InSAR analysis of the 2008 Reno-Mogul earthquake swarm: Evidence for westward migration of Walker Lane style dextral faulting



[1] Analysis and modeling of InSAR data covering the 2008 Reno-Mogul M 4.7 earthquake swarm indicate that the main event was produced by slip on a previously unrecognized strike-slip fault in the Reno basin. Deformation of 0.5–2.5 cm in radar line-of-sight was produced by the main event and post-seismic slip over an area of more than ∼150 km2. This earthquake is one of the smallest magnitude events modeled with InSAR to date in the seismically active western Basin and Range, and it provides new insights into regional neotectonic relations. Inverse modeling of the InSAR data suggests that the earthquake swarm was generated by 25–75 cm of dextral displacement on a N44W-striking fault with a ∼3 km rupture length and a rupture depth of ∼2 km. The InSAR-detected strike-slip ground deformation is unique for the Reno basin which is in the purely extensional domain of the Sierra Nevada-Basin and Range Transition Zone, an area dominated by north-striking normal faults. The InSAR modeling of the 2008 earthquake swarm supports the concept of westward migration of Walker Lane transcurrent faulting and overprinting of extensional Basin and Range structures, in this case the westward migration of dextral shear associated with the northern Walker Lane into the extension-dominated Reno basin.