Research on the non-stationary model of three-dimensional ground motion intensity based on KiK-net earthquake records

Non-stationary characteristics of ground motion intensity have remarkable effect on the nonlinear response of structures, and accurate description of non-stationary characteristics of ground motion intensity is of significance to generating artificial earthquakes. In this work, a model for non-stationary characteristics of three-dimensional ground motion intensity was proposed, and the values were given for the deterministic parameters and the stochastic parameters, respectively. Firstly, a series of actual non-stationary characteristics were extracted from a large number of KiK-net earthquake records. Then, a non-stationary model of ground motion intensity was chosen and its parameters were identified by the genetic algorithm. At last, the parameter values were determined for the three-dimensional model under different earthquake magnitude, epicentral distances and site conditions. The results show that the model proposed in this study can reflect the law of non-stationary characteristics of ground motion intensity, and it can be used in structural anti-seismic analysis and artificial earthquake simulation.