Development of a Peak Spectral Displacement Ground-motion Model Using Global HR-GNSS Observations
Description:
Ground motion models (GMMs) are a key tool in the estimation of seismic hazard for engineering, describing the relationship between ground-motion intensity and predictive parameters such as magnitude and distance. GMMs most often utilize higher-frequency based intensity metrics such as Peak Spectral Acceleration (PSA). Peak displacement-based metrics are less common, as most intensity measures are derived from acceleration or velocity measurements from seismometers, which, as inertial sensors, pose uncertainties in lower-frequency measurements. However, these metrics are still important to assessing seismic hazard across the full frequency range generated from earthquake rupture. Advancements in high-rate global navigation satellite systems (HR-GNSS) have allowed for accurate measurements of dynamic seismic displacement directly up to 20Hz, and are now the basis of some peak ground displacement (PGD) GMMs. We present work towards developing a ground motion model for peak spectral displacement (PSD), using HR-GNSS observed waveforms. We develop GMMs for PGD as well as PSD, of interest for structures sensitive to low frequency energy, such as base isolators and long span bridges (among others).
We produce an expanded catalog of HR-GNSS waveform data, combining data from "DeGrande, J., & Crowell, B. (2023). Improvement in GNSS Magnitude Estimation Performance with a Combined PGD-PGV Scaling Law for Earthquake Early Warning. AGU23." with the Ruhl et al. (2018) dataset. The resulting catalog contains global observations from 75 M5+ earthquakes (2003 –2021). We compute the peak spectral displacements using a multi-taper method and perform a mixed effects regression on the resulting values to create our model. With this model we present, we will also examine the relative sensitivities of lower-frequency displacement-based metrics to source and site properties, to establish the most robust final functional form for these intensity measures.
Session: Accuracy and Variability of Physics-based Ground Motion Modeling [Poster]
Type: Poster
Date: 4/15/2025
Presentation Time: 08:00 AM (local time)
Presenting Author: Braden
Student Presenter: Yes
Invited Presentation:
Poster Number: 85
Authors
Braden Hensley Presenting Author Corresponding Author bhensley@uoregon.edu University of Oregon |
Valerie Sahakian vjs@uoregon.edu University of Oregon |
Jensen DeGrande jdegran@uw.edu University of Washington |
Brendan Crowell crowell.97@osu.edu Ohio State University |
Diego Melgar dmelgarm@uoregon.edu University of Oregon |
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Development of a Peak Spectral Displacement Ground-motion Model Using Global HR-GNSS Observations
Session
Accuracy and Variability of Physics-based Ground Motion Modeling