Integration of Maximum Magnitude Forecast and Ground Motion Prediction for Real-Time Seismic Hazard Assessment at Utah FORGE

Abstract

Accurate ground motion prediction is essential for assessing the potential impact of induced seismicity during fluid injection in enhanced geothermal systems (EGS). Building on our maximum magnitude (Mmax) forecasting framework, we integrated Mmax predictions with ground-motion prediction equations (GMPEs) to evaluate spatial and temporal variations in seismic hazard at the Utah FORGE site. The approach combined the predicted Mmax values with GMPEs that account for local geological and site effects, including shallow time-averaged shear-wave velocity (Vs30) and epicentral distance. By dynamically linking source-level forecasts to site-level motion estimates, the model provided updated predictions of Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) at nearby population centers and infrastructure nodes. Preliminary results from the 2022 and 2024 FORGE stimulations indicated that incorporating evolving Mmax forecasts improved the reliability of PGA and PGV estimates under changing injection and post-injection conditions. This integrated framework provides a pathway to real-time, data-informed seismic hazard assessment in EGS operations, enhancing risk mitigation and supporting the refinement of traffic-light protocols.