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Significance of Non-ergodic Ground Motion Models in Seismic Loss Assessment

Description: 

The substantial increase in ground motion records in California over the past decades has enabled the development of non-ergodic ground motion models (NEGMMs). However, the implications of NEGMMs for structural and infrastructural loss assessment have not yet been thoroughly examined. This study is among the first to investigate the impact of NEGMMs on site-specific seismic hazard and losses due to scenario earthquakes in California. Two sets of ground motion models are employed: a state-of-the-art NEGMM and a conventional ergodic model. Response spectra for scenario earthquakes are generated for two hypothetical assets—a bridge and a building—located at distinct sites in the San Francisco Bay Area, with expected loss ratios calculated using the HAZUS estimation methodology. By accounting for systematic variations in source, path, and site effects, non-ergodic response spectra exhibit reduced aleatory variability compared to their ergodic counterparts, while median ground motions can either increase or decrease relative to the ergodic model. As a result, the adoption of NEGMMs may increase or decrease site-specific hazard and loss. Furthermore, our preliminary loss evaluation results indicate that incorporating the non-ergodic model moderately increases bridge losses but significantly decreases building losses. These findings underscore the potential for NEGMMs to enhance seismic hazard and risk assessments. Further work should explore their implications at the portfolio level, particularly for stochastic event sets.

Session: Testing, Testing 1 2 3: Appropriate Evaluation of New Seismic Hazard and Risk Models [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Emel

Student Presenter: No

Invited Presentation: 

Poster Number: 69

Authors