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| 2021年5月21日云南漾濞Ms6.4地震震害特征及成因 |
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熊伟1,2,3,4, 黄小龙4,5,6, 吴中海2,3,4, 张海军1, 史亚然1,2,3,4, 范讷1,2,3,4, 韩帅2,3,4
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1.中国地质大学(北京)地球科学与资源学院, 北京 100083;2.自然资源部活动构造与地质安全重点实验室, 北京 100081;3.中国地质调查局新构造与地壳稳定性研究中心, 北京 100081;4.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;5.长江三峡勘测研究院有限公司, 湖北 武汉 430074;6.长江勘测规划设计研究有限责任公司, 湖北 武汉 430010
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| 摘要: |
| 位于青藏高原东南缘的漾濞地区地质构造环境复杂,导致地震的发生与表现受多种因素共同控制。为明确漾濞6.4级地震的烈度分布特点、震害特征及其影响因素,采用走访、野外调查、统计分析等方法对其开展了研究。结果显示,漾濞6.4级地震的极震区烈度可达Ⅷ度,等震线椭圆体长轴呈NW向偏转,与地震序列的重定位及震源机制解结果一致,指示发震断层是呈NW—SE走向,倾向SW,具右旋走滑性质的草坪断裂。其中,Ⅷ度区在南东端发生了约30°的偏转,是受到断裂尾端拉张破裂效应的影响。Ⅶ度区等震线向断裂倾向相反方向突出,且烈度的整体范围比前人的调查结果小很多,可能与断裂两侧地形差异,物性差异、地震波的盆地聚焦效应与边缘效应有关,也与河谷盆地中松软的河谷沉积物、较高的地下水位、苍山高海拔产生的烈度放大效应的影响有关。在上述烈度区发育的震害主要是房屋的破坏与地震地质灾害,其中房屋的破坏较严重,地震地质灾害规模较小。地质灾害的类型主要为滑坡及地裂缝,调查分析发现其并没有表现出沿断层或极震区集中发育的特征,更多的是受地形、地表介质、地下水等因素的影响。 |
| 关键词: 漾濞地震 发震断裂 地震烈度 震害特征 青藏高原东南缘 |
| DOI：10.12097/j.issn.1671-2552.2022.08.012 |
| 分类号:P315.1;P315.9 |
| 基金项目:国家自然科学基金项目《金沙江石鼓-攀枝花段活断层作用及其触发巨型滑坡-堵江灾害链时空特征研究》(批准号:U2002211)、国家科技基础资源调查专项课题《块体边界带重要断裂活动性鉴定》(编号:2021FY1001104)、中国地质调查局项目《地表过程与系统演变地质调查》(编号:DD20221644) |
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| Damage characteristics and cause of Ms 6.4 earthquake in Yangbi, Yunnan Province on May 21, 2021 |
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XIONG Wei1,2,3,4, HUANG Xiaolong4,5,6, WU Zhonghai2,3,4, ZHANG Haijun1, SHI Yaran1,2,3,4, FAN Ne1,2,3,4, HAN Shuai2,3,4
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1.School of Earth Sciences and Resources, China University of Geosciences(Beijing), Beijing 100083, China;2.Key Laboratory of Active Tectonics and Geological Safety, Ministry of Natural Resources, Beijing 100081, China;3.Research Center for Neotectonics and Crustal Stability, China Geological Survey, Beijing 100081, China;4.Key Laboratory of Neotectonic Movement & Geohazard, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China;5.Three Gorges Geotechnical Consultants Co., Ltd., Wuhan 430074, Hubei, China;6.Changjiang Survey, Planning, Design and Research Co., Ltd., Wuhan 430010, Hubei, China
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| Abstract: |
| Yangbi area,located in the southeast margin of Qinghai-Tibet Plateau,is characterized by complex geological structure,which leads to the occurrence and behavior of earthquakes controlled by many factors.In order to clarify the intensity distribution characteristics,damage characteristics and influencing factors of Yangbi Ms 6.4 earthquake,the research work was carried out by means of interview,field investigation and statistical analysis.The results show that the intensity of the Yangbi Ms 6.4 earthquake in the extreme earthquake area can reach Ⅷ,and the major axis of the isoseismal ellipse deflects NW,which is consistent with the relocation of the earthquake sequence and the solution of focal mechanism,indicating that the seismogenic fault is a Caoping fault with NW-SE strike and SW dip and right-handed strike-slip property.Among them,the Ⅷ degree area deflects by about 30 at the southeast,which is affected by the tensile fracture effect at the tail end of the fault.The isoseismal line in the Ⅶ degree area is prominent in the opposite direction to the fracture tendency,and the overall range of intensity is much smaller than the previous survey results,which may be related to the difference of topography,physical properties on both sides of the fault,basin focusing effect and edge effect of seismic waves,as well as the influence of the intensity amplification effect caused by soft valley sediments,high groundwater level in the valley basin and high altitude of Cangshan Mountain.The earthquake damages developed in the above-mentioned intensity areas are mainly the destruction of houses and seismic geological disasters,in which the destruction of houses is more serious and the scale of seismic geological disasters is smaller.The types of geological disasters are mainly landslides and ground fissures.After investigation and analysis,it is found that they do not show the characteristics of concentrated development along faults or extreme earthquake areas,which are more affected by factors such as topography,surface media and groundwater. |
| Key words: Yangbi earthquake seismogenic fault seismic intensity characteristics of seismic damage southeasten Tibetan plateau |
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