【摘要】 利用昆明数字化地震台网记录的数字化地震波形资料,测算了云南及邻区2002年到2004年8月2 513个中小地震的剪应力值0τ和矩震级值MW,分析了它们之间的相关关系。研究表明,地震剪应力值与地震大小存在线性依赖关系,地震越大,环境剪应力场越强,强震的发生需要较强的剪应力场环境。小地震在较弱的环境剪应力场状态下也可以发生,随机性较强。在环境剪应力场较强的地方,会发生强震,也会发生数量众多的中小地震。而在环境剪应力场较弱的地方,往往只会发生中小震。统计分析表明,通常,中小地震的0τ<10 MPa,将0τ≥10 MPa的地震视为高剪应力值地震,高剪应力值地震集中分布的区域,或应力等值线大于10 MPa的分布区即为高应力值区,高剪应力值分布区是环境剪应力场的异常分布区,它的形成和分布往往与强震的发生有关。据此,对云南省环境剪应力场动态变化及其与地震活动的关系作了分析研究。更多还原

【Abstract】 In order to study the relation between the environment shear stress field change and seismic activity in the Yunnan area,we calculated the shear stress value τ₀ and moment magnitude value M_W of（2513） moderate-small earthquakes on the basis of the waveform data recorded by Kunming Regional Digital Seismic Network,and found there exists linear correlation between environment shear stress value and the size of an earthquake,namely,the bigger the shock is,the stronger the environment shear stress is.In the places with strong environment shear stress,it is possible to occur a strong earthquake or lots of moderate or small earthquakes;however,in the places with weak environment shear stress,it is possible just to occur moderate or small earthquakes.The statistical analysis shows that,usually,τ₀ <10 MPa for moderate-small earthquakes,while the occurrence of the strong earthquake is often relative to the forming and distribution of high shear stress value areas,i.e.,the areas concentrated by high shear stress value earthquakes（τ₀ ≥10 MPa） or with the stress isolines more than 10 MPa.更多还原