海原-六盘山弧型断裂及其附近最新构造变形演化分析

RESEARCH ON LATE TECTONIC DEFORMATION EVOLVEMENT OF HUAIYUAN-LIUPANSHAN ARC FAULT AND ITS SURROUNDING AREA

利用两时段GPS速度场,用三维非线性有限元方法研究了海原-六盘山弧型断裂带及其附近最新构造变形演化特征。研究得到：1）海原-六盘山断裂带整体表现为左旋运动,海原断裂带左旋活动速率在（2~5.5）mm/a之间,六盘山断裂左旋活动速率约为1.0 mm/a;2）海原断裂带与六盘山断裂带的交接处目前处于强闭锁状态,亦是运动变形差异相对强烈、应变能积累较快的区段,存在强震孕震背景。

By using three-dimension nonlinear dynamic finite method and GPS velocity fields in two time periods,the late tectonic deformation features of Haiyuan-Liupanshan arc fault and its Surrounding Area were studied.The following results are obtained.1） Haiyuan-Liupanshan fault is of left lateral slip in whole but they are different in the two sections that the left lateral slip rate of Haiyuan fault is 2-5.5 mm/a and Liupanshan fault about 1.0 mm/a.2） At present,the junction segment of Haiyuan fault with Liupanshan fault is in strong locking state,where the moving deformation difference is relatively strong and strain engery accumulate rapidly.As a result,the strong seismogenic background may exist in this area.