地震地质 ›› 2004, Vol. 26 ›› Issue (3): 426-435.

• 构造物理实验 • 上一篇    下一篇

基于声发射实验结果讨论大震前地震活动平静现象的机制

马胜利1, 蒋海昆2, 扈小燕1, 巴晶1   

  1. 1. 中国地震局地质研究所, 地震动力学国家重点实验室, 北京, 100029;
    2. 山东省地震局, 济南 250014
  • 收稿日期:2004-07-05 修回日期:2004-07-18 出版日期:2004-09-02 发布日期:2009-10-26
  • 作者简介:马胜利,男,1960年生,1997年在中国地震局地质研究所获得理学博士学位,研究员,主要从事实验构造物理学研究,电话:010-62009034,E-mail:masl@ies.ac.cn.
  • 基金资助:
    国家"十五"科技攻关项目(2001BA601B02和2004BA601B01)资助。中国地震局地质研究所论著2004B0033。

A DISCUSSION ON MECHANISM FOR SEISMIC QUIESCENCE BEFORE LARGE EARTHQUAKES BASED ON EXPERIMENTAL RESULTS OF ACOUSTIC EMISSION

MA Sheng-li1, JIANG Hai-kun2, HU Xiao-yan1, BA Jing1   

  1. 1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2. Earthquolce Administration of Shandong Provinace, Jinan 250014, China
  • Received:2004-07-05 Revised:2004-07-18 Online:2004-09-02 Published:2009-10-26

摘要: 基于岩石变形声发射实验结果讨论了大震前地震活动平静现象的机制。在双轴压缩、等位移速率加载条件下,挤压型雁列断层、含宏观凹凸体断层、Ⅲ型剪切断层等非连续断层在临近滑动失稳前,声发射活动均出现了明显的相对平静现象,表现为声发射事件的发生率和应变能释放水平显著降低。与此阶段相对应,断层带(特别是非连续部位上新形成的一小段断层)发生了蠕滑和匀阻化作用,并使得标本的差应力开始下降。根据实验结果提出,大地震前断层的“蠕滑-匀阻化”过程是造成地震活动平静现象的可能机制。

关键词: 声发射, 地震平静, 新生断层, 断层蠕滑

Abstract: This paper discusses the mechanism for seismic quiescence before large earthquakes based on experimental results of acoustic emission during rock deformation. Under the condition of biaxial compression and constant loading point velocity,samples simulating discontinuous faults,including compressional en-echelon faults,fault with macro-asperity,and model-Ⅲ shear fault,show relative quiescence of acoustic emission before slip instability,which is characterized by obvious decrease of occurrence rate and release of strain energy of acoustic emission events. The analysis indicates that the predominant deformation mode during this stage is creep sliding along fault zone,especially along the newborn fault segment in the discontinuous area,causing decrease of differential stress in the sample. The reason for occurrence of this stage is that a relatively uniform distribution of resistance along a fault zone is necessary for its slip instability,but uneven surface of newborn fault segment does not meet this condition,so the creep sliding is needed for resistance uniformization along the fault zone. Because there exist only very small asperities along the fault zone and the stress relaxation occurs in the whole sample during this stage,acoustic emission activity becomes weak. Based on the experimental results,it is suggested that the process of creep sliding and resistance-uniformization along fault zone is one possible mechanism for seismic quiescence before large earthquake.

Key words: acoustic emission, seismic quiescence, newborn fault, creep sliding

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