Fault Displacement Hazard Initiative research program

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.