山东及附近区域部分中小地震震源机制特征分析

收集了2001~2006年4月山东及周边省记录的20次(其中有8次地震为2003年青岛震群地震)中等地震波形资料。并对上述地震进行了重新定位。根据各台站记录的P波、SV波、SH波初动和它们之间的振幅比,利用Snoke联合计算地震震源机制解的程序,计算了20次地震震源机制解。就所研究的震例来看,断层破裂错动方式以近于走滑错动为主,在NE向断裂上为右旋错动,在NW向断裂上为左旋错动。大部分地震发生在现有断裂上,并且破裂方向与其断裂构造相吻合,这表明,现有断裂构造对中小地震的破裂方式有控制作用。

Characteristics of the focal mechanism for parts of moderate and small earthquakes in Shandong and its neighboring region

The waveform data of 20 medium earthquakes recorded by Shandong and its neighboring Province from 2001 to Apr.2006 is collected,and the earthquake is relocated.Based on the first motion of P wave,SV wave,SH wave and their amplitude ratio,the focal mechanisms of the 20 earthquakes are calculated with Snoke program.The results show that the fracture of faults is mainly strike slip,which is dextral for the faults in NE direction,and sinistral for the faults in NW direction.Most earthquakes occurred on the current faults,and the fracture direction is consistent with the structure of the fault.It is concluded that the facture of medium and small earthquake is controlled by current fault structure.