Application and adaptation of global ground motion models to the eastern Caribbean Lesser Antilles

Kenneth S. Hudson, Jose M. Lockhart, Martin B. Hudson, & Jonathan P. Stewart

Published September 8, 2024, SCEC Contribution #13724, 2024 SCEC Annual Meeting Poster #189 (PDF)

Poster Image: 
The Lesser Antilles region of the eastern Caribbean experiences seismicity from shallow crustal earthquakes in active tectonic regions, subduction earthquakes (both interface and intraslab), and volcanic zone earthquakes. A regional study by Bozzoni et al. (2011) has formed the basis for probabilistic seismic hazard analyses (PSHA) in recent years. The ground motion models (GMMs) used in those PSHA studies were published between 1997 and 2008, were originally intended for global or regional (Japan) applications, and were not checked or calibrated using data from the eastern Caribbean region. Consequently, there is unquantified and therefore potentially large uncertainty associated with the application of those models to the region.
Our work aims to utilize regional data to test more recent global GMMs, from the NGA-West2 and NGA-Subduction projects, against eastern Caribbean regional data. We specifically aim to evaluate the effectiveness of the GMMs’ source, path, and site relationships for this region. We gather earthquake catalog data and associated recordings (including recording station properties), process the ground motions, compute intensity measures (IMs), and develop necessary source, path, and site metadata. We perform mixed effects residuals analyses for shallow crustal events using the Abrahamson et al. (2014), Boore et al. (2014), Campbell and Bozorgnia (2014), and Chiou and Youngs (2014) GMMs and for subduction events using the Kuehn et al. (2020) and Parker et al. (2022) GMMs. The residuals are partitioned into overall bias, event terms, and within-event residuals and are examined for trends with source, path, and site terms. Finally, adjustments to the GMM model coefficients and weighting for use in logic trees are recommended for the region.

Key Words
Seismic Hazard Analysis, Ground Motion Models

Citation
Hudson, K. S., Lockhart, J. M., Hudson, M. B., & Stewart, J. P. (2024, 09). Application and adaptation of global ground motion models to the eastern Caribbean Lesser Antilles. Poster Presentation at 2024 SCEC Annual Meeting.


Related Projects & Working Groups
Ground Motions (GM)