小江断裂带宜良盆地西缘断裂晚第四纪活动的地质地貌证据  

The Late Quaternary Activity of the Fault along the Western Margin of the Yiliang Basin of the Xiaojiang Fault Zone

作　　者：常玉巧[1] 陈立春 李西[1] 周青云[1] CHANG Yuqiao;CHEN Lichun;LI Xi;ZHOU Qingyun(Yunnan Earthquake Agency,Kunming 650224,Yunnan,China;College of Earth Sciences,Guilin University of Technology,Guilin 541006,Guangxi,China)

机构地区：[1]云南省地震局,云南昆明650224 [2]桂林理工大学地球科学学院,广西桂林541006

出　　处：《地震研究》2021年第2期152-161,共10页Journal of Seismological Research

基　　金：国家自然科学基金项目(41372218);云南省地震局地震科技专项(2019ZX03)共同资助。

摘　　要：据历史资料记载,云南宜良地区曾于公元1500年发生过一次M>7地震,该地震发生在小江断裂带上,但对其具体发震断层及其地表破裂分布的确定,仍存有较大分歧。在高分辨率遥感影像解译基础上,沿宜良盆地西缘断裂进行了翔实的地质地貌调查,获得了该断裂晚第四纪活动的一些地质地貌证据。店房探槽和打挂村探槽组开挖结果揭示:宜良盆地西缘断裂断错了全新世地层,最新一次活动断错了(2460±30)a BP的地层。结合断错地貌和地震破坏记录的分析,其最新事件可能对应于1500年宜良地震。The Xiaojiang Fault Zone forms the southeastern boundary of the Sichuan-Yunnan Block.As one of the most seismically active zones in Yunnan Province, many historical strong earthquakes(M>7),such as the 1833 M8 Songming earthquake, occurred in it.Along the western margin of the Yiliang Basin and in the eastern branch of the Xiaojiang Fault Zone, there is a secondary fault zone which is composed of the Xiaoxinjie-Yiliang Fault, the Yiliang-Xujiadu Fault, and the Majie-Nanyangjie Fault.The M>7 Yiliang earthquake in 1500 had produced a long surface rupture distributing discontinuously along the western margin of the Yiliang Basin.The remote sensing image shows that the secondary fault zone has a remarkable linear feature.There are a lot of dislocation landforms such as fault trough and fault scarps along its strike.Based on interpretation of high-resolution remote sensing images, and through detailed geological and geomorphological investigation, we obtained geological evidences of the late Quaternary activity of the secondary fault.The trench in Dianfang village revealed that the secondary fault had dislocated the Holocene stratum and behaved as a normal fault.Two trenches in Dagua village reveal that the 2460 a BP strata had been dislocated by the fault along the western margin of the Yiliang Basin.We analyzed dislocation landform and the historical recordings, and found that the Yiliang earthquake in 1500 may be the latest event.

关 键 词：小江断裂带 宜良盆地 探槽 1500年宜良地震 

分 类 号：P315.21[天文地球—地震学]