The U.S. Geological Survey 2025 Puerto Rico and U.S. Virgin Islands Time-Independent Earthquake Rupture Forecast

ABSTRACT We present the 2025 U.S. Geological Survey Puerto Rico and U.S. Virgin Islands (PRVI) time-independent earthquake rupture forecast (ERF), developed for the 2025 update to the National Seismic Hazard Model (NSHM) for PRVI. The updated ERF improves upon a prior model from 2003, including an expanded fault inventory with slip-rate estimates, updated seismicity catalogs, and refined subduction zone geometries and deformation models. It applies the fault-system inversion methodology to solve for rates of ruptures on modeled faults, adapted from the 2023 NSHM (NSHM23) for the western United States, including the first application of the inversion to model rates on a U.S. subduction interface. Off-fault and intraslab seismicity are constrained by observed seismicity and use updated methods developed for NSHM23. Uncertainties in model components are substantial, and the ERF represents epistemic uncertainties through a comprehensive logic tree consisting of 1.7 billion logic-tree branches combined across all sources.