Stochastic model for simulation of near‐fault ground motions

Abstract

Summary A parameterized stochastic model of near‐fault ground motion in two orthogonal horizontal directions is developed. The major characteristics of recorded near‐fault ground motions are represented. These include near‐fault effects of directivity and fling step; temporal and spectral non‐stationarity; intensity, duration, and frequency content characteristics; directionality of components; and the natural variability of ground motions. Not all near‐fault ground motions contain a forward directivity pulse, even when the conditions for such a pulse are favorable. The proposed model accounts for both pulse‐like and non‐pulse‐like cases. The model is fitted to recorded near‐fault ground motions by matching important characteristics, thus generating an ‘observed’ set of model parameters for different earthquake source and site characteristics. A method to generate and post‐process synthetic motions for specified model parameters is also presented. Synthetic ground motion time series are generated using fitted parameter values. They are compared with corresponding recorded motions to validate the proposed model and simulation procedure. The use of synthetic motions in addition to or in place of recorded motions is desirable in performance‐based earthquake engineering applications, particularly when recorded motions are scarce or when they are unavailable for a specified design scenario. Copyright © 2016 John Wiley & Sons, Ltd.

Simulation of orthogonal horizontal components of near‐fault ground motion for specified earthquake source and site characteristics

“…[1][2][3] See our recent paper 4 for a brief review of the characteristics of near-fault ground motions. Moreover, recently, there has been increased effort in characterizing near-fault ground motions.…”

“…They include source-based deterministic models, 1,17,18 source-based stochastic models, [19][20][21] site-based stochastic models, 4,[22][23][24][25] and hybrid models. They include source-based deterministic models, 1,17,18 source-based stochastic models, [19][20][21] site-based stochastic models, 4,[22][23][24][25] and hybrid models.…”

“…Such relations can be developed for parametrized models by fitting them to a catalog of recorded motions and performing statistical analysis. Predictive relations that account for the natural variability of the parameters of the pulse model in Mavroeidis and Papageorgiou 19 have been recently presented in Halldórsson et al and Cork et al 20,33 In our previous work, 4 we developed a site-based parameterized stochastic model of near-fault ground motion in 2 orthogonal horizontal directions. [19][20][21][22][23] Furthermore, some site-based models characterize only the directivity pulse and were fitted to recorded near-fault ground motions.…”

“…However, some previous attempts in this direction have failed to fully account for the variability of all the model parameters [21][22][23] or for the correlations between them. 4 Moreover, a procedure to generate and postprocess synthetic motions for specified model parameters was described in that reference and used to generate synthetic ground motions that possess characteristics similar to recorded near-fault ground motions. 15,[28][29][30] Predictive relations are developed for the parameters of some of these pulse models.…”

“…4 The model is then fitted to subsets of PEER's NGA-West2 database to obtain empirical "observations" of the model parameters. The paper begins with a brief review of the characteristics of near-fault ground motions, followed by a summary of the stochastic models of pulse-like and non-pulse-like near-fault ground motions in Dabaghi and Der Kiureghian.…”