Regional crustal stability assessment of the eastern margin of Tibetan Plateau

Eastern margin of the Tibetan Plateau is a sharpen change zone of geomorphology and geology, with complex and strong Neotectonic movement, breeding environment of numerous earthquakes and geo-hazards occurred largely. It is of great significance to carry out Regional Crustal Stability Assessment (RCSA). Using RCSA combined geo-mechanics and continental dynamics theory, this paper selected four types data, deep geophysical fields, regional tectonic deformation, regional tectonic stress fields and seismic activity, as internal dynamic factors, geo-hazard combining with topography, rainfall and river erosion as the external factors, lithology and affecting strip of active fault as the medium factors, then to carry out the RCSA. The results show that: (1) it is an effective means to improve the assessment accuracy that using geological elements gradient reflects the internal dynamic action and using comprehensive analysis of geological environment reflects external dynamic action;（2）evaluation results show that the study area can be divided into eight one-class zonations by tectonic characteristics significantly different, 75 secondary zonations by comprehensive factors differences vary greatly, and 653 three-class zonations by outside dynamic conditions;（3）in brief, fault belts near and/or in the tectonic skeleton, composed mainly with Longmenshan fault, Xianshuihe fault, Anninghe fault, are the worst, followed by the west, the east is best, the north relatively complete, and the southern breaking and complex.