OpenSHA

OpenSHA
Name	OpenSHA
Developer	Southern California Earthquake Center; University of Southern California researchers; U.S. Geological Survey
Initial release	2006
Programming language	Java
Operating system	Cross-platform
License	Open-source

OpenSHA

OpenSHA is an open-source seismic hazard analysis framework developed to enable probabilistic and deterministic seismic hazard calculations. It integrates earthquake rupture models, ground motion prediction, and epistemic uncertainty handling to support research and engineering assessments for regions such as California, Japan, and Chile. The project has been used by agencies including the U.S. Geological Survey, the Southern California Earthquake Center, and the California Geological Survey to inform building codes, risk assessment, and emergency planning.

Overview

OpenSHA provides a modular platform for computing seismic hazard through libraries that implement rupture generation, ground motion models, site response, and logic-tree frameworks. It supports probabilistic seismic hazard analysis (PSHA) workflows used by institutions like the Federal Emergency Management Agency, the National Institute of Standards and Technology, and the International Atomic Energy Agency for risk-informed decision making. The codebase, written in Java (programming language), is designed for interoperability with geospatial tools such as Geographic Information System packages used by the British Geological Survey and the Geological Survey of Japan.

History and Development

OpenSHA traces origins to collaborative efforts among researchers at the University of Southern California and the Southern California Earthquake Center in the mid-2000s, responding to methodological advances promoted by panels such as the Pacific Earthquake Engineering Research Center. Early development paralleled major seismic events studied by the Working Group on California Earthquake Probabilities and fed into hazard compilations for the 1994 Northridge earthquake aftermath. Funding and technical contributions have come from entities including the U.S. Geological Survey, the National Science Foundation, and the Los Alamos National Laboratory. Subsequent iterations incorporated models endorsed by consortia such as the Consortium of Organizations for Strong-Motion Observation Systems and protocols from the International Seismological Centre.

Architecture and Components

OpenSHA's architecture separates core services—rupture generation, seismic source characterization, ground motion prediction, and hazard integral computation—into interchangeable modules. The rupture modules implement catalogs and logic-tree branching akin to datasets maintained by the Global Centroid Moment Tensor Project and the International Seismological Centre. Ground motion modules wrap predictive equations developed by researchers associated with the Pacific Earthquake Engineering Research (PEER) group and contributors from Columbia University and Caltech. Supporting components interface with geodetic datasets from GNSS networks and focal mechanism compilations from the Centroid Moment Tensor Project.

Models and Methodologies

OpenSHA implements probabilistic seismic hazard analysis methods used in authoritative studies such as those by the Working Group on California Earthquake Probabilities and modeling approaches consistent with guidance from the NRC (National Research Council). It includes Gutenberg–Richter and characteristic recurrence models, as well as fault-rupture simulators influenced by work from Scholz, Beroza, and researchers at Scripps Institution of Oceanography. Ground motion prediction equations available in OpenSHA reflect empirical models developed by teams at U.S. Geological Survey, Pacific Earthquake Engineering Research Center, University of California, Berkeley, and University of Washington. Epistemic uncertainty is handled via logic trees and model-weighting schemes used by the Nuclear Regulatory Commission and adopted in studies for nuclear facilities.

Applications and Use Cases

OpenSHA has been applied to develop seismic hazard maps and site hazard curves for building codes influenced by the International Building Code and the ASCE 7 standard. Urban seismic risk assessments using OpenSHA connect to loss modeling frameworks employed by insurors such as Munich Re and Swiss Re and to resilience planning by municipal agencies like the City of Los Angeles. It has supported scenario modeling for historic earthquakes including the 1906 San Francisco earthquake and future rupture simulations for subduction zones examined after the 2011 Tōhoku earthquake and tsunami. Engineering projects for critical infrastructure—airports, ports, and power plants—have incorporated OpenSHA outputs in analyses aligned with protocols from the Federal Energy Regulatory Commission.

Community, Collaboration, and Governance

Development of OpenSHA involves a community of academics, governmental scientists, and industry practitioners from institutions such as the Southern California Earthquake Center, University of Southern California, California Institute of Technology, University of California, Berkeley, Massachusetts Institute of Technology, and the U.S. Geological Survey. Governance follows collaborative models similar to research consortia like the International Seismological Centre and standards bodies such as the American Society of Civil Engineers. Workshops, code sprints, and user meetings have been held alongside conferences including the Seismological Society of America meetings and the European Geosciences Union assembly to coordinate development and best practices.

Adoption and Impact on Seismic Hazard Practice

OpenSHA has influenced seismic hazard practice by enabling reproducible, transparent PSHA studies adopted by agencies such as the U.S. Geological Survey and the California Geological Survey. Its modular design has facilitated integration with hazard products from international organizations like the Global Seismic Hazard Assessment Program and has supported peer-reviewed studies published in journals associated with the American Geophysical Union and the Seismological Society of America. By providing a common platform, OpenSHA has promoted methodological consistency across projects undertaken by academic groups at Stanford University, University of Washington, and University of Southern California, and by consulting firms engaged by regulatory bodies such as the Nuclear Regulatory Commission.

Category:Seismology Category:Scientific software