The description of earthquake ground motion based on local spectral density and its estimation methods

The history of investigation and description for earthquake ground motion is introduced, it is shown that the earthquake ground motion with non-stationary time-frequency characteristics should be depicted by time-dependent spectral density, i.e. local spectral density. By a detailed comparison of various local spectral density estimation methods, it is shown that wavelet transform is the best tool to estimate the local spectral density of earthquake ground motion regarding its precision and efficiency, and facilitates application of local spectral density to the ground motion modeling, structural analysis and the dynamic reliability evaluation.