Fault Slip Distribution Inversion and Co-seismic Deformation of the 2017 Jiuzhaigou M_S7.0 Earthquake Based on InSAR

An M_S7.0 earthquake struck Jiuzhaigou, Sichuan province on 8 August 2017. This work obtained two LOS co-seismic measurements by carrying out the "Two-pass" differential interferometry on two tracks (1 ascending and 1 descending) of ERS sentinel-1A images firstly; Then the co-seismic displacements located in near and far field were subsampled with Quad-tree sampling and uniform sampling methods, respectively. The fault slip distributions were built based on the rectangular dislocation model in an elastic half space from the subsampled measurements. The results show that:① the both inteferograms display a similar butterfly shape caused by Jiuzhaigou earthquake, with the max amplitude of -20.3 cm and 11.3 cm, respectively. ② The seismogenic fault is dominated by left-lateral strike with little normal faulting, with strike of 154° and dip of 82°. ③ The fault slip is mainly happened in the depth between 2 km and 15 km, with maximum slip of 0.68 m located at 9km depth, and the average rake of -22°. The moments released by the earthquake is about 9.6×10¹⁸ Nm (M_W6.6), which is almost consistent with the seismology research.