Reza Mansoori

The 20 December 2010 M 6.3 earthquake near Rigan in southeastern Iran occurred on a previously unknown active fault in the southern Lut block. Its position was inferred by Walker et al. (2013) using Interferometric Synthetic Aperture Radar and the analysis of aftershocks recorded by the two permanent seismological networks in Iran. In this article, we analyze previously unavailable data from six temporary stations deployed immediately after the 2010 Rigan earthquake. We locate the aftershock sequence using two techniques: (1) a time-reversal method of our own, derived from the Waveloc algorithm of Langet et al. (2014) and (2) the NonLinLoc algorithm of Lomax et al. (2000). We detect more than 3900 events over the 7-day period of the deployment, 46 of which we consider to be well constrained. Our locations lie on a northeast–southwest trend that corroborates the inferred fault location and provides further evidence of the presence of this hidden fault in the southern Lut block. The occurrence of hidden faults in this tectonically active region suggests that a re-evaluation of local and regional seismic hazard may be necessary.