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Probabilistic Seismic Hazard Analysis in California Using Non-Ergodic Ground-Motion Prediction Equations

Nicolas M. Kuehn, Norman A. Abrahamson, & Melanie Walling

Published August 15, 2018, SCEC Contribution #8630, 2018 SCEC Annual Meeting Poster #025

With an increasing number of strong-motion records over the last decade, it has become clear that there are significant differences in ground-motion scaling even within relatively small regions such as California. Since GMPEs are typically based on the so-called ergodic assumption, these differences are usually not modeled. Hence, PSHA results are biased because they do not include systematic source, path and site effects. By including the systematic source, path and site effects in fully non-ergodic GMPEs it is possible to reduce the value of the aleatory variability by about 30-40%. This requires the estimation of the systematic effects for every possible source/site combination, together with their epistemic uncertainty. If a non-ergodic GMPE is used in seismic hazard analysis, it is very important to propagate the epistemic uncertainty of the systematic effects to obtain the full hazard distribution. We build a non-ergodic GMPE for California, based on the assumption that the systematic source, path and site effects are spatially correlated. We calculate hazard for three sites in California and show the impact of incorporating the non-ergodic GMPE into seismic hazard analysis. For sites that have abundant data in their vicinity, the non-ergodic hazard changes compared to the ergodic on, while for sites with sparse date the mean hazard stays the same, but there is a large increase in the epistemic uncertainty range of the hazard.

Key Words
PSHA, Non-Ergodic

Kuehn, N. M., Abrahamson, N. A., & Walling, M. (2018, 08). Probabilistic Seismic Hazard Analysis in California Using Non-Ergodic Ground-Motion Prediction Equations. Poster Presentation at 2018 SCEC Annual Meeting.

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