About FaultLine Utah
Utah's earthquake information is good, but it's scattered across a half-dozen agencies, each speaking its own technical language. FaultLine Utah gathers the most useful parts, translates them into plain language for a specific address, and turns them into a short list of things to do.
We don't run our own hazard models. We present published, authoritative results from the Utah Geological Survey and the U.S. Geological Survey, and every result links to its source.
Our rules
- Translate, don't invent. We explain what the experts have published. We don't make new predictions.
- Every claim has a source. Each result card says where it came from.
- Bands, not false precision. Where the science is uncertain, we use plain categories, with the numbers one tap away under "Show the science."
- Experts review the science. We're recruiting a seismologist and a structural engineer to review this site's science and building guidance. Some features, like basin depth by address, stay off until they have.
Sources and dates
| What | Source | How we use it |
|---|---|---|
| Fault lines | Utah Geological Survey, Utah Quaternary Fault and Fold Database | Copied to this site; distances are computed in your browser. |
| Fault rupture study zones | Utah Geological Survey, surface-fault-rupture special study zones (Geologic Hazards Portal) | Copied to this site. |
| Liquefaction | Utah Geological Survey, liquefaction susceptibility (Geologic Hazards Portal) | Copied to this site. Used first wherever it has data. |
| Liquefaction (older) | Utah Geological Survey 1994 liquefaction-potential maps for Box Elder, Cache, Davis, Salt Lake, Utah and Weber counties, digitized by the Utah Geospatial Resource Center, CC BY 4.0 | Copied to this site. Used only where the newer map has no data, and labeled as older. Ranges such as "low to moderate" are scored at the higher end. |
| Building-code shaking | U.S. Geological Survey, Seismic Design web services (ASCE 7-22) | Asked live, with the location rounded to about 100 m. |
| 2020 Magna earthquake | U.S. Geological Survey, event page: ShakeMap and Did You Feel It? | Copied to this site. |
| Earthquake probabilities | Working Group on Utah Earthquake Probabilities (2016), UGS Miscellaneous Publication 16-3 | Quoted. |
| Basin research | Moschetti et al. (2021), SRL; Pang et al. (2020), GRL | Summarized on the Magna page. |
| Address search | Utah Geospatial Resource Center (UGRC) address locator, using the state's address points and road centerlines; OpenStreetMap Nominatim as a backup | Turns an address into a map point. |
| Base map | OpenFreeMap, © OpenMapTiles, data © OpenStreetMap contributors | Background streets and places. |
| Prep guidance | Be Ready Utah; Putting Down Roots in Earthquake Country; Ready.gov | The basis for Make a Plan. |
Hazard maps show what's been mapped, at the scale it was mapped (most UGS hazard maps are 1:24,000). Conditions on a single property can differ. Where a map has no data, that means no one has mapped it, not that there's no hazard.
Privacy
- We don't save the addresses you look up. Your location stays in your browser's address bar after the
#, a part browsers never send to a server. - To turn an address into a map point, your search text goes to UGRC's address locator, and to OpenStreetMap if UGRC can't find it. To get building-code values, a rounded location (about 100 m) goes to the USGS. The base map loads tiles for the area you're viewing.
- Fault, liquefaction, and Magna results are computed in your browser from files on this site, so those lookups send your location to no one.
- Make a Plan keeps your answers and checkmarks in this browser only. "Start over" erases them.
- No ads, no tracking cookies, no analytics that identify you.
What this site is, and isn't
FaultLine Utah is for education and preparedness only. It is not an engineering assessment, inspection, insurance determination, real-estate disclosure, or earthquake prediction. Talk to a licensed structural or geotechnical engineer about any specific building or site.
Utah does not have a public earthquake early warning system yet, and this site never sends alerts. For emergencies, call 911. For official guidance, follow Be Ready Utah and your city or county emergency manager.