New Seismic Hazard Research Capabilities and Software Improvements in OpenSHA v25.4

Akash Bhatthal

Submitted September 7, 2025, SCEC Contribution #14464, 2025 SCEC Annual Meeting Poster #TBD

Over the past year, our research collaboration, including SCEC and USGS scientists and software developers, has made significant progress in enhancing SCEC’s computational tools and workflows to support the research community through the release of OpenSHA v25.4, an open-source, Java-based platform for conducting Seismic Hazard Analysis (SHA). This OpenSHA release supports several new and updated Earthquake Rupture Forecasts (ERFs), including the NSHM23 Western US (crustal only, excluding Cascadia) Branch Averaged ERF, the most recent USGS ERF for the Western U.S. It also includes the WGCEP UCERF3 Epistemic List ERF, which provides expanded epistemic uncertainties that enable plotting of fractiles and curves.

The OpenSHA Hazard Curve Control Panel now integrates a Generalized Conditional Intensity Measure (GCIM) option, which allows users to refine their selection of ground motions conditioned on specific earthquake scenarios.

OpenSHA software and model distribution have been improved by integrating the open-source GetFile software framework, which helps retrieve validated and versioned ERF data, decoupling data from release cycles and improving reliability.

To improve accessibility and transparency, we installed and configured OpenSHA-based UCERF3-ETAS simulations on a variety of HPC environments, including USC CARC Discovery, SDSC Expanse, TACC Stampede3, and TACC Frontera. We have also installed two UCERF3-ETAS apps into the Quakeworx science gateway. One of which is designed to configure and run simulations that generate aftershock probabilities following significant California earthquakes. This capability was used for several recent earthquakes, including the March 9, 2025 M4.1 Malibu event and the April 14, 2025 M5.3 Julian earthquake. In addition, we installed a tutorial app that was used during a SCEC Cybertraining workshop conducted in January 2025, where more than 60 early-career scientists and engineers participated.

We are planning several additional capabilities for future releases of OpenSHA, including an Intensity Measure Event Set Calculator, time-dependent earthquake forecast tools, improvements in software distribution tools, and documentation. This work will ensure that OpenSHA continues to provide essential capabilities that implement and deliver the best available science to the seismic hazard and seismic risk communities.

Key Words
OpenSHA,UCERF3-ETAS

Citation
Bhatthal, A. (2025, 09). New Seismic Hazard Research Capabilities and Software Improvements in OpenSHA v25.4. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Research Computing (RC)