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地震 ›› 2019, Vol. 39 ›› Issue (1): 1-10.

• •    下一篇

南北地震带地震震源机制解和现今应力特征

崔子健1,2, 陈章立3, 王勤彩2, 李君4   

  1. 1.中国地震局地球物理研究所, 北京 100081;
    2.中国地震局地震预测研究所地震预测重点实验室, 北京 100036;
    3.中国地震局, 北京 100036;
    4.中国地震局第二监测中心, 陕西 西安 710054
  • 收稿日期:2018-06-05 出版日期:2019-01-31 发布日期:2019-01-31
  • 作者简介:崔子健(1983-), 男, 山东济南人, 助理研究员, 主要从事数字地震学及地震预测方法等研究。
  • 基金资助:
    中国地震局地震预测研究所基本科研业务费专项(2017IES0201, 2018IEF010203)资助

Characteristics of Focal Mechanism and Stress in the North-South Seismic Belt of China

CUI Zi-jian1,2, CHEN Zhang-li3, WANG Qin-cai2, LI Jun4   

  1. 1.Institute of Geophysics, CEA, Beijing 100081, China;
    2.Key Laboratory of Earthquake Prediction, Institute of Earthquake Forecasting, CEA, Beijing 100036, China;
    3.China Earthquake Administration, Beijing 100036, China;
    4.The Second Monitoring and Application Center, CEA, Xi’an 710054, China
  • Received:2018-06-05 Online:2019-01-31 Published:2019-01-31

摘要: 基于CAP方法, 使用地震波形资料, 计算得到了2009年1月~2017年8月期间南北地震带及周边区域466个3.5级以上地震震源机制解。 在补充收集1976年1月~2017年8月GCMT公布的259个4.5级以上地震震源机制解的基础上, 分析了南北地震带地震震源机制解和应力特征。 震源机制空间分布显示, 不同断裂带、 块体间表现出不同的震源机制空间分布特征, 该特征与南北地震带不同段落活动构造性质基本吻合。 作为青藏高原东边界的南北地震带, 由于动力环境复杂, 其内部P轴方向具有明显的差异性。 这种差异主要表现为: 南北地震带北段P轴呈NE向分布; 龙门山断裂带及周边除NE段P轴取向为NW—NNW向外, 其他地段P轴近EW向; 川滇菱形块体内部P轴呈NNW向, 而其西边界以西呈NNE向, 东边界以东呈NW向, 应力方向转换带的与川滇菱形块体边界基本一致。 整体而言, 南北地震带及近邻P轴方向由北到南发生了顺时针转动。

关键词: 南北地震带, 震源机制, CAP方法, 应力场

Abstract: Using the CAP method, the focal mechanisms of 466 M≥3.5 events that occurred in the North-South Seismic Belt from January 2009 to October 2017 have been obtained. Combining the results of 259 focal mechanisms (M≥4.5) from January 1976 to August 2017 from the GCMT, we investigated the characteristics of focal mechanisms and stress in the North-South Seismic Belt of China. The spatial distributions of focal mechanisms differ among different faults and blocks. It is consistent with active tectonics along the North-South Seismic Belt, mostly in eastern margin of the Tibetan Plateau. Under the complex dynamic environment in eastern margin of the Tibetan Plateau, the P axes directions vary much inside the North-South Seismic Belt. The P axes in the northern section of the North-South Seismic Belt are NE direction. In and surround the Longmenshan fault zone the P axes are nearly EW direction except the NE segment which are NW direction. Inside the Sichuan-Yunnan rhombic block the P axes are NNW direction, while in the west of the west boundary are NNE direction, in the east of the east boundary are NW direction. The stress direction transition bands correspond well with the Sichuan-Yunnan rhombic block boundary. Overall, the P axes in the North-South Seismic Belt and its neighbor area have a clockwise rotational pattern from north to south.

Key words: North-South Seismic Belt of China, Focal mechanism, CAP method, Stress

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