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地震 ›› 2009, Vol. 29 ›› Issue (1): 108-115.

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汶川8.0级地震前的地电阻率异常分析

张学民1, 李美2, 关华平1   

  1. 1.中国地震局地震预测研究所, 北京 100036;
    2.中国地震台网中心, 北京 100045
  • 收稿日期:2008-10-09 修回日期:2008-10-20 出版日期:2009-01-31 发布日期:2021-10-15
  • 作者简介:张学民(1969-), 女, 河北海兴人, 2005年获博士学位, 副研究员, 主要从事地震电磁分析及壳幔结构反演等研究。
  • 基金资助:
    中国地震局地震预测研究所基础科研业务经费资助

Anomaly Analysis of Earth Resistivity Observations before the Wenchuan Earthquake

ZHANG Xue-min1, LI Mei2, GUAN Hua-ping1   

  1. 1. Institute of Earthquake Science, CEA, Beijing 100036;
    2. China Earthquake Networks Center, CEA, Beijing 100045
  • Received:2008-10-09 Revised:2008-10-20 Online:2009-01-31 Published:2021-10-15

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摘要： 利用四川及邻近地区的地电阻率观测, 分析了汶川8.0级地震前的地电阻率异常现象。 结果表明, 这次汶川8.0级地震前, 距离震中最近的郫县观测台地电阻率在单测向下降幅度达到7.2%, 下降持续时间在2年左右, 震前5个月异常转折, 地震发生在地电阻率恢复上升阶段。 另外, 沿南北地震带多个台站在地震前2个月内出现阶变, 变化幅度最大超过10%。 地电阻率异常的方向性及台站空间分布特征反映了异常信息与构造走向及地震孕育机制之间的密切关系。

关键词: 地电阻率, 汶川8.0级地震, 下降异常, 南北地震带, 各向异性

Abstract: Based on the data of earth resistivity observations in Sichuan province and surrounding areas, anomalous phenomena of earth resistivity were analyzed. The results showed that, prior to the Wenchuan 8.0 Earthquake, the apparent resistivity amplitude at one observing direction decreased about 7.2% at Pixian station nearest to the epicenter, with duration time more than 2 years, and turned to rise 5 months before the quake, while the earthquake took place during the recovering stage. In addition, there were a few stations along the North-South Seismic Belt exhibiting step-wise variations 2 months prior to the quake, with maximal amplitude change exceeding 10%. The directional feature of earth resistivity anomalies and spatial distribution of anomalous stations reflected that the anomalies in earth resistivity observation was closely related to the strike of the tectonic belt and the earthquake mechanism.

Key words: Earth resistivity, Wenchuan earthquake, Decreasing anomaly, North-South Seismic Belt, Anisotropy

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