Broadband Simulation of Earthquake Ground Motion by a Spectrum-Matching,Multiple-Pulse Technique

A kinematic, stochastic fault model and simulation procedure is proposed for realistic, application-oriented simulation of earthquake ground motion. An extended fault plane is discretized as a grid of point subsources. Subsource signal, in its low-frequency part, is produced by a dislocation strip sweeping the fault area. In its high-frequency part, it is defined by random local slip history, represented by a segment of pulsed noise. Subsource signals are convolved with broad-band Green functions for a layered half-space, and stacked, resulting in the ground motion at a site. Through a special choice of subsource signals, the Fourier spectrum of ground motion obeys an observation-based scaling law. Effects of the rupture velocity behavior, rise time, wavenumber spectrum for the final slip, the degree of spikiness of time functions etc can be easily analyzed. For illustration, several near-source 1994 Northridge earthquake records are simulated, and related uncertainties are estimated.