Regional crustal stability assessment of the eastern margin of Tibetan Plateau
YAO Xin;LI Lingjing;ZHANG Yongshuang;GUO Changbao;ZHOU Nengjuan;Key Laboratory of Neotectonic Movement & Geohazard/Ministry of Land and Resources/Institute of Geomechanics,Chinese Academy of Geological Sciences;College of Engineering and Technology,China University of Geosciences;
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.