Generation of Uniform-Hazard Earthquake Ground Motions

Abstract

This paper presents statistical models for the generation of biaxial earthquake ground-motion time histories with spectra that match those from samples of ground-motion records. The model parameters define near-field characteristics such as pulse velocity and pulse period, far-fault characteristics such as velocity amplitude and power spectral density, and envelope characteristics. The samples of ground motions used in this study were previously selected and scaled to be representative of particular hazard levels in particular geographical regions. A companion paper presents the fitting of the model to samples of ground-motion waveforms. In this paper, the new concept of a parameter-response correlation spectrum establishes the period-dependence of the correlation between the response spectrum and ground-motion parameters. Parameters that correlate to variability of the response spectra are retained as random variables and then fit to mean and mean-plus-standard deviation of biaxial response spectra of the samples of historical records. Parameter statistics also include correlations between velocity amplitudes and pulse periods.