Data sources & methodology

Every GeoScreen report is assembled from public agency datasets as of the date the report is run. We resolve an address to its parcel where county data is available, then check that parcel against each dataset below. Every finding cites the agency source behind it.

The datasets we screen

• Fault rupture

  Refreshed quarterly

  California Geological Survey — Alquist-Priolo Earthquake Fault Zones and mapped fault traces.

• Seismic & liquefaction

  Refreshed quarterly

  California Geological Survey — Seismic Hazard Zones (liquefaction Zones of Required Investigation).

• Earthquake-induced landslide

  Refreshed quarterly

  California Geological Survey — Seismic Hazard Zones (earthquake-induced landslide zones) and mapped landslide inventory.

• Slope & terrain

  Refreshed as the agency publishes

  U.S. Geological Survey — 3DEP elevation data, from which slope across the parcel is derived.

• Wildfire severity

  Refreshed quarterly

  CAL FIRE — Fire Hazard Severity Zones (State and Local Responsibility Areas).

• Flood

  Refreshed monthly

  FEMA — National Flood Hazard Layer (NFHL) flood hazard zones.

GeoScreen reports are a preliminary screening assembled from public agency data. They are not a professional geologic report, not a Natural Hazard Disclosure (NHD), and not a substitute for a site-specific investigation by a licensed geologist. A report reflects what the agency maps show as of the date it was run; agency data can change, and a screening never replaces a professional opinion about a specific property.