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NGA-subduction global ground motion models with regional adjustment factors

August 13, 2021

We develop semi-empirical ground motion models (GMMs) for peak ground acceleration, peak ground velocity, and 5%-damped pseudo-spectral accelerations for periods from 0.01 to 10 s, for the median orientation-independent horizontal component of subduction earthquake ground motion. The GMMs are applicable to interface and intraslab subduction earthquakes in Japan, Taiwan, Mexico, Central America, South America, Alaska, the Aleutian Islands, and Cascadia. The GMMs are developed using a combination of data inspection, data regression with respect to physics-informed functions, ground-motion simulations, and geometrical constraints for certain model components. The GMMs capture observed differences in source and path effects for interface and intraslab events, conditioned on moment magnitude, rupture distance, and hypocentral depth. Site effect and aleatory variability models are shared between event types. Regionalized GMM components include the model constant (that controls ground motion amplitude), anelastic attenuation, magnitude-scaling break point, linear site response, and sediment depth terms. We develop models for the aleatory between-event variability (τ)">(τ), within-event variability (ϕ)">(ϕ), single-station within-event variability (ϕSS)">(ϕSS), and site-to-site variability (ϕS2S)">(ϕS2S). Ergodic analyses should use the median GMM and aleatory variability computed using the between-event and within-event variability models. An analysis incorporating non-ergodic site response should use the median GMM at the reference shear-wave velocity condition, a site-specific site response model, and aleatory variability computed using the between-event and single-station within-event variability models. Epistemic uncertainty in the median model is represented by standard deviations on the regional model constants, which facilitates scaled-backbone representations of model uncertainty in hazard analyses.

Citation Information

Publication Year 2022
Title NGA-subduction global ground motion models with regional adjustment factors
DOI 10.1177/87552930211034889
Authors Grace Alexandra Parker, Jonathan P. Stewart, David Boore, Gail M. Atkinson, Behzad Hassani
Publication Type Article
Publication Subtype Journal Article
Series Title Earthquake Spectra
Index ID 70228362
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center

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