The Largest Quake Since Loma Prieta
At 3:20 AM on August 24, 2014, a magnitude 6.0 earthquake struck the Napa Valley, centered about 6 miles south of Napa. It was the largest earthquake to hit the Bay Area since the 1989 Loma Prieta event.
The earthquake woke residents throughout Northern California, from Sacramento to San Francisco. Over 200 people were injured, and one person died from heart-related causes during the event.
Damage to Wine Country
The earthquake caused significant damage to the historic downtown Napa area. Many older, unreinforced masonry buildings suffered partial or complete collapse. The famous Napa wineries experienced substantial losses, with an estimated $80 million in damaged wine barrels alone.
Fires broke out in multiple locations from broken gas lines, destroying several mobile homes. Over 100 homes were red-tagged as unsafe for occupancy.
The West Napa Fault
The earthquake occurred on the West Napa Fault, a previously less-studied fault that runs north-south through the region. The event produced approximately 12 kilometers of surface rupture with up to 46 centimeters of displacement.
This earthquake served as a reminder that the Bay Area has many active faults beyond the well-known San Andreas and Hayward faults.
Aftershock Sequence
The South Napa earthquake was followed by a significant aftershock sequence, with over 250 aftershocks recorded in the first two weeks. The largest aftershock measured magnitude 3.9.
Economic Impact
Total economic losses were estimated between $400 million and $1 billion, including both direct damage and business interruption. The earthquake had a significant impact on Napa's tourism-dependent economy, particularly during the critical harvest season.