West Napa Fault

The West Napa Fault is a 57 km (35 mi) long geologic fault in Napa County, in the North Bay region of the San Francisco Bay Area in northern California.

It is believed to be the northern extension of the Calaveras Fault in the East Bay region.

[1] The fault was discovered in 1976 by Gene Boudreau, a ground water drilling specialist from Sebastopol.

[2] In 2023 there was data showing that the West Napa Fault is actually nine miles longer than previously known.

[5] The epicenter for the 2000 Yountville earthquake which occurred on September 3, 2000, is also near the West Napa Fault.

The reported epicenter of the 2014 South Napa earthquake was located beneath the Napa Valley Marina