文章摘要

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Title:: The Holocene Activity Evidence of Paleo-earthquakes in the Northwestern Segment of the Deqin-Zhongdian Fault

作者:: 常玉巧¹; 李西²; 周青云¹; 白仙富¹; 冉华¹; 罗伟东¹; (1.云南省地震局,云南昆明 650224; 2.云南大学地球科学学院,云南昆明 650500)

Author(s):: CHANG Yuqiao¹; LI Xi²; ZHOU Qingyun¹; BAI Xianfu¹; RAN Hua¹; LUO Weidong¹; (1.Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)(2.School of Earth Science,Yunnan University,Kunming 650500,Yunnan,China)

Keywords:: the Deqin-Zhongdian Fault; the Gongka Lake trench; paleo-earthquake; Holocene activity; the Yunnan-Tibet Railway Project

摘要:: 在高分辨率遥感解译基础上,沿德钦—中甸断裂开展野外地质地貌调查和断错地貌无人机测绘等工作,并在断裂北西段德钦县北的贡卡湖附近线性断层槽谷内开挖了一个大型探槽,探槽剖面揭露出多条断裂信息。结合多个¹⁴C样品年代学分析发现,断裂明确错断了全新世地层,且揭露出一次明确地震事件E1:(1 140±30)—(1 010±30)a BP,一次可能事件E2:(570±30)—(410±30)a BP。结果表明:德钦—中甸断裂北西段全新世以来有过活动,水平方向以右旋走滑为主,垂向上具有倾滑分量,总体表现为正走滑特征。

Abstract:: Based on the high-resolution remote sensing interpretation and a detailed field geological and geomorphological survey,we excavate a trench in the linear fault trough beside the Gongka Lake to reveal the direct evidence of the Holocene activity and paleo-earthquake.The trench,which is perpendicular to the fault trace,obviously manifests positive dip-slip faults and shows that the Deqin-Zhongdian Fault has dislocated the Holocene stratum.Through paleoseismic analysis of the relationship between the fault and stratigraphic ages,cracks and colluvial,and the age of sedimentation determined by means of AMS-¹⁴C dating,two palaeo-seismic events are identified.They are respectively between(1 140±30)-( 1 010±30)a BP and(570±30)-(410±30)a BP.The segment in the northwest of the Deqin-Zhongdian Fault was an active fault in Holocene and was characterized as positive dip-slip.

备注/Memo:: 收稿日期:2022-03-19.
基金项目:云南省地震局科技专项(2019ZX03); 上海佘山地球物理国家野外科学观测研究站开放基金(SSOP202101).
第一作者简介:常玉巧(1988-),工程师,主要从事活动构造、古地震及构造地貌研究.E-mail:349797655@qq.com.
通讯作者简介:李西(1975-),高级工程师,主要从事构造地质学、活动构造、古地震、GIS应用及开发、震害预测和评估等研究.E-mail:179298308@qq.com.