2008年5月12日四川汶川8.0级地震前后震源区应力水平估计

Estimation of the Stress Levels in the Focal Region Before and After the May 12, 2008 Wenchuan, Sichuan Earthquake With M_S8.0

根据地震力学和数字地震学理论,利用视应力和应力降,估算了2008年5月12日四川汶川MS8.0级地震前后震源区的应力水平,结果表明,震前震源区应力值约为1.5~2.0MPa,地震破裂过程中,由于断层发生错动过头,使地震发生后震源区应力低于动摩擦力,降至-1.2^-0.1MPa。

The stress levels in the focal region of the May 12,2008 Wenchuan, Sichuan earthquake of Ms8.0 before and after its occurrence are estimated. The results show that the stress level on the fault plane in the focal region just prior to the initiation of the event is approximately 1.5 2.0 MPa, and about - 1.2 - - 0.1 MPa remaining on the fault plane after this event occurred. As the fault dislocation overshooted during the mainshock, so the final stress is lower than the dynamic frictional stress on the fault plane.