Focal mechanism analysis and parameter estimation of Zhangbei-Shangyi earthquake from differential SAR inter-ferometry
摘要
On 10 January, 1998 an earthquake of Ms=6.2 occurred in the Zhangbei-Shangyi region of North China. The surface seismic deformation was measured in the previous study using the 3 pass ERS-1/2 SAR differential inter-ferometric technology (D-INSAR). In this note the focal mechanism of Zhangbei-Shangyi earthquake is estimated from the D-INSAR measurement of surface deformation based on a standard elastic dislocation model for seismic displacement. The inversion procedure is an iterative, linear least-squares algorithm. Through the relation between the focal parameters and displacement in the line of sight direc-tion measured in the radar interferogram, the optimum focal parameter set is derived. The results show that the seismic fault of Zhangbei-Shangyi earthquake is a thrust fault dip-ping SW with a large right-lateral displacement component. The strike and dip are 95°and 30°respectively on a fault patch of 12 km long by 14 km wide. Its hypocenter is located at N40°58’, E114°21’, and 7.5 km in depth.