The 2015 Gorkha earthquake: A large event illuminating the Main Himalayan Thrust fault

Abstract

AbstractThe 2015 Gorkha earthquake sequence provides an outstanding opportunity to better characterize the geometry of the Main Himalayan Thrust (MHT). To overcome limitations due to unaccounted lateral heterogeneities, we perform Centroid Moment Tensor inversions in a 3‐D Earth model for the main shock and largest aftershocks. In parallel, we recompute S‐to‐P and P‐to‐S receiver functions from the Hi‐CLIMB data set. Inverted centroid locations fall within a low‐velocity zone at 10–15 km depth and corresponding to the subhorizontal portion of the MHT that ruptured during the Gorkha earthquake. North of the main shock hypocenter, receiver functions indicate a north dipping feature that likely corresponds to the midcrustal ramp connecting the flat portion to the deep part of the MHT. Our analysis of the main shock indicates that long‐period energy emanated updip of high‐frequency radiation sources previously inferred. This frequency‐dependent rupture process might be explained by different factors such as fault geometry and the presence of fluids.