青海达日断裂中段晚第四纪活动性与1947年M73/4地震地表破裂带再研究  

LATE QUATERNARY ACTIVITY OF THE CENTRAL SEGMENT OF THE DARI FAULT AND RESTUDY OF THE SURFACE RUPTURE ZONE OF THE 1947 M73/4 DARI EARTHQUAKE,QINGHAI PROVINCE

作　　者：梁明剑[1] 杨耀[1] 杜方[1] 宫悦[1] 孙玮[1] 赵敏[1] 何强[1] LIANG Ming-jian;YANG Yao;DU Fang;GONG Yue;SUN Wei;ZHAO Min;HE Qiang(Sichuan Earthquake Agency,Chengdu 610041,China)

机构地区：[1]四川省地震局,成都610041

出　　处：《地震地质》2020年第3期703-714,共12页Seismology and Geology

基　　金：中国地震局地震科技星火计划项目(XH192305);中国地震科学实验场项目(2018CSES0209);“川滇地区强震孕育深部结构与动力环境研究”创新团队基金(201804)共同资助。

摘　　要：在该块体内部还存在一些规模巨大的断裂带,不仅具有晚第四纪活动性,而且具有孕育和发生强震的构造条件。达日断裂是巴颜喀拉块体内一条规模巨大的左旋走滑断裂,曾发生过1947年达日M73/4大地震。文中基于高分辨率遥感影像解译和地震地质调查,详细研究了达日断裂中段的晚第四纪新活动性和1947年达日大地震的地表破裂带。达日断裂中段晚第四纪活动的行迹尤为显著,1947年达日地震地表破裂带的SE端始于达日县莫坝乡隆根,向NW延伸至建设乡依龙沟脑NW侧,长约70km。地震地表破裂带主要表现为地震坎、地震鼓包与陷坑、地震滑坡、线性的碎裂基岩出露等地貌迹象,并使一系列冲沟被同步左旋位错2~4m。Bayan Hara Block is one of the most representative active blocks resulting from the lateral extrusion of Tibet Plateau since the Cenozoic.Its southern and northern boundary faults are characterized by typical strike-slip shear deformation.Its eastern boundary is blocked by the Yangze block and its horizontal movement is transformed into the vertical movement of the Longmen Shan tectonic belt,leading to the uplift of the Longmen Shan Mountains and forming a grand geomorphic barrier on the eastern margin of the Tibet Plateau.A series of large earthquakes occurred along the boundary faults of the Bayan Hara Block in the past twenty years,which have attracted attention of many scholars.At present,the related studies of active tectonics on Bayan Hara Block are mainly concentrated on the boundary faults,such as Yushu-Ganzi-Xianshuihe Fault,East Kunlun Fault and Longmen Shan Fault.However,there are also some large faults inside the block,which not only have late Quaternary activity,but also have tectonic conditions to produce strong earthquake.These faults divide the Bayan Hara Block into some secondary blocks,and may play important roles in the kinematics and dynamics mechanism of the Bayan Hara Block,or even the eastern margin of the Tibet Plateau.The Dari Fault is one of the left-lateral strike-slip faults in the Bayan Hara Block.The Dari Fault starts at the eastern pass of the Kunlun Mountains,extends eastward through the south of Yalazela,Yeniugou and Keshoutan,the fault strike turns to NNE direction at Angcanggou,then turns to NE direction again at Moba town,Qinghai Province,and the fault ends near Nanmuda town,Sichuan Province,with a total length of more than 500 km.The fault has been considered to be a late Quaternary active fault and the 1947 M73/4 Dari earthquake was produced by its middle segment.But studies on the late Quaternary activity of the Dari Fault are still weak.The previous research mainly focused on the investigation of the surface rupture and damages of the 1947 M73/4 Dari earthquake.However,ther

关 键 词：达日断裂 晚第四纪新活动性 1947年达日地震 地震地表破裂 

分 类 号：P315.2[天文地球—地震学]