青藏高原东部及邻区地震断层面上的潮汐应力触发效应  

The effect of tidal triggering on seismic fault in eastern Tibetan plateau and its neighboring areas

作　　者：孙长青[1] 阎春恒 吴小平[3] 许亚吉[4] 

机构地区：[1]中国地震局地壳应力研究所(地壳动力学重点实验室),北京100085 [2]广西壮族自治区地震局,南宁530022 [3]云南大学地球物理系,昆明650091 [4]云南省地震局,昆明650041

出　　处：《地球物理学报》2014年第7期2054-2064,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41074044);桂科攻项目(12426001);基本科研业务专项(ZDJ2012-19)共同资助

摘　　要：根据已发布震源机制解目录(哈佛大学CMT),将青藏高原东部及邻区划分为5个构造应力场分区,并对各分区的地震逐个计算其发震断层面上的固体潮汐正应力、剪应力、库仑破裂应力及相位角,分析潮汐应力分量对不同类型发震断层的作用效果及其随深度变化特征.基于库仑破裂应力判断准则,研究潮汐应力对各种类型地震的触发作用;基于Schuster检验方法,统计分析潮汐应力对各个震级档、不同构造类型地震的影响.综合运用上述两种分析方法,探讨潮汐应力对不同震级地震以及处于不同构造块体、发震断层、震源深度地震的触发机制.结果表明,潮汐应力对印度块体和拉萨块体的正断和逆断型地震,滇缅泰块体、印支块体和松潘一甘孜块体的走滑和斜滑型地震,川滇菱形块体的斜滑型地震均存在不同程度的触发效应,且触发效应的强弱依赖于震源深度、震级大小、发震断层类型及其所处区域构造应力场.In this study, according to the Harvard CMT catalog, the tidal normal stress, shear stress, Coulomb failure stress and phase angle on the surface of seismic fault of 363 earthquakes were calculated in eastern Tibetan plateau and its neighboring areas, which were divided into 5 tectonic districts. Tidal stress components on different kinds of seismogenic fault and its variation characteristics with depth were analyzed. Using Coulomb failure stress criterion, the effect of tidal triggering on various earthquakes was obtained. The Schusterrs test was used to analyze the effect of tidal stress on earthquakes of different magnitude and tectonic types. Using the two methods above mentioned comprehensively, we explored the effect of tidal triggering on earthquakes of different magnitude, tectonic district, seismogenie fault and depth. Our results show that tidal triggering was obvious on normal and thrust fault earthquakes in Indian block and Lhasa block, strike and oblique slip fault earthquakes in Yunnan-Myanmar-Thailand block, Indochina block and Songpan-Garze block, oblique slip fault earthquakes in Sichuan-Yunnan Diamond block. Moreover, the effect of tidal triggering depended on the depth and magnitude of earthquake, the fault of seismogenic fault and regional tectonic stress field.

关 键 词：构造应力分区 潮汐库仑破裂应力 Schuster检验 潮汐触发 青藏高原东部及邻区 

分 类 号：P315[天文地球—地震学]