A man photographs damage to a post office following an earthquake in Napa, Calif. on Aug. 24, 2014.

Cellar workers clean up after a number of barrels toppled following an earthquake at the Saintsbury winery on Aug. 24, 2014 in Napa, Calif.

Barrels filled with Cabernet Sauvignon are toppled on one another following an earthquake at the B.R. Cohn Winery barrel storage facility on Aug. 24, 2014 in Napa, Calif.

Skateboarder Chris Young, 22, launches himself off a buckled sidewalk following an earthquake in Napa, Calif. on Aug. 24, 2014.

A youngster rides his scooter over a sidewalk buckled by an earthquake on Aug. 24, 2014 in Napa, Calif.

A cracked section of roadway is shown in the Carneros district following an earthquake on Aug. 24, 2014, in Napa, Calif.

Pedestrians stop to examine a crumbling facade at the Vintner's Collective tasting room in Napa, Calif. on Aug. 24, 2014.

A boy examines cars trapped beneath a collapsed carport at Charter Oaks apartments in Napa, Calif., following an earthquake Sunday, Aug. 24, 2014.

@CamLucchesi posted this photo to Instagram with the caption "Cali Quakes" on Aug. 24, 2014.

Laura Anthony posted this photo to Twitter with the caption "Napa couple looks at the remains of mobile home they own with their son. One of 4 completely destroyed by fire" on Aug. 24, 2014.

A mailbox is all that remains of one of four mobile homes which were destroyed in a gas fire Sunday, Aug. 24, 2014, at the Napa Valley Mobile Home Park, in Napa, Calif.

A Napa County firefighter sprays foam on hot spots from a fire at a mobile home park following a reported 6.0 earthquake on August 24, 2014 in Napa, Calif.

Elvira Balbazar, an employee at the 3J's Oriental Market cleans up after an earthquake Sunday, Aug. 24, 2014, in American Canyon, Calif.

Police tape blocks the entrance to the damaged main post office following an earthquake Sunday, Aug. 24, 2014, in Napa, Calif.

Gurbeer Singh cleans up merchandise which fell due to an earthquake at a 7-Eleven store Sunday, Aug. 24, 2014, in American Canyon, Calif.

Jeremy Cowell posted this photo to Instagram on Aug. 24, 2014 with the caption "Napa is in a some sad shape. So sad!!!"

Bottles of olive oil and vinegar sit on the floor of a business damaged by a reported 6.0 earthquake, Aug. 24, 2014, in Napa, Calif.

@lizliz3000 posted this photo to Instagram with the caption "napa earthquake" on Aug. 24, 2014.

People look at a damaged building with a top corner exposed following an earthquake Sunday, Aug. 24, 2014, in Napa, Calif.

Bricks are in the street after a building was damaged during an earthquake in Napa, Calif., Aug. 24, 2014.

A building is seen destroyed following a reported 6.0 earthquake, Aug. 24, 2014, in Napa, California. A 6.0 earthquake rocked the San Francisco Bay Area shortly after 3 am on Sunday morning.

This photo from Alexander Simenstad shows the fire department on the scene after a reported 6.0 earthquake in Napa, Calif., Aug. 24, 2014.

People wearing bathrobes walk down a street following a reported 6.0 earthquake, Aug. 24, 2014, in Napa, Calif. The earthquake rocked the San Francisco Bay Area shortly after 3 am on Sunday morning.

Luke Magnini posted this photo to Instagram with the caption "A nice warm welcome to California... 6.1 with the epicenter in Napa Valley." The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.

Lyall Davenport posted this photo to Twitter with the caption "Building destroyed in napa #earthquake." The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.

Emily Massimi posted this photo to Twitter with the caption "Damage from #earthquake to my sister's kitchen in #napa. Thankfully nothing to major in this room of her apartment." The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.

@gbabydolls posted this photo to Instagram with the caption "this is why we can't have nice things #earthquake #imok #6.0magnitude I wasn't home." The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.

@setimothy posted this photo to Instagram with the caption "6.0 #earthquake 24 Aug 14 323am #napa #California. #Happy birthday #SHELBY." The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.

Jessette Porter posted this photo to Twitter with the caption "Napa hall of justice damage #earthquake" The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.

@Murdrae posted this photo to Instagram with the caption "#napa #earthquake #fire hope everyone is okay." The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.

Bryan Metcalf posted this photo to Twitter with the caption "I just escaped the #Napa #earthquake. Everything fell around me and not on me." The U.S. Geological Survey says a 6.0 magnitude earthquake struck northern California, Aug. 24, 2014.