Abstract

Empirical ground‐motion prediction equations (GMPEs) require adjustment to make them appropriate for site‐specific scenarios. However, the process of making such adjustments remains a challenge. This article presents a holistic framework for the development of a response spectral GMPE that is easily adjustable to different seismological conditions and does not suffer from the practical problems associated with adjustments in the response spectral domain. The approach for developing a response spectral GMPE is unique, because it combines the predictions of empirical models for the two model components that characterize the spectral and temporal behavior of the ground motion. Essentially, as described in its initial form by Bora et al. (2014), the approach consists of an empirical model for the Fourier amplitude spectrum (FAS) and a model for the ground‐motion duration. These two components are combined within the random vibration theory framework to obtain predictions of response spectral ordinates. In addition, FAS corresponding to individual acceleration records are extrapolated beyond the useable frequencies using the stochastic FAS model, obtained by inversion as described in Edwards and Fäh (2013a). To that end, a (oscillator) frequency‐dependent duration model, consistent with the empirical FAS model, is also derived. This makes it possible to generate a response spectral model that is easily adjustable to different sets of seismological parameters, such as the stress parameter Δσ, quality factor Q, and kappa κ0. The dataset used in Bora et al. (2014), a subset of the RESORCE‐2012 database, is considered for the present analysis. Based upon the range of the predictor variables in the selected dataset, the present response spectral GMPE should be considered applicable over the magnitude range of 4≤Mw≤7.6 at distances ≤200  km.

Online Material: GMPE scaling with respect to distance, moment magnitude, VS30, stress parameter and kappa, ratios for various parameters, and median response.

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