Locate a site. Explore nearby faults.
Measure the distance in between.
Approximate distances · location accuracy
Fault lines represent mapped interpretations, not surveyed positions. USGS warns that zooming in can exceed the accuracy of the fault data. Accuracy varies with the source mapping and trace type.
This KMZ does not supply numerical positional uncertainty for each trace, so a defensible ± km or mi range cannot be calculated. “Well constrained” and mapped scale are context, not a numeric error bound. Decimal places show calculation precision, not location accuracy. Address or selected-point uncertainty adds further error.
Use these distances for preliminary screening. Consult the original fault report and appropriate site-specific investigation for engineering or regulatory decisions.
USGS fault-map accuracy guidance ↗About the data & measurements
Source: U.S. Geological Survey (USGS), Quaternary Fault and Fold Database of the United States, with California Geological Survey contributions. The supplied California Faults.kmz is a subset filtered to California faults. Classes come from its “Fault Class” attribute, not line colors. Unclassified traces are excluded. Distances are horizontal, spherical great-circle distances to the nearest mapped line segment, using all original vertices. They are not driving distances or distances to a fault at depth.
Database citation: U.S. Geological Survey, 2020, Quaternary Fault and Fold Database for the Nation, accessed October 15, 2026, doi:10.5066/P9BCVRCK. This citation identifies the parent database; the supplied KMZ download date and version were not provided.
The file contains historical review dates. Results describe this dataset and do not establish current regulatory fault zones or site safety.
Map tiles require internet. As you type, address text is sent to Esri for temporary address matches, with a California search area and preference near the Sunnyvale office. Photon (Komoot) and US Census provide fallback lookups. Confirm the displayed city before selecting an address. Coordinate calculations run in your browser.
Geocoder documentation ↗