UCLA

The Next Generation Attenuation (NGA)-West3 Program database builds upon that of NGA-West2 for shallow crustal earthquakes in active tectonic regimes to provide a robust data set to develop the next iteration of NGA ground motion models (GMMs). Researchers from Italy, Japan, New Zealand, Taiwan, United Arab Emirates, and the United States, amongst others, have collaborated to develop consistently processed data with uniform metadata from the respective regions, with data for other regions drawn from literature (e.g., Greece, Japan, and Türkiye). Over 80,000 three-component ground motions from 632 events with magnitudes generally greater than 4.0 across the Western United States (mostly in California) have been newly added, and the total database size is over 175,000 ground motions (generally three-component except for two-component records from KiK-Net stations in Japan). The database is being used by several teams of NGA GMM developers and will be publicly released sometime in 2025 when the NGA-West3 GMMs have been drafted.