In order to estimate seismic surface rupture dislocation more accurately

the finite element method of pseudo-static elastoplasticity is used for numerical simulation to seismic surface rupture by strike-slip fault. In the numerical model

the two cases of silty clay and clay are discussed respectively. According to the relationship between magnitude M and bedrock dislocation Dbedrock which is regressed and fitted based on historical earthquake damage data and numerical calculation results

the relationship between magnitude M and surface dislocation Dsurface is set up. In the formula

the influence factor of soil thickness H is considered

and not just estimate surface rupture dislocation depending on magnitude by using statistical formula. The results show that: seismic surface rupture dislocation under strike-slip fault relates not only to magnitude

but to soil thickness and soil properties; Surface dislocation decreases gradually with the increasing of soil thickness under the same magnitude; Surface dislocation of silty clay is larger than that of clay under the same magnitude and soil thickness; The critical value of soil thickness without considering strike-slip fault is estimated based on the fitting formulas

and the result is helpful to improve the reliability of seismic risk evaluation of active fault.