中国地震震源机制测定结果的比较

China seismic mechanisms comparison for different determination

在搜集了 1 988年以来 ,地震学家用不同方法和不同资料测定的中国地震震源机制结果 ,包括用地震波形反演得到的地震矩张量、P波初动解和用地形变观测反演的震源参数的基础上 ,计算了同一地震的不同反演结果的滑动矢量之间的夹角、不同反演结果 P,T轴之间的夹角和不同的反演结果给出的地震矩之间的差别 ;并与哈佛 CMT的结果进行比较。结果表明 ,同一地震不同测定结果的滑动矢量之间的夹角分布较分散 ,但优势分布在 2 0°左右 ;不同测定结果的地震矩一般不超过 1倍 ,对应的震级差约为 0 .2 ;中国地震矩张量的测定结果与哈佛矩心矩张量测定结果滑动矢量之间的夹角集中在 0°～ 1 0°。以丽江地震为例 ,讨论了地震震源参数的不同结果对地震“应力触发”中库仑破裂应力计算结果的影响。

Collected different determination seismic mechanism results using different methods and different data since 1988.It includes seismic moment tensor using seismic wave data inversion,fault plane solutions using P first arrivals and seismic parameters using deformation data.Calculated angles between slip vectors and between P and T axis of the different inversion results in the same earthquake.It gives the differences of seismic moment in the same earthquake.All of above are compared with Harvard CMT determinations.It shows that angles of slip vectors in the same earthquake is scatter,with predominance frequency at about 20°.Seismic moment difference cannot be greater than 1 fold,corresponding to magnitude difference about 0 2.Slip vectors determining from seismic moment tensor solution of China seismologists and Harvard CMT solution have angle of 1～10°.At last,we discuss difference seismic parameters has different effects at Coulomb failure stress calculations in'stress triggering'.