OpenSHA fault system tools for building, reproducing, and computing and disaggregating hazard from fault-system-solution earthquake rupture forecasts

Kevin R. Milner

Published September 8, 2024, SCEC Contribution #13892, 2024 SCEC Annual Meeting Poster #204

OpenSHA Fault System Tools (FST; https://github.com/opensha/opensha-fault-sys-tools) is a suite of command line utilities related to fault-system-solution earthquake rupture forecasts, such as those developed for the western United States as part of the 2023 update to the National Seismic Hazard Model (NSHM23). It is developed as part of OpenSHA, an open-source seismic hazard analysis platform. FST allows advanced users to reproduce NSHM23 inversion results or build their own models following similar approaches. Steps to build a fault-system-solution model include defining faults in a simple GeoJSON format, dividing those faults into subsections, building a rupture set of unique combinations of those subsections using a rupture plausibility model (often including multi-fault ruptures), and inverting for the rates of those ruptures satisfying fault slip rate and magnitude-frequency distribution constraints.

FST also includes tools for efficient calculation and disaggregation of hazard curves for fault-system-solution models. Calculations are run in parallel and can be batch processed without the need to manually select parameters in a graphical user interface. Disaggregation options include traditional magnitude and distance disaggregation, as well as disaggregation of hazard curves by source type and maps of contributing sources. Hazard curves and disaggregation results are written in simple comma-separated-value files, and rich Markdown and web-based reports with plots are generated.

Key Words
OpenSHA, NSHM23, ERF, PSHA

Citation
Milner, K. R. (2024, 09). OpenSHA fault system tools for building, reproducing, and computing and disaggregating hazard from fault-system-solution earthquake rupture forecasts. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Forecasting and Predictability (EFP)