SEISMOLOGY AND GEOLOGY ›› 2008, Vol. 30 ›› Issue (3): 597-629.

• Brief Report • Previous Articles     Next Articles

THE MS8.0 WENCHUAN EARTHQUAKE SURFACE RUPTURES AND ITS SEISMOGENIC STRUCTURE

XU Xi-wei1, WEN Xue-ze2, YE Jian-qing3, MA Bao-qi4, CHEN Jie1, ZHOU Rong-jun2, HE Hong-lin1, TIAN Qin-jian5, HE Yu-lin2, WANG Zhi-cai6, SUN Zhao-min6, FENG Xi-jie7, YU Gui-hua1, CHEN Li-chun1, CHEN Gui-hua1, YU Shen-e4, RAN Yong-kang1, LI Xi-guang8, LI Chen-xia1, AN Yan-fen1   

  1. 1. National Center for Active Fault Studies, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2. Earthquake Administration of Sichuan Province, Chengdu 610041, China;
    3. Earthquake Administration of Zhejiang Province, Hangzhou 310013, China;
    4. Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China;
    5. China Center for Earthquake Disaster Prevention, Beijing 100029, China;
    6. Earthquake Administration of Shandong Province, Jinan 250014, China;
    7. Earthquake Administration of Shaanxi Province, Xi'an 710068, China;
    8. Earthquake Administration of Guangxi Zhuang Autonomous Region, Nanning, 530022, China
  • Received:2008-07-28 Revised:2008-08-04 Online:2008-09-18 Published:2009-11-27

汶川MS8.0地震地表破裂带及其发震构造

徐锡伟1, 闻学泽2, 叶建青3, 马保起4, 陈杰1, 周荣军2, 何宏林1, 田勤俭5, 何玉林2, 王志才6, 孙昭民6, 冯希杰7, 于贵华1, 陈立春1, 陈桂华1, 于慎鄂4, 冉勇康1, 李细光8, 李陈侠1, 安艳芬1   

  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. 四川省地震局, 成都, 610041;
    3. 浙江省地震局, 杭州, 310013;
    4. 中国地震局地壳应力研究所, 北京, 100085;
    5. 中国地震灾害防御中心, 北京, 100029;
    6. 山东省地震局, 济南, 250014;
    7. 陕西省地震局, 西安, 710068;
    8. 广西壮族自治区地震局, 南宁, 530022
  • 作者简介:徐锡伟,男,1962年生,1983年毕业于成都地质学院,1989年毕业于中国科技大学研究生院(国家地震局地质研究所),获得博士学位,研究员,现主要从事活动构造学及其在减轻地震灾害中的应用,电话:010-62009025,E-mail:xiweixu@vip.sins.com.
  • 基金资助:
    国家自然科学基金(40841007);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

Abstract: Field investigations show that the MS8.0 Wenchuan earthquake of 12th May 2008 ruptured two NW-dipping imbricate reverse faults along the Longmenshan Fault zone at the eastern margin of the Tibetan Plateau.This earthquake generated a 240km long surface rupture along the Beichuan-Yingxiu Fault characterized by right-lateral oblique faulting and a 90km long surface rupture along the Guanxian-Jiangyou Fault characterized by dip-slip reverse faulting.Maximum vertical and horizontal dispacements of 6.2m and 4.9m,respectively,were observed along the Beichuan-Yingxiu Fault,whereas a maximum vertical displacement of 3.5m occurred along the Guanxian-jiangyou Fault.This co-seismic surface rupture pattern,involving multiple structures,is among the most complicated of recent great earthquakes.Its surface rupture length is the longest among the co-seismic surface rupture zones for reverse faulting events ever reported.Aftershocks recorded by local network clearly outline the hanging wall of the Beichuan-Yingxiu Fault and indicate that the fault dips about 47? to the west.Industry seismic lines,in addition to surface ruptures and aftershocks,allow us to build a 3D model for the rupture geometry that shows crustal shortening is the dominant process along the Longmen Shan to accommodate long-term deformation.Oblique thrusting accomplished by the earthquake indicates that the east-southeastward extrusion of Tibet Plateau accommodates,in part,the continuing penetration of the Indian plate into the Eurasian plate,and this extrusion is transformed at the eastern margin of the Tibetan Plateau into crustal thickening and shortening along the Longmenshan Fault zone that is responsible for the growth of high topography in the region.

Key words: MS8.0 Wenchuan earthquake, earthquake surface rupture zone, 3D model for seismogenic fault geometry, Tibetan Plateau, Longmenshan Fault zone

摘要: 震后应急野外考察表明,2008年5月12日汶川MS8.0地震在青藏高原东缘龙门山推覆构造带上同时使北川-映秀断裂和灌县-江油断裂两条倾向NW的叠瓦状逆断层发生地表破裂。其中,沿北川-映秀断裂展布的地表破裂带长约240km,以兼有右旋走滑分量的逆断层型破裂为主,最大垂直位移6.2m,最大右旋走滑位移4.9m;沿灌县-江油断裂连续展布的地表破裂带长约72km,最长可达90km,为典型的纯逆断层型地表破裂,最大垂直位移3.5m;另外,在上述两条地表破裂带西部还发育着1条NW向带有逆冲垂直分量、左旋走滑性质的小鱼洞地表破裂带,长约6km。这一地表破裂样式是近期发生的特大地震中结构最复杂的一次逆断层型地表破裂,地表破裂的长度也最长。利用已有的石油地震剖面,结合余震分布和地表破裂带特征等资料构建的三维发震构造模型表明,龙门山推覆构造带现今和第四纪时期以地壳缩短为主,斜滑逆冲型地震表明青藏高原中东部的水平运动在华南地块与巴颜喀拉地块之间的龙门山推覆构造带上转化为地壳的缩短和隆升。

关键词: 汶川MS8.0地震, 地震地表破裂带, 三维发震构造模型, 青藏高原, 龙门山推覆构造带

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