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The USGS 2025 Puerto Rico and U.S. Virgin Islands Earthquake Rupture Forecast

Description: 

We present the preliminary 2025 U.S. Geological Survey (USGS) time-independent earthquake rupture forecast (ERF) for Puerto Rico and the U.S. Virgin Islands (PRVI). This model updates the prior 2003 ERF and includes expanded geologic and seismologic input data, as well as methodological improvements based on the 2023 National Seismic Hazard Model (NSHM23) for the conterminous U.S. Development of the ERF is overseen by a 16-member participatory review panel. The model is expected to be released in December 2025.

The crustal on-fault portion of the ERF includes substantial updates to the fault inventory (increasing from 3 to 35 fault sections) and a new geologic deformation model that captures uncertainties in fault slip rates. We use the inversion approach to solve for rupture rates matching those slip rate data in an interconnected fault-system following the methodologies established for the western U.S. in NSHM23. The statistical seismology model largely follows the methods used in NSHM23, but includes an updated rate uncertainty estimation method that is more appropriate for regions where completeness magnitude is near or above the minimum magnitude considered for hazard calculations (as is the case for PRVI). We find that earthquake activity rates calculated for crustal faults exceed best-estimate extrapolations from observed seismicity, i.e., there is a “bulge” in the regional magnitude-frequency distribution. This indicates a potential inconsistency between the data, assumptions, and/or methodologies used for the crustal fault and statistical seismology models. This is an outstanding issue that warrants further investigation in future models, including identifying any biases in fault slip rates and regional seismicity rates. The ERF for subduction sources also uses the fault-system inversion methodology to solve for rates of large interface ruptures and match slip rate data. This is a first for U.S. subduction ERFs, and paves the way for future updates for Alaska and Cascadia. It includes uncertainties in coupled interface geometry and slip rates, rupture scaling, and b-value.

Session: Advancing Seismic Hazard Models [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Kevin

Student Presenter: No

Invited Presentation: 

Poster Number: 58

Authors