Seismic ground motion simulations from a class of spatial variability models

An improved version of the spectral representation method (References 12–14) for the generation of simulations of random processes and random fields by means of the Fast Fourier Transform algorithm is developed. The new formulation produces simulations that are ergodic in the mean without any restricting assumptions at the origin of the spectra and leads to a faster convergence rate of the stochastic characteristics of the simulations to those of the random field. As an example of the methodology, simulations in space and time based on a spatial variability model for the seismic ground motions are generated.