Three-Dimensional Deformation Field of Ali Earthquake from InSAR Observations and Earthquake Rupture Model

In this study, we construct high-quality three-dimensional coseismic surface deformation field of the 2007 Ali earthquake using ascending and descending SAR data acquired from Envisat sate-llite with constraint of earthquake rupture model. Firstly, we use two-pass differential interferometry to generate line-of-sight coseismic surface deformation field of the earthquake from two pairs of SAR images. Then, with constraint of three components of displacement derived from the earthquake rupture model, we obtain the high-quality three-dimensional coseismic surface deformation field using Helmert variance component estimation method. The results show that the subsidence caused by the event is about 4.7 cm in the epicenter, where east-west displacement is small and the epicentral area is under north-south compression. We also calculate quasi east-west and quasi north-south displacements only with InSAR observations, whose patterns of deformation distribution are consistent with the results constrained by USGS earthquake rupture model. Finally, the characteristics of the three-dimensional deformation field indicate that the event is dominated by normal motion with slightly right-lateral strike-slip component.