The arc rotational-shear active tectonic system on the southeastern margin of Tibetan Plateau and its dynamic characteristics and mechanism

On the basis of previous data on active faults in combination with information of active faults on the southeast margin of the Tibetan Plateau obtained by the authors based on remote sensing and ground survey, the authors hold that the main active fault zones constitute a large convex for the east arc-shaped tectonic system called Sichuan-Yunnan arc-shaped rotational-shear active tectonic system. The related factors mainly include the boundary forces between different blocks, the existing structural features and crustal structure, lithospheric material composition and its physical properties and deep thermal state, as well as gravitational potential energy between different lithospheric blocks. Among these factors, lithosphere structure and physical properties boundary force as well as the boundary forces resulting from right lateral shear between India plate and Yangtze plate and the eastward extrusion of the Tibetan Plateau might have been the most important factors that controlled and affected clockwise rotation of Sichuan-Yunnan blocks and produced shear and extension deformation around the EHS.