甘加盆地西缘断裂带发现新活动证据  

Evidence of new activities along the western margin fault zone of the Ganjia Basin

作　　者：陆诗铭 王爱国[1,2] 文亚猛 张波 LU Shiming;WANG Aiguo;WEN Yameng;ZHANG BO(Lanzhou Institute of Seismology, CEA, Lanzhou 73000, Gansu, China;Gansu Lanzhou Geophysics National Observation and Research Station, Lanzhou 73000, Gansu, China)

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]甘肃兰州地球物理国家野外科学观测研究站,甘肃兰州730000

出　　处：《地震工程学报》2021年第5期1045-1053,共9页China Earthquake Engineering Journal

基　　金：中国地震局地震预测研究所基本科研业务专项(2020IESLZ02)。

摘　　要：甘加盆地位于西秦岭北缘断裂带西端,盆地西缘发育了三条近南北向的断层(东支、中支、西支),表现为西高东低的弧形地貌阶梯带。基于高分辨率卫星遥感影像解译、地质地貌调查、UAV航拍测量、剖面清理与14C测年等工作,对甘加盆地西缘断裂带进行综合研究,发现该断裂带第四纪晚期有新活动。断层新活动在地貌上表现为不同级别的断层陡坎、阶地与洪积台地断错以及冲沟与阶地右旋等特征。断层剖面与擦痕揭示,该断裂带具右旋逆冲性质,断层断错最新地层为全新统。根据测量与测年数据,初步估算甘加盆地西缘断裂带西支全新世中期以来的平均水平右旋滑动速率为0.89 mm/a,平均垂直滑动速率为0.30 mm/a。In the west margin of the Ganjia Basin,which is located at the western end of the northern margin fault of West Qinling fault,three nearly SN-trending faults(east branch,middle branch,and west branch)were developed,showing an arc landform ladder with high west and low east.Based on the interpretation of high-resolution satellite remote sensing images,geological and geomorphological survey,UAV aerial measurement,and profile cleaning and 14C dating,evidences of new activities in late Quaternary were found along the west margin fault zone of the Ganjia Basin.The new fault activities were characterized by different levels of fault scarps,faulted terraces and diluvial platforms,and right-lateral gullies and terraces.The profile and scratch of faults revealed that the western margin fault zone of the Ganjia Basin has the property of dextral thrust,and the latest stratum of fault dislocation is Holocene.According to the UAV measurement and dating data,the average horizontal right-lateral slip rate of the west branch of the west margin fault of Ganjia Basin since the middle Holocene is estimated as 0.89 mm/a,while the average vertical slip rate is 0.30 mm/a.

关 键 词：甘加盆地西缘断裂带 断层新活动特征 西秦岭北缘断裂 右旋逆冲 

分 类 号：P315.2[天文地球—地震学]