— -- Northern California was shaken awake Sunday by its strongest earthquake in 25 years, a jolt that damaged historic buildings and hurt dozens of people, including a 13-year-old critically injured by a crumbling fireplace.
California Gov. Jerry Brown declared a state of emergency after the South Napa Earthquake, which struck about 3:20 a.m. local time, according to the U.S. Geological Survey. Its epicenter was located about six miles south-southwest of Napa, California, and 51 miles west-southwest of the state capital, Sacramento. Officials have variously referred to the earthquake's magnitude as 6.0 and 6.1.
The earthquake was the largest one to shake the Bay Area since the 1989 6.9-magnitude Loma Prieta Earthquake. Dozens of aftershocks followed.
Pacific Gas and Electric Company initially showed more than 15,000 customers without power, primarily in Napa, Sonoma and Santa Rosa Counties.
Several buildings in Napa were damaged or on fire in the wake of the earthquake, ABC News station KGO in San Francisco reported. Napa City Manager Mike Parness said at least 15 buildings will need to be inspected or repaired before they can be occupied again.
"We had multiple structure fires that we've been dealing with -- a total of about six," John Callanan of the Napa Valley Fire Department told reporters. "In one of those incidents, it involved approximately six mobile homes together, so that was one single incident. Four of the six are completely damaged. The other two have suffered some major damage."
Callanan also said firefighters have received more than 100 calls from people who smelled natural gas.
"Our resources are exhausted as far as quantity of on-duty personnel," he said.
Dozens of water main leaks were also reported, although city officials said the water was safe to drink.
At least 120 people were treated at Queen of the Valley Medical Center in Napa, hospital officials told ABC News. Only a handful of patients needed to be hospitalized.
Six of those people suffered critical injuries, including the child hurt by the fireplace, who was flown to UC Davis Medical Center for further treatment, said hospital president Walt Mickens. The child was in stable condition.
All schools in the Napa Valley Unified School District will be closed Monday. Justin Siena High School will also be closed.
Historic buildings damaged by the earthquake included Sam Kee Laundry, Goodman Library and the Napa County Courthouse, the city said, adding that two commercial buildings also suffered severe damage.
Napa County Supervisor Bill Dodd said he believed the county courthouse had been retrofitted for earthquakes.
"I've been through a few of these and I've never seen anything like this, particularly in downtown Napa," Dodd said, according to ABC News Radio. "The county building is just in total disrepair, and they've moved it down to the sheriff's office -- so that's where the coordinating all the emergency services for the county."
President Obama was briefed on the earthquake this morning, a White House spokesman said.
Dozens living in the region reported falling dishes and violent shaking inside their homes.
"I was alone in the house so I didn't know what to do -- and the first thing when it stopped I ran under the table and tried to get cover because it's the first thing they say to do for an earthquake is get under the table," Diana Martini, who lives in Vallejo, California, told ABC News.
Martini said her television crashed to the ground, along with some of her dishes.
"I'm on the first floor, so that was the scariest thing. I thought the building was going to come down," she said.
Others posted photos and videos of damage inside their homes to social media.
Manisha Galena posted the below video from Alameda, California.
Instagram user @enorym posted the below photo, saying there was no injuries but plenty of things broken at his parents' home.
Tara Sweigart said she felt shaking in Daly City, south of San Francisco.
"I thought someone was wrong with the garage door until I realized that was ridiculous," she told ABC News.
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