California Earthquake Hazard Profile
Hazard Data · Model Version 2.5
Overview
California experiences significant seismic activity along the San Andreas Fault system and numerous subsidiary faults including the Hayward, Calaveras, and San Jacinto faults. The state has the highest seismic hazard in the contiguous United States according to the USGS National Seismic Hazard Model (NSHM 2023). FEMA records show California accounts for the majority of US earthquake-related federal disaster declarations.
In the Historical Record
Counted from the records this platform holds. A figure is shown only where the underlying dataset could be read.
County by County in California
What federal records show has happened in each county: storms, disaster declarations and flood insurance claims. The counties below have the longest NOAA storm records in California.
Notable Historical Events
Hazard Scoring Approach
Calchis computes a Calchis Hazard Score (0–10) for earthquake hazard at any US address. The score is composed of weighted sub-components derived from federal data sources and published research. All score components are transparent and returned in API responses.
These are hazard scores — physical intensity likelihood only. They do not include property exposure or vulnerability data. We never call a hazard score a risk score. See the full methodology for scoring details.
Analyze Your Address
Enter any California address to see location-specific earthquake hazard scoring with full methodology transparency.
Open Live Map — CaliforniaData Sources
Related
Monitoring earthquake exposure in California?
This page is a state-level profile. Calchis scores individual addresses, tracks live earthquake events against your own locations, and alerts you when one approaches them.
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Calchis Hazard Score — derived from federal and academic sources listed above. Property exposure data not included. Not a substitute for professional actuarial assessment. Decision-support intelligence — not a primary alerting or dispatch system. Verify against official sources.