利用欧洲Envisat雷达遥感图像,获取了2004年7月12日和2005年4月8日西藏仲巴Ms6.7和Ms6.5地震的InSAR同震形变场。结果显示这两次地震造成震中区20km×20km范围内近EW向升降变形,最大变形分别为19.0cm和30.5cm。根据均匀弹性半空间模型,推断这两次地震是以正断为主的破裂过程,震中位于83.71°E,30.70°N,震级Mw6.1和83.72°E,30.52°N,震级Mw6.2,其最大倾滑量分别为1m和1.4m,两次地震均发生在NW向的雅鲁藏布江断裂带和近NS向的帕龙错-仓木错断裂的交汇部位。
The Envisat images from ESA were used to derive the coseismic deformation interferograms caused by the Zhongba Ms6.7 earthquake on July12,2004 and Ms6.5 earthquake on April 8,2005 occurred in Tibet.The results indicate that two earthquakes caused the deformation in an area of 20 km with a maximum LOS change about 19.0 cm and 30.5 cm recpectively.Adopting isotropic elastic half-space dislocation model,we estimate that the two earthquakes epicenter locate at E83.71°,N30.70° with a seismic moment tensor Mw6.1 and E83.72°,N30.52° with a seismic moment tensor Mw6.2,dominated by normal fault fracture with maximum slip 1 m and 1.4 m,located at the intersection of NW Brahmaputra fault zone and the near side NS Palongcuo-Cangmucuo fault zone.