2014年新疆于田M_S7.3地震的地壳构造变形背景

Research on Crustal Tectonic Deformation Background of Xinjiang Yutian M_S7.3 Earthquake in 2014

利用2011~2013年的流动GNSS观测资料及处理结果,获得了2014年于田MS7.3地震区域水平形变场。结果显示：（1）于田MS7.3地震发生在构造活动较强烈的阿尔金断裂带西端,其两侧的形变差异运动为8~9 mm/a,左旋运动是差异运动的主要成份;（2）发震区域的主应变是全区最突出的区域,张压大小相对均等,主张方向为南东东—北西西;（3）该地震发生在左旋形变的高梯度带上,其北部的塔里木盆地为较弱的右旋形变,其南部约150 km以外几乎无旋形变;（4）地震发生的部位为面应变性质转变的过渡带,其西为面膨胀区,其东为面收缩区。

Using the flow GNSS observation data and its processing results from 2011 to 2013,we obtained the result of the horizontal deformation field of Yutian MS7. 3 earthquake in 2014 as follow s：（ 1） The Yutian MS7. 3earthquake occurred in the west end of Arkin fracture zone where the active structure is strong,the differential movement on both sides of Arkin fracture zone is about 8 mm / a and its main component is the left-lateral movement.（ 2） The principal strain in the epicenter area is the most prominent in the study area,the tensile strain is relatively equal to the compressive strain and the direction of main tensile strain is SEE-NWW.（ 3） The Yutian MS7. 3 earthquake occurred in the high gradient belt of the left-lateral deformation,the Tarim Basin in the north of it has weak right-lateral deformation and the area about 150 km away from the Basin in the south of it has little rotary deformation.（ 4） The epicenter was located at a transition zone of the property transition of plane strain,that is,the surface expansion area is gradually varied to the surface contraction area from the west to the east of the epicenter.