Simulation of Correlated Horizontal Seismic Ground Motion Time Histories for a Given Scenario

Reliable seismic vulnerability analysis is generally based on time-domain simulations of structural responses. The seismic load is then modelled by a stochastic process, representing seismic ground motion. For this purpose, the analyst can use recorded accelerograms or work with synthetically generated ones. When performing advanced probabilistic analyses, synthetic accelerograms are often used since available strong motion data is not sufficient. It is then necessary to have at our disposal methods that allow for generating synthetic accelerograms that realistically characterize earthquake ground motion. In particular, they have to accurately reproduce the natural variability of ground motion parameters related to the chosen site specific scenario. We present a method for generating two-dimensional synthetic ground motion reproducing variability in ground motion parameters and response spectra as observed for natural accelerograms. The proposed procedure uses Karhunen-Loève decomposition and a general (non-Gaussian) stochastic model in order to simulate ground motion time histories accounting for the space-time correlation structure of the two horizontal components This contribution presents an extension of an earlier work by the authors on seismic ground motion models.