元谋断裂带晚第四纪活动性与地震地质灾害的关系  

Relationship Between Activity of the Yuanmou Fault and Earthquake-induced Geological Disaster During the Late Quaternary

作　　者：卢海峰 LU Haifeng(Key Laboratory of Neotectonic Movement and Geohazard,Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Research Center of Neotectonism and Crustal Stability,China Geological Survey,Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Institute of Crustal Dynamics,China Earthquake Administration,Beijing 100085,China)

机构地区：[1]中国地质科学院地质力学研究所新构造运动与地质灾害实验室,北京100081 [2]中国地质科学院地质力学研究所中国地质调查局新构造与地壳稳定性研究中心,北京100081 [3]中国地震局地壳应力研究所,北京100085

出　　处：《大地构造与成矿学》2021年第3期478-491,共14页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41002074);国家公益性重大专项(201108001);中国地质调查局项目(DD20190018)联合资助。

摘　　要：活动构造与地震地质方面研究揭示,中国南北地震带西南边缘的元谋断裂带晚第四纪活动特征总体表现为北强南弱,活动性质由北段(江边以北)全新世伸展性左行走滑、向南逐步过渡为全新世早中期的剪切性左行走滑、至南段(罗川以南段)晚更新世挤压式整体抬升和全新世活动不明显特征。综合地震地质灾害发育特点的调查结果表明,元谋断裂带北段震害特点表现为地表形变、新滑坡体产生和老滑坡体复活、崩塌及地裂缝发育、泥石流和砂土液化等。断裂带中段(江边‒罗川段)控制的盆地边缘主要发育了大面积洪积扇体,在水流作用下易引起泥石流;此外,老滑坡体复活、局部崩塌、软土变形和砂脉等现象也较发育。南段(罗川以南段)灾害则以沿断层破碎带的塌方、老滑坡体复活、局部泥石流等为主。元谋断裂带的晚第四纪活动性质、地震灾害类型及分布特征表明,该断裂带晚第四纪活动性分段特征明显影响着构造带上及其附近的地震地质灾害类型、分布特征及未来地震活动趋势,断裂北段更易诱发中‒强震,且该构造带晚更新世以来的伸展‒剪切变形作用和地震活动均具有向南扩展的趋势。认识元谋断裂带晚第四纪变形特征与地震地质灾害发育特点对于深入探索青藏高原东南缘新构造期以来的构造变动、机理与引起的震害响应关系,以及进一步开展该区工程场地选址和地震地质灾害防治等工作意义重大。The Yuanmou Fault is an important active fault,which is located at the southwest part of the south-north-trending earthquake belt.Field investigations and geomorphic analyses showed that the Yuanmou fault is characterized by the transtensional left-lateral strike-slipping in the north,the simple shearing at the central part and the overall uplift in the south due to the compressional deformation.The variable activities of different sections of the Yuanmou Fault revealed the southward decline of active intensity since the late Pleistocene.Thus,the earthquake-related geological disasters in these three sections also show different deformational types with the birth and recurrence of landslides,collapse and ground fracture in the north,debris flow,recurrence of paleolandslides,local collapse and liquefaction in the central part,and collapse along the fault damage zone and local debris flow in the south.The late Quaternary activities and earthquake-induced disasters of the Yuanmou Fault suggested that the segmentation may control significantly the hazard types,distribution pattern and seismic risk in the future.The northern segment is prone to trigger large-and moderate earthquakes,and gradually propagate southward.The findings concerning the late Quaternary seismic activities and geologic hazards of the Yuanmou Fault would throw light on the understanding of the tectonic movement,earthquake mechanism and geomorphic response of the active tectonics in the southeastern Tibetan Plateau,and contribute to the engineering site selection and disaster prevention.

关 键 词：元谋断裂带 晚第四纪活动性 地震地质灾害 地震活动趋势 场地选址和灾害防治 

分 类 号：P546[天文地球—构造地质学] P694[天文地球—地质学]