Deformation analysis on Zhongba (Tibet) earthquakes as constrained by InSAR measurement

Abstract

Differential Radar Interferometry (DInSAR) is capable of all-weather and all time observation. It is an unprecedented and profound developing potential space technology with the superiority of continuous space coverage compared to other discrete measurements. The Envisat images from ESA were used in this paper to derive the co-seismic deformation interferograms caused by the Zhongba Ms6.7 earthquake on July 12, 2004 and Ms6.5 earthquake on April 8, 2005 occurred in Tibet. The results indicate that two earthquake events caused the deformation in an area of 20 km with a maximum LOS change about 19.0 cm and 30.5 cm respectively. Adopting isotropic elastic half-space dislocation model, we estimated that two earthquakes epicenter locate at E 83.71°, N 30.70° with a seismic moment tensor Mw6.1 and E 83.72°, N 30.52° 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 NNE Palongcuo-Cangmucuo fault zone.