SEISMOLOGY AND GEOLOGY ›› 2015, Vol. 37 ›› Issue (4): 939-952.DOI: 10.3969/j.issn.0253-4967.2015.04.001

• Special topic on earthquake prediction method • Previous Articles     Next Articles

study on crustal velocity structure beneath kouquan fault and adjacent area

WANG Xia1,2, SONG Mei-qin1,2, WANG Liang3, LI Hong-wei1, WU Hao-yu1, LUO Yong1   

  1. 1. Earthquake Administration of Shanxi Province, Taiyuan 030021, China;
    2. State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China;
    3. Earthquake Administration of Liaoning Province, Shenyang 110034, China
  • Received:2015-10-26 Online:2015-12-20 Published:2016-01-28

口泉断裂及其邻近地区的地壳速度结构

王霞1,2, 宋美琴1,2, 王亮3, 李宏伟1, 吴昊昱1, 罗勇1   

  1. 1. 山西省地震局, 太原 030021;
    2. 中国科学院测量与地球物理研究所, 大地测量与地球动力学国家重点实验室, 武汉 430077;
    3. 辽宁省地震局, 沈阳 110034
  • 通讯作者: 宋美琴
  • 作者简介:王霞, 女, 1987年生, 2012年毕业于中国地质大学(北京)矿产普查与勘探专业, 获硕士学位, 工程师, 主要从事地震综合预测等研究, 电话: 0350-5610572, E-mail: 365372858@qq.com。
  • 基金资助:

    大地测量与地球动力学国家重点实验室开放基金(SKLGED201444E)、中国地震局星火计划(Xh15007)和2014年度震情跟踪专项工作任务(2014020111)共同资助。

Abstract:

Through simultaneous inversion of earthquake hypocenters and velocity structure, we obtained the precise locations of earthquakes occurring from 1981 to 2013 in northern Shanxi and the 3D velocity structure, and analyzed emphatically the Kouquan Fault. The result of earthquake relocation shows that earthquakes are concentrated in the central-north segment of Kouquan Fault and the distribution is sparse towards both south and north end of the fault, which indicates that the strong activity is in the central-north segment of Kouquan Fault and the seismicity becomes weaker towards both ends. The result of velocity structure shows that the earthquake concentrated segment of Kouquan Fault is on the side of relative low-velocity area in the high-velocity body, and the south segment of Kouquan Fault is the continuous low velocity. We can recognize the velocity gradient zone from the obvious depression near the Kouquan Fault, which, as we preliminarily speculate, may be the evidence of the presence of Kouquan Fault(or basement detachment)at the deep part. The parallel velocity profile (velocity ratio profile) to Kouquan Fault shows that the earthquake cluster in the central-north segment of Kouquan Fault is located in the abrupt change zone from high to low velocity(from high to low velocity ratio).

Key words: velocity structure, simultaneous inversion, Kouquan Fault

摘要:

利用震源位置和速度结构联合反演方法, 对1981—2013年山西北部地区的地震进行了重定位, 反演得到了三维速度结构, 并重点对口泉断裂进行了分析。重定位结果显示, 口泉断裂中北段地震集中, 其南北两端地震分布较少, 表明该断裂中北段活动强而南北两端弱; 速度结构显示口泉断裂地震集中段位于高速体内的相对低速区域,其南段显示持续的低速异常。从垂直口泉断裂的速度结构剖面上可以识别出口泉断裂附近的速度呈现明显下凹的梯度带, 初步推测这可能是口泉断裂(或基底拆离带)存在的深部证据; 平行口泉断裂的速度(波速比)剖面显示其中北段地震丛位于高、低速(高低波速比)陡变带之间。

关键词: 速度结构, 联合反演, 口泉断裂

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