Group B, Poster #190, Ground Motions
Empirical Assessment of Site and Basin Response in the Pacific Northwest via Testing Site-Response Models for Different Tectonic Regimes
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Poster Presentation
2023 SCEC Annual Meeting, Poster #190, SCEC Contribution #13238 VIEW PDF
MMs improved predictions of basin response in the California Great Valley but did not perform as well in the shallow Reno-Sparks basins or the more geologically complex Portland-Tualatin basins.
We first analyze basin response by compiling and processing regional ground-motion data and performing residuals analyses and mixed-effects regressions. We build upon the study in Portland by (1) improving VS30 characterization of stations that recorded ground motions by using measured VS30 values where available or alternative proxy-based VS30 prediction models other than topographic slope and (2) computing GMM estimates with both an NGA-Subduction empirical site-response model for the PNW and the site-response model built into the NGA-West2 GMMs for shallow crustal events. If the site-response models are shown to be independent of earthquake source type, we can reduce uncertainty in ground-motion predictions by replacing site-response models in ergodic GMMs with region-specific site-response models developed using a subset of potential earthquake sources. This would result in improved ground-motion estimation in regions within national-scale seismic hazard studies that generally employ global ergodic site-response models at all locations within a tectonic regime.
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We first analyze basin response by compiling and processing regional ground-motion data and performing residuals analyses and mixed-effects regressions. We build upon the study in Portland by (1) improving VS30 characterization of stations that recorded ground motions by using measured VS30 values where available or alternative proxy-based VS30 prediction models other than topographic slope and (2) computing GMM estimates with both an NGA-Subduction empirical site-response model for the PNW and the site-response model built into the NGA-West2 GMMs for shallow crustal events. If the site-response models are shown to be independent of earthquake source type, we can reduce uncertainty in ground-motion predictions by replacing site-response models in ergodic GMMs with region-specific site-response models developed using a subset of potential earthquake sources. This would result in improved ground-motion estimation in regions within national-scale seismic hazard studies that generally employ global ergodic site-response models at all locations within a tectonic regime.
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Citation: Ahdi, S. K., Aagaard, B. T., Moschetti, M. P., Boyd, O. S., Parker, G. A., & Stephenson, W. J. (2023, 09). Empirical Assessment of Site and Basin Response in the Pacific Northwest via Testing Site-Response Models for Different Tectonic Regimes. Poster Presentation at 2023 SCEC Annual Meeting.
Keywords: site response, ground motion models, shallow crustal, subduction zones
Relevant SCEC Themes:
Probabilistic Seismic Hazard Analysis
Velocity and Rheology of Basin Sediments
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