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An online map of faults (Quaternary Fault and Fold Database of the United States) that includes California is in the Faults section of the Earthquake Hazards Program website. Choose the Interactive Fault Map, or download KML files and GIS shapefiles from the links on the page.

Sep 27, 2022 · The various colors and line types indicate different ages of the most recent earthquakes on the fault and how well the location of the fault is constrained. For more details, see Quaternary Faults.Map showing Quaternary faults in the western U.S. and Pacific Ocean.

Find and download CGS Earthquake Zones of Required Investigation maps and reports, including fault zones, liquefaction zones, and earthquake-induced landslide zones.

Though plate motion is constant, faults get stuck, building up strain until they break and release the strain as an earthquake. This map shows the locations and activity of significant faults in California, categorized by the rate they move and can produce earthquakes. The maximum size of an earthquake is related to the length of the fault.

The Alquist-Priolo Act requires the State Geologist (CGS) to establish earthquake fault zones around the surface traces of active faults and to issue appropriate maps. CGS has identified earthquake fault zones in thirty-seven California counties, affecting more than one hundred cities.

Nov 21, 2024 · The California Earthquake Hazards Zone Application ("EQ Zapp") is an online map that allows anyone with a computer, tablet or smartphone to conveniently check whether a property is in an earthquake hazard zone.

Apr 11, 2022 · The map shows locations of known faults that can be portrayed at 1:750,000 scale and indicates the latest age when displacements took place, according to available data. The displacements may have been associated with earthquakes or may have been the result of gradual creep along the fault surface.

Mar 13, 2025 · The 2010 Fault Activity Map of California presents a much more detailed depiction of faults in California than previous versions. In order to preserve as much of the original detail as possible, most faults active in the Quaternary (2.6 Ma) were digitized from their original sources (geologic maps ranging from 1:12,000 to 1:250,000 scale).

Search Earthquakes Near You (Relative2Me). Brown lines are known hazardous faults and fault zones. Magnitude = ? for new earthquakes until a magnitude is determined (takes 4-5 minutes). Maps are updated within 1-5 minutes of an earthquake or once an hour.