UC San Diego

Abstract We use surface deformation measurements including Interferometric Synthetic Aperture Radar data acquired by the ALOS‐2 mission of the Japanese Aerospace Exploration Agency and Global Positioning System (GPS) data to invert for the fault geometry and coseismic slip distribution of the 2015 M w 7.8 Gorkha earthquake in Nepal. Assuming that the ruptured fault connects to the surface trace of the Main Frontal Thrust (MFT) fault between 84.34°E and 86.19°E, the best fitting model suggests a dip angle of 7°. The moment calculated from the slip model is 6.08 × 10 20  Nm, corresponding to the moment magnitude of 7.79. The rupture of the 2015 Gorkha earthquake was dominated by thrust motion that was primarily concentrated in a 150 km long zone 50 to 100 km northward from the surface trace of the Main Frontal Thrust (MFT), with maximum slip of ∼ 5.8 m at a depth of ∼8 km. Data thus indicate that the 2015 Gorkha earthquake ruptured a deep part of the seismogenic zone, in contrast to the 1934 Bihar‐Nepal earthquake, which had ruptured a shallow part of the adjacent fault segment to the east. Key Points The geodetic moment is in good agreement with the seismic moment Rupture likely occurred on the Main Frontal Thrust (MFT) that dips at an angle of 7° The shallow part of the MFT was not ruptured by the 2015 earthquake and poses future seismic hazard