis from InSAR data and new insights into fault activation: The 2005 Zarand, Iran, earthquake

We have reinterpreted the causative fault parameters of the 2005 Zarand earthquake in the light of a new imagery study using Interferometric Synthetic Aperture Radar (InSAR). By conducting a joint inversion of two InSAR datasets, we can characterize the rupture as it relates to complex local structures. At first, the mainshock ruptured a nearly pure reverse fault, dipping similar to 65 degrees NNW in the basement below the southeastern area of Zarand. Two more fault segments were subsequently activated: an oblique-normal fault segment parallel to the first segment, dipping 61 degrees to the south, and a normal-oblique fault segment at the eastern termination of the rupture zone. The first fault segment ruptured the surface, while slip along the other two segments was confined to the lower sedimentary strata.