Fully Nonstationary Analytical Earthquake Ground-Motion Model

TLDR

The study formulates and validates a versatile nonstationary stochastic ground‑motion model that captures time‑varying intensity and frequency content of real earthquakes. The model employs an adaptive Thomson spectrum estimation to compute the evolutionary PSD, fits its parameters via least‑square matching to the target PSD, and is validated on two real records by comparing second‑order statistics and probabilistic spectra with deterministic counterparts.

Abstract

A versatile, nonstationary stochastic ground-motion model accounting for the time variation of both intensity and frequency content typical of real earthquake ground motions is formulated and validated. An extension of the Thomson's spectrum estimation method is used to adaptively estimate the evolutionary power spectral density (PSD) function of the target ground acceleration record. The parameters of this continuous-time, analytical, stochastic earthquake model are determined by least-square fitting the analytical evolutionary PSD function of the model to the target evolutionary PSD function estimated. As application examples, the proposed model is applied to two actual earthquake records. In each case, model validation is obtained by comparing the second-order statistics of several traditional ground-motion parameters and the probabilistic linear-elastic response spectra simulated using the earthquake model with their deterministic counterparts characterizing the target record.