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地震 ›› 2005, Vol. 25 ›› Issue (3): 109-114.

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2004年阳江MS4.9地震震源参数分析

康英, 杨选, 吕金水, 叶繁英   

  1. 广东省地震局, 广东 广州 510070
  • 收稿日期:2004-11-03 修回日期:2004-12-17 出版日期:2005-07-31 发布日期:2021-11-10
  • 作者简介:康英(1967-), 女, 甘肃永靖人, 高级工程师, 主要从事地震监测和数字地震等研究。
  • 基金资助:
    国家重大基础前提研究专项(2002CCD01700)资助

Analysis on the source parameters of Yangjiang earthquake with MS4.9 in 2004

KANG Ying, YANG Xuan, LU Jin-shui, YE Fan-ying   

  1. Earthquake Administration of Guangdong Province, Guangzhou 51000, China
  • Received:2004-11-03 Revised:2004-12-17 Online:2005-07-31 Published:2021-11-10

摘要: 利用广东数字地震台网的资料计算了2004年9月17日广东阳江MS4.9地震的震源机制为: 节面走向57°, 倾角47°, 滑动角69°, 主压应力方向342°, 倾角0°, 主张应力方向252°, 倾角75°, 属逆断层性质; 地震矩为1.69×1015 N·m, 应力降为1.7 MPa, 震源半径为876 m。 根据阳江地区震前22个ML>2.5的中小地震震源参数, 得到一些经验关系。 S波拐角频率随时间的变化显示出MS4.9地震前有下降趋势; 阳江序列P轴方位角的变化显示出震前4个月应力开始趋于一致。

关键词: 震源参数, 震源机制, 阳江MS4.9地震, 拐角频率

Abstract: According to the Guangdong Digital Seismic Network records, the focal mechanism is obtained from the earthquake (MS4.9) in Yangjiang on September 17, 2004. The strike is 57°, the dip angle is 47° and the rake is 69° of the nodal plane, the azimuth and the dip angle of principal compressional stress axes P is 342° and 0°, respectively; the azimuth and the dip angle of principal extensional stress axes T is 252° and 75°, respectively, the type is reverse faulting. The seismic moment is 1.69×1015 N·m, the stress drop is 1.7 MPa, the source radius is 876m of this earthquakes. Some relations are obtained by analyzing source parameters of the 22 moderate-small earthquakes in Yangjiang area. The descent trend of corner frequency of S wave is showed by the changes of the time before the earthquake (MS4.9), the azimuth of axes P of Yangjiang sequence show that the stress has begun to be identical in four months before this event.

Key words: Source parameter, Focal mechanism, Yangjiang earthquake (MS4.9), Corner frequency

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