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Published November 1, 2025 | Version Published
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Fault Displacement Hazard Initiative research program

Creators

  • 1. ROR icon University of California, Los Angeles
  • 2. ROR icon University of California, Berkeley
  • 3. Autorité de Sûreté Nucléaire et de Radioprotection, Fontenay-aux-Roses, France
  • 4. ROR icon University of Chieti-Pescara
  • 5. California Geological Survey, Sacramento, CA, USA
  • 6. ROR icon California Department of Transportation
  • 7. Pacific Gas & Electric Company, San Francisco, CA, USA
  • 8. ROR icon California Institute of Technology
  • 9. ROR icon California Polytechnic State University
  • 10. ROR icon Rina Services (Italy)
  • 11. GeoPentech, Inc., Santa Ana, CA, USA
  • 12. ROR icon University of Vienna
  • 13. ROR icon National Institute of Geophysics and Volcanology

Abstract

This paper provides an overview of the Fault Displacement Hazard Initiative (FDHI). The FDHI is a community-based and multi-year research initiative with the goals of developing: (a) a comprehensive empirical database of surface fault displacement measurements and mapped ruptures, and (b) a suite of next-generation fault displacement predictive models. The database was developed by systematically collecting worldwide data from professional literature, followed by an extensive review and quality assurance process. The FDHI database contains 75 surface-rupturing earthquakes ranging from moment magnitude M 4.9 to 8.0 including data from strike-slip, reverse/reverse-oblique, and normal/normal-oblique faulting events. As part of the FDHI Program, employing the database, four new fault displacement models (FDMs) were developed. The FDMs predict principal or aggregate surface displacement, where aggregate is the combined displacement across principal and distributed ruptures. Two models were developed for all styles of faulting, while the other two are for reverse or strike-slip faulting. The new models include improved magnitude scaling and aleatory variability modeling. Compared with pre-existing models, average displacements in the new models are about 40% larger for M ~7, but smaller for lower and higher magnitudes. In addition, the new models predict significantly smaller displacement at low probability of exceedance. Besides the core FDHI tasks, in this article we also provide an overview of other parallel projects completed in coordination with the FDHI Program.

Copyright and License

© 2025 by Earthquake Engineering Research Institute.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Financial support for this work was provided by the Pacific Gas & Electric Company, California High-Speed Rail Authority, California Department of Transportation, Southern California Gas Company, Los Angeles Department of Water and Power, and California Energy Commission. The California Geological Survey, United States Geological Survey, Southern California Earthquake Center, California Institute of Technology, and Lettis Consultants International are partners in the FDHI Program. The support of these organizations is appreciated. The opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect those of the aforementioned organizations.

Data Availability

The FDHI database of 75 worldwide surface-rupturing earthquakes is available in Sarmiento et al. (2024). All four FDHI models have been coded in Python and Excel and are publicly available at https://doi.org/10.5281/zenodo.13552790 and https://doi.org/10.5281/zenodo.14231829, respectively. An overview of the Python and Excel tools can also be found at https://girs.squarespace.com/nhr3/products/fdhi. Figures 3 and 4 were produced using version 1.0.0 of the Python package. Additional documentation supporting this article is available in the multiple project papers cited above.

Additional details

Related works

Is supplemented by
Dataset: 10.5281/zenodo.13552790 (DOI)
Dataset: 10.5281/zenodo.14231829 (DOI)
Software: https://girs.squarespace.com/nhr3/products/fdhi (URL)

Funding

PG&E Corporation (United States)
CA HighSpeed Rail Authority
California Department of Transportation
Southern California Gas Company
Los Angeles Department of Water and Power
California Energy Commission

Dates

Submitted
2025-04-06
Accepted
2025-05-19
Available
2025-08-11
Published online

Caltech Custom Metadata

Caltech groups
Division of Engineering and Applied Science (EAS), Division of Geological and Planetary Sciences (GPS)
Publication Status
Published