云南禄劝地震对余震有触发作用吗--静态应力触发地震的讨论

采用文献[1]计算地震产生的静态应变场的解析表达式,对云南禄劝地震的15次余震,计算了主震在余震节面上产生的正应力和静态库仑破裂应力变化。分析了正应力变化和静态库仑破裂应力变化是否对余震有触发作用。结果表明,主震产生的正应力变化和库仑破裂应力变化并没有明显的证据“有利于”余震的发生。另外,还比较了运用与主震相同的余震机制和反演得到的余震机制在库仑破裂模型中计算结果的差异。使用反演的余震机制得出的结果稍优于假定余震与主震有相同震源机制得到的结果。

Have Luquan,Yunnan, Earthquake the Effect to Trigger Off Aftershocks--Discussion An Example That Earthquake Is Triggered by Static Stress

The normal stress and static Coulomb's failure stress produced on the nodal plane of aftershocks of the main shock,for 15 aftershocks of the Luquan earthquake,are calculated,by using Okada's(1992) analytical expression of static strain field,caused by earthquake.Whether the normal stress and static Coulomb failure stress have the effect on triggering aftershocks is analyzed.The result shows that there is no obvious evidence that the variations of the normal stress and Coulomb's failure stress caused by main shock are good for occurrence of aftershocks.In addition,the difference of calculated results in Coulomb rupture model between using the which is as same as the main shock's and using focal mechanism of aftershocks from inversion is compared.The result using the focal mechanism of aftershocks from inversion is slightly better than that assuming that the aftershocks have the same focal mechanism as the main shock's.