阳高-天镇断裂晚第四纪活动特征及滑动速率  

THE LATE QUATERNARY ACTIVITY FEATURES AND SLIP RATE OF THE YANGGAO-TIANZHEN FAULT

作　　者：罗全星 李传友[1] 任光雪 李新男[1] 马字发 董金元 LUO Quan-xing;LI Chuan-you;REN Guang-xue;LI Xin-nan;MA Zi-fa;DONG Jin-yuan(State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China)

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029

出　　处：《地震地质》2020年第2期399-413,共15页Seismology and Geology

基　　金：国家重点研发计划项目(2017YFC1500101)资助。

摘　　要：山西地堑系北部的晋冀蒙盆岭构造区历史上无7级以上强震记录,但该区地处多个Ⅱ级活动地块的接合部位,具有孕育强震的构造条件,对其开展活动构造研究对区内的地震危险性评价工作具有重要意义。文中以晋冀蒙盆岭构造区内研究相对薄弱的阳高-天镇断裂为对象,基于遥感影像解译、野外地质、构造地貌调查对其晚第四纪活动特征进行了研究,发现阳高-天镇断裂多沿基岩山体与盆地内沉积物之间的接触带展布,在局部断裂几何结构不规则处向盆地内部生长;第四纪以来断裂以正断运动为主,但其运动性质沿走向存在差异。NEE和NE向为纯正断性质,而NWW向以正断为主,兼具左旋走滑运动分量;对沿断裂断错的地质体、地貌面进行了位移测量和光释光定年工作,得到断裂晚更新世以来的滑动速率为0.12~0.20mm/a,对应的拉张速率约占山西地堑系北部地壳伸展速率的10%。The Shanxi Graben System is one of the intracontinental graben systems developed around the Ordos Block in North China since the Cenozoic,and it provides a unique natural laboratory for studying the long-term tectonic history of active intracontinental normal faults in an extensional environment.Comparing with the dense strong earthquakes in its central part,no strong earthquakes with magnitudes over 7 have been recorded historically in the Jin-Ji-Meng Basin-and-Range Province of the northern Shanxi Graben System.However,this area is located at the conjunction area of several active-tectonic blocks(e.g.the Ordos,Yan Shan and North China Plain blocks),thus it has the tectonic conditions for strong earthquakes.Studying the active tectonics in the northern Shanxi Graben System will thus be of great significance to the seismic hazard assessment.Based on high-resolution remote sensing image interpretations and field investigations,combined with the UAV photogrammetry and OSL dating,we studied the late Quaternary activity and slip rate of the relatively poorly-researched Yanggao-Tianzhen Fault(YTF)in the Jin-Ji-Meng Basin-and-Range Province and got the followings:1)The YTF extends for more than 75km from Dashagou,Fengzhen,Inner Mongolia in the west to Yiqingpo,Tianzhen,Shanxi Province in the east.In most cases,the YTF lies in the contact zone between the bedrock mountain and the sediments in the basin,but the fault grows into the basin where the fault geometry is irregular.At the vicinity of the Erdun Village,Shijiudun Village,and Yulinkou Village,the faults are not only distributed at the basin-mountain boundary,we have also found evidence of late Quaternary fault activity in the alluvial fans that is far away from the basin-mountain boundary.The overall strike of the fault is N78°E,but the strike gradually changes from ENE to NE,then to NWW from the west to the east,with dips ranging from 30°to 80°.2)Based on field surveys of tectonic landforms and analysis of fault kinematics in outcrops,we have found that the se

关 键 词：阳高-天镇断裂 山西地堑系 晋冀蒙盆岭构造区 正断层 滑动速率 

分 类 号：P315.2[天文地球—地震学]