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地震 ›› 2003, Vol. 23 ›› Issue (3): 79-88.

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荣昌5.2 级地震序列的震源参数及震区应力状态

程万正, 陈天长, 乔惠珍   

  1. 四川省地震局, 四川成都 610041
  • 收稿日期:2002-08-26 修回日期:2002-12-10 出版日期:2003-07-31 发布日期:2021-12-21
  • 作者简介:程万正(1950-), 男, 四川井研人, 研究员, 主要从事地震学和地震预报等研究。
  • 基金资助:
    国家重点基础研究发展规划项目(95130505)

Source parameters for the earthquake sequence of Rongchang M5.2

CHENG Wan-zheng, CHEN Tian-chang,QIAO Hui-zhen   

  • Received:2002-08-26 Revised:2002-12-10 Online:2003-07-31 Published:2021-12-21

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摘要： 分析了1997 年荣昌5.2 级地震的震源机制, 主压应力方位为NW 向, 震源力学作用机制呈走滑兼有较强的倾滑分量。根据成都遥测地震台网记录的波形资料, 研究了荣昌震区1994~1998 年36 次小震机制解, 统计的优势压应力方位也是NW 向。同时给出了小震震源参数随时间的变化过程, 其动态起伏过程稳定。在四川盆地及南缘地区, 发生走滑兼有较强的倾滑分量的地震破裂的比例相对较大。这往往与震区的地腹断裂有关, 也与分层滑脱的力学机制相一致。利用近场测震台测量的快S 波偏振显示震区近地表浅层介质的各向异性特征。

关键词: 地震序列, 震源参数, 应力状态, 荣昌

Abstract: In this paper the focal mechanism for M5.2 earthquake occurred in Rongchang, Chongqing Municipality on August 13, 1997, is analyzed.The direction of the principal compressional stress is in NW.And faulting plane is characterized by obvious normal dip slip component.Focal mechanisms for 36 small events located in Rongchang region are determined by using waveform data in 1994 ~ 1998 from Chengdu telemetering Seismic Network.The dominant direction of compressional stress is also in NW.Changes of source parameters for the small earthquakes with time demonstrate stable dynamic process with small fluctuations.There is relatively larger percentage of earthquake faulting with obvious dip slip component in Sichuan Basin and on its southern fringe.That is usually related to buried faults in epicentral areas, and also consistent with layered detachment mechanism as well.The polarization of fast S waves measured on recordings from near stations shows anisotropy in shallow medium near the free surface.

Key words: Earthquake sequence, Source parameter, Stress state, Rongchang

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