Assessing the Applicability of the Use of Simulation Results in Non- Ergodic GMMs for Areas Without Empirical Data
Description:
This study examines ground-motion simulations from the Southern California, Pacific Northwest, Utah, and Japan regions to evaluate the spatial correlation and variance of nonergodic path and site terms associated with ground motions from crustal and subduction events. The spatial distribution of the nonergodic site and path terms derived from the simulations was estimated using the varying coefficient model (VCM) within the geographical region of the simulations. The nonergodic terms obtained from these simulations demonstrate larger variations in the path and site terms compared to those derived from empirical data, and notable discrepancies exist between the median nonergodic terms for simulation and empirical data sets. Part of the discrepancy is due to the different spatial sampling for the simulation and empirical data sets, with much finer spatial coverage in the simulation data sets. The nonergodic terms from the simulations fall within the epistemic uncertainties range of the empirical results, indicating that the simulations are not rejected by the empirical data and that the integration of simulation results into the ground motion model has the potential to enhance predictive accuracy in regions where empirical data is limited. Furthermore, the nonergodic terms derived from simulations exhibit significantly higher spatial resolution than those obtained from empirical data, highlighting a key advantage of utilizing simulation-based nonergodic terms. The subsequent phase of this research will involve further investigations that evaluate the three-dimensional velocity structures and geological data to assess the appropriateness of including simulation results in seismic hazard applications, particularly in regions with insufficient empirical data.
Session: Challenges and Opportunities in Constraining Ground-motion Models from Physics-based Ground-motion Simulations - II
Type: Oral
Date: 4/17/2025
Presentation Time: 11:30 AM (local time)
Presenting Author: Chih-Hsuan
Student Presenter: No
Invited Presentation:
Poster Number:
Authors
Chih-Hsuan Sung Presenting Author Corresponding Author karensung@berkeley.edu University of California, Berkeley |
Norman Abrahamson abrahamson@berkeley.edu University of California, Berkeley |
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Assessing the Applicability of the Use of Simulation Results in Non- Ergodic GMMs for Areas Without Empirical Data
Category
Challenges and Opportunities in Constraining Ground-motion Models from Physics-based Ground-motion Simulations