The stress field variation caused by faulting and the prediction for seismic risk

Abstract

The stress field caused by faulting has an effect on the stability of the neighboring faults, and the study on the fault interaction has a close relation with the prediction of seismic risk. Stress field caused by the rectangle fault in the semi-infinite elastic medium is calculated on the basis of the elastic dislocation theory. The result shows that most of the successive large earthquakes, in the southwestern part of China and North China, occurred in the increasing area of shear stressS xy and the decreasing area of normal stressS yy. The increasing of earthquake occurrence probability has a function relation with the increasing of stress. Earthquake triggering is resulted from the increasing of shear stress and the decreasing of normal stress. An activation coefficientA t of the earthquake is defined to express the change of seismic activity. The concrete risk region can be obtained through space scanning ofA t value. Finally, the fault interaction in a large scope is discussed in this paper.