The InSAR coseismic deformation observation and fault parameter inversion of the 2008 Dachaidan Mw 6.3 earthquake

On November 10, 2008, an Mw 6.3 earthquake struck the Dachaidan region of Qinghai Province. The ascending and descending synthetic aperture radar (SAR) data from EnviSat satellite and the differential interferometric SAR (DInSAR) technology are used to extract the coseismic deformation field. The uniform dislocation model is used to determine the fault parameters, the grid iteration method is then used to find the optimal dip angle, and the non-uniform dislocation model is used to obtain the detailed slip distribution simultaneously. The results show that the earthquake uplifts the hanging wall up to ~8.5 cm and ~10 cm along the line of sight of the descending and ascending tracks, respectively. The optimal dip angle is 47.9°. The coseismic slip doesn't rupture to the earth surface, and mainly occurs at a depth range from 8.2 km to 23.7 km, with the maximum and average slip of 0.5 m and 0.19 m, respectively. The average rake angle is 104.9°. The inverted earthquake moment is 3.74×1018 N·m, and the moment magnitude Mw is 6.35. © 2015, Surveying and Mapping Press. All right reserved.