2008年10月当雄 M W 6.3级地震断层参数的InSAR反演及其构造意义

A Mw6.3 earthquake occurred in Damxung, Tibet, on October 6th, 2008. We determined the fault parameters using a descending coseismic interferogram from ENVISAT ASAR images. In addition， we examined the uncertainties in the InSAR-derived source parameters using the variance-covariance matrix of InSAR data points estimated with a 1-D semivariogram function. The inverted results showed that the earthquake occurred on a secondary fault in the eastern margin of the Yangyi basin, with a strike of 178°, a dip of 58° and dipping to west, which was normal faulting with a little of right-lateral strike slipping. It also appeared that the impact of the measurement errors on the uncertainties in InSAR derived source parameters was limited. This earthquake led to a subsidence of at least 30 cm at the epicenter, implying the Yangyi basin in the northern Yadong-Gulu Rift Belt was subsiding probably.