GPS constrained coseismic source and slip distribution of the 2013 Mw6.6 Lushan, China, earthquake and its tectonic implications

The 20 April 2013 Lushan earthquake occurred on the southern section of the Longmen Shan fault system. Using GPS data from 33 continuous stations, we derive a three-dimensional coseismic displacement field of the earthquake and invert for the location, geometry, and slip distribution of the fault rupture. Our study result indicates that the earthquake occurred on a reverse fault striking N28 degrees E and dipping 43 degrees to the NW, with the maximum slip located at 30.292 degrees N, 102.943 degrees E, and 13km depth. The rupture is dominated by thrust faulting, with a slight but still statistically significant sinistral component. The seismic moment release is 9.5x10(18)Nm, equivalent to a Mw6.6 earthquake. Our results suggest that at the southern end of the Longmen Shan fault zone near the triple junction with the Xianshuihe and Anninghe faults, the kinematic deformation field is no longer block-like, but broadly distributed to accommodate the buttressing effect of deformation around the fault triple junction. Key Points A set of three-dimensional GPS coseismic displacement data of Lushan earthquake is provided Rupture is dominated by thrust faulting with a significant sinistral component Main rupture is at 13 km depth, with moment release equivalent to Mw6.6 event