1765年甘肃卓尼—康乐地震考证与发震构造探讨  

Textual Research on the 1765 Zhuoni-Kangle Earthquake in Gansu Province and Its Causative Structure

作　　者：王维桐 袁道阳 雷中生[1] 张波[1,3] WANG Weitong;YUAN Daoyang;LEI Zhongsheng;ZHANG Bo(Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, Gansu, China;School of Earth Sciences, Lanzhou University, Lanzhou 730000, Gansu, China;Lanzhou National Observatory of Geophysics, Lanzhou 730000,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]兰州大学地质科学与矿产资源学院,甘肃兰州730000 [3]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》2020年第3期714-720,758,共8页China Earthquake Engineering Journal

基　　金：中国地震科学实验场项目(2017CESE0102);国家自然科学基金(41572197,41602225);第二次青藏高原综合科学考察(SQ2019QZKK 2801);国家自然科学基金国际(地区)合作与交流项目(41661134011)。

摘　　要：根据历史地震资料考证、现场考察与综合分析,1765年5月1日发生在临洮南的一次中强破坏性地震其极震区位于卓尼、康乐交界的洮河连麓盆地附近的柳林、宗石一带,其名称应修改为卓尼—康乐地震,震级约51/2~6级,震中烈度可达Ⅷ度,极震区长轴方向大致与该区西秦岭北缘断裂带西段的锅麻滩断裂段东端相吻合。根据野外实地调查,锅麻滩断裂在极震区附近存在新活动的地质地貌现象,出露的断层剖面揭示出以左旋走滑为主兼具向北倾的正断特征,宏观地貌上沿断裂保留有断层陡坎、冲沟左旋位错等地貌标志。结合该区域构造应力场分析,本次卓尼—康乐地震发生在锅麻滩断裂段与漳县—黄香沟断裂段之间的左阶拉分区,是受区域应力影响引起断裂带在交汇部位与端点处应力集中所致。综合分析认为,锅麻滩断裂带东端是此次地震的发震构造。According to a textual research on historical materials,the Zhuoni-Kangle earthquake on May 1,1765,occurred around Liulin and Zongshi villages near the Taohe River.It had a magnitude of about 6 and an epicenter intensity of eight.The long axis direction of the extreme seismic area was roughly consistent with the eastern segment of the Guomatan fault.A field investigation revealed that the Guomatan fault had a new activity near the extreme seismic zone,which was characterized by a left-lateral strike-slip fault with normal components.The fault dipped NE,and geomorphological signs such as fault ridges and gully dislocations were preserved along the fault.The analysis of the tectonic stress field in this area also indicated that the Zhuoni-Kangle earthquake occurred in the sinistral step between the Guomatan fault and the Zhangxian-Huangxianggou fault,which is caused by the stress concentration at the intersection and end points of the fault zone.Our comprehensive analysis suggested that the Guomatan fault served as the seismogenic structure of the Zhuoni-Kangle earthquake.

关 键 词：卓尼—康乐地震 历史地震考证 发震构造 西秦岭北缘断裂带 

分 类 号：P316[天文地球—地震学]