Coseismic Slip from the 6 October 2008, M_w6.3 Damxung Earthquake, Tibetan Plateau, Constrained by InSAR Observations

摘要

Coseismic deformation fields of the 6 October 2008 M w 6.3 Damxung earthquake were obtained from interferometric synthetic aperture radar by using three descending and two ascending Envisat images. Significant coseismic surface deformation occurred within 20 km × 20 km of the epicenter with a maximum displacement of ~0.3 m along the satellite line of sight. We model a linear elastic dislocation in a homogeneous half space and use a nonlinear constraint optimized algorithm to estimate the fault location, geometry and slip distribution. The results indicate a moment magnitude M w 6.3, and the earthquake is dominated by oblique normal and right-lateral slip with a maximum slip of 2.86 m at depth of 8 km. The rupture plane is about 15 km × 14 km with strike S190°W and dip 55° to NW, located at a secondary fault of the Southeastern Piedmont of the Nyainqentanglha Mountains. Slip on normal faults in the Tibetan Plateau contributes to the rift evolution.