地震地质 ›› 2008, Vol. 30 ›› Issue (3): 723-738.

• 研究论文 • 上一篇    下一篇

2008年汶川MS8.0地震地表破裂变形定量分析——北川-映秀断裂地表破裂带

陈桂华1, 徐锡伟1, 郑荣章1, 于贵华1, 李峰1,2, 李陈侠1, 闻学泽3, 何玉林3, 叶友青3, 陈献程1, 王志才4   

  1. 1. 中国地震局地质研究所, 国家地震活动断层研究中心, 北京, 100029;
    2. 中国地震局地质研究所, 国家地震活动断层研究中心, 北京, 100029;
    3. 四川省地震局, 成都, 610041;
    4. 山东省地震局, 济南, 250014
  • 收稿日期:2008-07-20 修回日期:2008-07-30 出版日期:2008-09-18 发布日期:2009-11-27
  • 作者简介:陈桂华,男,1977年生,1999年毕业于中国地质大学(武汉)地球科学学院地球科学基地班,2006年在中国地震局地质研究所获得博士学位,助理研究员,现主要从事活动构造、构造地貌以及3S技术在活动构造中的应用研究,电话:010-62009170,E-mail:gh_chen@163.com.
  • 基金资助:
    中国地震局地质研究所基本科研业务专项(DFIGCEA060712);国家重点基础研究发展计划项目(2004CB418401);中国地震局汶川8.0级地震应急科学考察项目共同资助

QUANTITATIVE ANALYSIS OF THE CO-SEISMIC SURFACE RUPTURE OF THE 2008 WENCHUAN EARTHQUAKE, SICHUAN, CHINA ALONG THE BEICHUAN-YINGXIU FAULT

CHEN Gui-hua1, XU Xi-wei1, ZHENG Rong-zhang1, YU Gui-hua1, LI Feng1,2, LI Chen-xia1, WEN Xue-ze3, HE Yu-lin3, YE You-qing3, CHEN Xian-cheng1, WANG Zhi-cai4   

  1. 1. National Center for Active Fault Studies, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2. China Earthquake Disaster Prevention Center, Beijing 100029, China;
    3. Earthquake Administration of Sichuan Province, Chengdu 610041, China;
    4. Earthquake Administration of Shandong Province, Jinan 250014, China
  • Received:2008-07-20 Revised:2008-07-30 Online:2008-09-18 Published:2009-11-27

摘要: 2008年汶川MS8.0地震在北川-映秀断裂产生了长达240km的同震地表破裂。通过详细的测量、基于测量标志与断裂变形的几何关系对数据的分析,给出了观测点的断裂同震地表变形的垂直位移、倾向水平缩短、走向滑动、断层上盘水平运动方向等参数。结果显示,断裂同震变形分布的空间变化很大,目前获得的最大水平位移位于虹口乡深溪沟,为4.98m,同时也是最大右旋走滑位移点,走滑量4.5m,而目前获得的最大垂直位移在其东北的支沟,为5.7~6.7m。NE向断裂水平位移多为1~2m,垂直位移多为3m左右,而小鱼洞-草坝分支断裂水平位移和垂直位移都更小,只有0.5~1.5m。擂鼓镇附近的数据则反映与断裂相关的巨型滑坡可能将重力变形叠加到构造变形中。由断层水平缩短和垂直位移计算的断层倾角表明,北川-映秀断裂是浅部陡倾的具有走滑分量的逆断层。

关键词: 汶川MS8.0地震, 北川-映秀断裂, 同震地表变形, 测量

Abstract: A 240km-long co-seismic surface rupture was produced along the Beichuan-Yingxiu Fault during the 2008 Wenchuan earthquake.We made a detailed survey at representative sites along the surface rupture and analyzed the data based on the geometry between the benchmark and deformation.The co-seismic vertical slip,horizontal dip-slip shortening,strike slip and moving direction of the hanging-wall were calculated based on the survey data of these sites.Results show that the spatial distribution of the co-seismic deformation of the fault varies a lot along the fault.The maximal horizontal slip,as we got till now,is located in the Shenxigou site of Hongkou with a value of 4.98m,and the maximal strike slip is also located in the same site with a value of 4.5m.The maximal vertical displacement is located to the northeast of Shenxigou with a value of 5.7~6.7m.The average horizontal slip for the NE trending fault is 1~2m,and the average vertical slip is 3m.But horizontal and vertical slip for the NW-trending branch from Xiaoyudong to Caoba is only 0.5~1.5m.The data from Leigu town show that the gravity deformation resulting from the fault-related landslide was perhaps superimposed on the tectonic one.The dip angles of the fault at the surveyed sites calculated from the horizontal shortening and vertical displacement indicate that the Beichuan-Yingxiu Fault is a steep dipping reverse fault with some strike-slip.From the comparison between field results and geophysical inversion,we believe that the spatial distribution of co-seismic fault-slip is related to the barriers and rupture process along the fault plane.

Key words: MS8.0 Wenchuan earthquake, the Beichuan-Yingxiu Fault, co-seismic surface rupture, deformation survey

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