Ground‐Motion Characterization for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands

We develop the ground‐motion characterization (GMC) for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands (NSHM‐PRVI) for earthquakes in active crustal, subduction interface, and subduction intraslab regimes. Using ground‐motion models (GMMs) from the Next‐Generation Attenuation (NGA)‐West2 and NGA‐Subduction projects, the GMC is parameterized by scaled‐backbone models for median ground motions and by independent logic trees of aleatory variability. We introduce several novel GMC features into the U.S. NSHM: (1) use of regional ground‐motion data for modeling median ground motions; (2) development of scaled‐backbone models for median ground motions; and (3) development of…