Probabilistic generation of hazard-consistent suites of fully non-stationary seismic records

Abstract

A novel, practical, and computationally efficient probabilistic methodology for the stochastic generation of suites of fully non-stationary artificial accelerograms is presented. The proposed methodology ensures that the produced ground motion suites match a given target spectral mean and target variability for the whole period range of interest. This is achieved by first producing an ensemble of random target spectra with the given mean and variability and then using them to generate artificial, target spectrum-compatible, acceleration time-histories with spectral representation techniques. Spectral correlation can also be assumed for the generated ground motion spectra. Based on the same backbone, two different formulations are proposed for generating spectrum-compatible acceleration time-histories of the non-stationary kind. The distinction between these two variants lies in the techniques employed for modeling the temporal and spectral modulation, focusing on the site-compatibility of the produced records. The first approach uses past-recorded seismic accelerograms as seed records, and the second proposes and uses a new, probabilistic time-frequency modulating function. The outcome of the proposed methodology is suites containing site-compatible ground motion time-histories whose spectral mean and variability match those obtained from any of the usually employed target spectra used in the earthquake engineering practice. An online tool implementing the proposed methodology is also freely provided.