A Suite of Alternative Ground-Motion Models (GMMs) for Israel

Abstract

Models for estimating earthquake ground motions are a key component in seismic hazard analysis. In data-rich regions, these models are mostly empirical, relying on the ever-increasing ground-motion databases. However, in areas in which strong-motion data are scarce, other approaches for ground-motion estimates are sought, including, but not limited to, the use of simulations to replace empirical data. In Israel, despite a clear seismic hazard posed by the active plate boundary on its eastern border, the instrumental record is sparse and poor, leading to the use of global models for hazard estimation in the building code and all other engineering applications. In this study, we develop a suite of alternative ground-motion models for Israel, based on an empirical database from Israel as well as on four data-calibrated synthetic databases. Two host models are used to constrain model behavior, such that the epistemic uncertainty is captured and characterized. Despite the lack of empirical data at large magnitudes and short distances, constraints based on the host models or on the physical grounds provided by simulations ensure these models are appropriate for engineering applications. The models presented herein are cast in terms of the Fourier amplitude spectra, which is a linear, physical representation of ground motions. The models are suitable for shallow crustal earthquakes; they include an estimate of the median and the aleatory variability, and are applicable in the magnitude range of 3–8 and distance range of 1–300 km.

Engineering-oriented ground-motion model for Israel

“…The dataset used for regression is a synthetic dataset, which has a uniform distribution in the magnitude distance (M-R) domain (see Figure 1a). The synthetic dataset was created as follows: first, a weighted mean model in FAS was calculated using the nine models in Maiti et al (2021). The weights were distributed such that the empirical model received 50%, the low stress-drop simulation models received 25% and the high stress-drop simulation models received the remaining 25%.…”

“…In this study, we continue the work of Maiti et al (2021), by developing a practice-oriented responsespectral GMM and testing its effect on the computed seismic hazard. The model is based on a weighted average of the nine alternative MYK21 models, with additional parameters that are significant for forward-analysis engineering applications.…”

“…This is mostly due to lack of empirical data within the magnitude range applicable to hazard. The existing GMMs are either based on too little data (Meirova et al 2008), do not cover the full spectrum (Lior and Ziv 2018), or do not include all relevant parameters for engineering applications (Maiti et al 2021). That is why the Israeli national seismic hazard map, used in the building code, uses the Campbell and Bozorgnia (2008) GMM, which is therefore often used in practice, without any adjustment or validation.…”

“…In a recent study, Maiti et al (2021) developed a suite of alternative GMMs for Israel in terms of the Fourier amplitude spectra (FAS). The models are based on different datasets and different functional forms, to ensure that both modeling and parametric epistemic uncertainty are captured.…”

“…

This study presents a response-spectral Ground Motion Model (GMM) for Israel, called KYB22 herein and derived with practical applications in mind. This model is based on the former work by Maiti et al (2021), which derived a suite of nine Fourier amplitude spectra GMMs, based on both empirical data and calibrated point-source simulations. In this study, a weighted average of the Maiti et al ( 2021) FAS models is computed and a synthetic database is created.

…”