The most likely faults that are likely to produce strong ground shaking in Napa County include the Northern Hayward/Rodgers Creek in the west, the Maacama in the northwest, the Hunting Creek-Berryessa in the north, the Green Valley in the southeast and the West Napa in the south central. The Concord Green Valley and the West Napa Fault are the only two major faults that pass through County boundaries.
The combined probability of a major quake on one of these major faults is 63% over the next thirty years. Most of Napa County’s resources and population are in the Napa Valley floor, which consists of alluvial soils that enhance and amplify the shaking from earthquakes. In 2000, a magnitude 5.0 earthquake struck an unmapped fault just west of the West Napa Fault with an epicenter near Yountville and caused significant damage in the city of Napa.
Napa County Hazard Map
Locate the area where you live and click to determine the most damaging earthquake scenario for your area.
Source: USGS, 2013.