联合GPS与重力资料反演分析川滇地区现今地壳形变
Contemporary Crustal Deformation in Sichuan-Yunnan Region from GPS and Gravity Data
-
摘要: 联合GPS与重力数据,反演给出了川滇地区(96°~106°E,20°~36°N)的活动块体运动速度和主要活动断裂的错动速率。受青藏块体的北东向推挤和青藏高原隆升引起的重力势能作用,川滇地区围绕着喜马拉雅东构造作顺时针旋转运动,造成川滇地区东侧断裂作左旋走滑运动,而西侧断裂以右旋走滑为主。鲜水河-夏宁河-则木河-小江断裂是区内最活跃的断裂带,其左旋走滑速率分别为12.1±0.6 mm/a,9.0±1.2mm/a,6.4±1.0 mm/a,6.0±1.2 mm/a和8.3±0.5 mm/a。龙行山断裂具有2.6±1.1 mm/a的右旋走滑和1.3±1.2 mm/a的挤压速率。反演结果表明,区内的地壳运动模式更趋向于“连续变形”假说。Abstract: High precision GPS horizontal velocities and gravity data were used to estimate the crustal motion and fault slip rate in Sichuan-Yunnan region(96°-106°E,20°-36°N).Due to the influence of India-Tibet block's east-northward extrusion,and the gravitational buoyancy force associated with the sharp topographic gradient across the region,the first-order features of crustal deformation are the prominent clockwise rotation around East Himalaya Syntax(EHS),and leads left-slip motion along the Xianshuihe-Xiaojiang fault system(east boundary) and right-slip motion along the Jinshajiang-Honghe fault system(west boundary).The Xianshuihe-Anninghe-Zemuhe-Xaiojiang fault system is the most active left-lateral fault in the region,with a rate of 12.1±0.6 mm/a,9.0±1.2 mm/a,6.4±1.0 mm/a,6.0±1.2 mm/a and 9.0±1.2 mm/a respectively.The Longmenshan fault system is with a rate of 2.6±1.1 mm/a right-lateral slip,and 1.3±1.2 mm/a extrude.As a result,the pattern of crustal deformation in the region supports the continuous deformation hypothesis.
下载:
