地震地质 ›› 2011, Vol. 33 ›› Issue (3): 525-532.DOI: 10.3969/j.issn.0253-4967.2011.03.003

• 大地震研究 • 上一篇    下一篇

2010年玉树地震震前甘孜-玉树断裂形变场分析

王阎昭1, 王敏1, 沈正康2, 葛伟鹏1, 王康2, 王凡1, 孙建宝1   

  1. 1. 中国地震局地质研究所, 地震动力学国家重点实验室, 北京 100029;
    2. 北京大学地球与空间科学学院, 北京 100871
  • 收稿日期:2010-12-22 修回日期:2011-03-29 出版日期:2011-09-29 发布日期:2011-12-16
  • 作者简介:王阎昭,女,1981年生,2009年在中国地震局地质研究所获得固体地球物理学博士学位,助研,主要研究方向为GPS地壳形变、地震构造学与地球动力学,电话: 010-62009146,E-mail: wangyz 0513@gmail.com。
  • 基金资助:

    地震动力学国家重点实验室课题(LED2009A02)和中国地震局地质研究所基本科研业务专项(IGCEA1011)共同资助。

INTER-SEISMIC DEFORMATION FIELD OF THE GANZI-YUSHU FAULT BEFORE THE 2010 YUSHU EARTHQAUKE

WANG Yan-zhao1, WANG Min1, SHEN Zheng-kang2, GE Wei-peng1, WANG Kang2, WANG Fan1, SUN Jian-bao1   

  1. 1. State Key Laboratory of Earthquake Dynamics,Institute of Geology, China Earthquake Administration,Beijing 100029,China;
    2. School of the Earth and Space Sciences,Peking University,Beijing 100871,China
  • Received:2010-12-22 Revised:2011-03-29 Online:2011-09-29 Published:2011-12-16

摘要:

2010年4月14日青海玉树MW6.9地震发震断层为甘孜-玉树断裂NW段。断裂错动速率的准确估计能够为认识发震断裂的结构和地震的孕震过程提供帮助,甘孜-玉树断裂周边地区(89°~103°E,28°~39°N)1999-2007年的GPS观测使之成为可能。去除受到断裂锁定效应或其他断裂位错影响的数据后,将跨断裂剖面上的台站速率分解为平行断层和垂直断层2个分量,并进一步估算得到风火山断裂、甘孜-玉树断裂和鲜水河断裂NW段左旋走滑速率分别为(6.1±1.9)、(6.6±1.5)和(10.2±0.7)mm/a。结合该地区地质学研究结果,推测甘孜-玉树-鲜水河断裂自西向东逐段增强的走滑速率反映了不同区域地壳对印藏碰撞造成形变的转换、吸收方式之差异。甘孜-玉树断裂现今分段错动速率的定量估计为该断裂的深入研究和青藏高原变形发展过程的认识提供了宝贵数据。

关键词: 玉树地震, GPS, 断裂错动速率

Abstract:

The 14 April 2010 MW 6.9 Yushu earthquake ruptured the northwestern segment of the Ganzi-Yushu Fault in Qinghai,China.Accurate estimation of the secular slip rate across the fault would help understand tectonic structure of the fault and its seismogenic process.GPS data obtained from 1999 to 2007around the Ganzi-Yushu Fault spanning 89°~103°E,28°~39°N make such estimation possible.After removing GPS stations whose displacements were affected by fault locking effects and/or deformation of other faults,we decompose the remaining GPS station velocities into strike-parallel and strike-normal components and examine the data along profiles across corresponding fault segments.The slip rates of the Fenghuoshan,Ganzi-Yushu,and northwestern segment of the Xianshuihe Faults are estimated as 6.1±1.9,6.6±1.5,and 10.2±0.7mm/a,respectively.These results agree with geological estimates of the fault slip rates,which show progressive increase from northwest to southeast across segments of the Ganzi-Yushu-Xianshuihe Fault zone,implying variation in transferring and absorbing patterns of deformation in different regions in and around the Tibetan plateau.Estimation of present-day slip rates along segments of the Ganzi-Yushu Fault would provide valuable data for future research on seismo-tectonics of the fault and tectonic evolution of the Tibetan plateau.

Key words: Yushu earthquake, GPS, fault slip rate

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