Discussion of Crustal Flow Beneath the Eastern Tibetan Plateau and Mechanism of the Wenchuan Earthquake

The crustal deformation of eastern Tibetan Plateau using GPS is analysed.Then,the distri-bution and movement of viscous flows in the mid-lower crust of eastern Tibetan is discussed in termsof MT data and seismic tomography.A new viscous flows model is put forward,showing that thereare two large-scale crustal flow channels and many unevenly distributed viscous flows in eastern Tibet-an Plateau.Most viscous flows in the Bayan Har block may turn to south or north along the Longmen Mountain fault when meeting the fault,while limited viscous flows are depositing and upwelling near-by the Longmen Mountain fault,which has caused channel blockage,eventually triggeing the Wen-chuan earthquake.