Abstract: From the information oi active faults and focal mechanism the behaviour of fault zones is described plastically according to the increment concept.The stress field of the fault in relation to fault geometry and regional stress field is estimated numerically by using nonlinear finite element method.The Coulomb-Navier theory is used as criteria for failure of element in fault zones.For some elements'stresses are released with each time incremental step.Thus,a process of variation and adjustment of stress (ield of the fault can be simulated and the potential stress release area can also be determined on the basis of stress pattern of element.Combining the ratio of the radius of stress circle of future stress release area to that of the largest historical stress release area with the ratio of the volume of the future stress release area to that of the largest historical stress release area,we can estimate intensity of future stress release.