Random field model of sequential ground motions

This paper proposes a random field model of sequential ground motions, which considers the spatial correlation between the mainshock and aftershock from a stochastic view. First, the correlation between the mainshock and aftershock under the physical source-path-local site mechanism is explained. Based on the mechanism, the point-source model, and uniform-isotropic-medium model, a random single-point model for sequential ground motion with eight basic parameters is presented. Second, the random field model is developed from the random single-point model. More than 1000 pairs of sequential ground motions are used to identify and analyze statistically the basic parameters in the model. Moreover, the probability distribution of each parameter is presented based on copula functions. The results show that the spatial correlations of sequential ground motions can be effectively simulated based on the proposed random field model. Furthermore, it is possible to realistically reproduce the attenuation and time lag of ground motions at a local site.