The Utah Geological Survey (UGS) updated the Quaternary Fault and Fold Database and Map of Utah on July 1, 2015, incorporating new data and a complete review of existing data through the end of 2013. Users of any Quaternary fault trace and related data acquired from the UGS or the Utah Automated Geographic Reference Center (AGRC) State Geographic Information Database (SGID) in the past are advised to use the updated database available from the AGRC SGID as the SGID10.GEOSCIENCE.QuaternaryFaults feature class. This single, comprehensive feature class will be periodically updated as new/updated data becomes available (anticipated several times per year) and replaces six previously available feature classes of variable completeness.

The database is a compilation of existing information on faults and fault-related folds considered to be potential earthquake sources (i.e., “active” faults and folds). The faults and folds contained in the database are those considered to have been sources of large earthquakes (about magnitude 6.5 or greater) during the Quaternary Period (past 2.6 million years); these geologic structures are the most likely sources of large earthquakes in the future. The database is intended to be a comprehensive source of the most current information available for characterizing active faults and folds in Utah for seismic-hazard analysis. This version of the database incorporates fault data from geologic maps and other documents formally published through 2013. In general, the database attribute conventions follow those of the Quaternary Fault and Fold Database of the United States maintained by the U.S. Geological Survey (USGS), which is infrequently updated.

More information on faults and earthquake hazards in Utah is available at geology.utah.gov/hazards/earthquakes-faults/utah-faults and geology.utah.gov/hazards/technical-information/paleoseismology-of-utah-series.