At about 3:20 a.m., a 6.0 earthquake hit north of San Francisco in Napa County. The earthquake was 10 miles northwest of American Canyon, about 6 miles southwest of Napa. The AP reports that the United States Geological Survey said "it was the largest tremor to shake the Bay Area since the magnitude-6.9 Loma Prieta quake in 1989." 87 injuries have been reported via Queen of the Valley Medical Center in Napa, including at least one child who was critically injured by falling debris, as the Chronicle reports. Two adults are also reported as having critical injuries, but thankfully there has been no loss of life. Update: The injury count has risen to 120 as of Monday, with six people listed as critical, as the Marin Independent Journal reports.

Most San Franciscans and East Bay residents felt or were awoken by the sizable quake, which shook houses and knocked things off shelves and walls throughout the city, though little damage has been reported. CalTrain is delaying service and Amtrak's Capitol Corridor service has been suspended for today's 49ers pre-season game at Levi's Stadium as track inspections occur, but CalTrain says it will be running trains to the stadium, as Bay City News reports. ACE special service between Stockton and San Jose has been canceled.

All bridges and major roads are reportedly safe and secure.

There were more than a dozen aftershocks, as KQED reports, including a 3.6 one at 5:47 a.m, and geologists say more could be on the way. Napa city officials report about 30 significant water main breaks and around 100 reports of gas leaks, which PG&E is responding to.

According to NBC Bay Area, it "caus[ed] houses to shake in the center of San Francisco and knock[ed] out power to more than 50,000 houses." However, in Napa:

From SFGate:

Erica Gregory, who was brewing coffee while working by herself at the 24-hour Shell gas station on Highway 29 in Vallejo, said things started to fly off the shelves when the quake hit.

"It was nerve-wracking," Gregory said. "You just have to stand there and take it."

In Benicia, several miles from the epicenter, the quake was strong enough to knock pictures off mantles.

Darryl Sismil, owner of Marin Computer Service in Santa Rosa, described the tremor as "just a rolling sensation. It felt like I was on a boat in the bay."

A cashier at the Napa Valley Casino added, "It wasn't like the shaking I felt in '89. It felt like more of a rolling."

NBC Bay Area chief metereologist Jeff Rainieri said, "The most important thing for people to remember is drop, cover and hold if we do happen to get another big one. If you smell gas it probably means there is a gas leak."

Update: A 10-foot deep crack in the ground was photographed at one Napa vineyard. And as Inside Scoop reports, many restaurants in the area, including those in Yountville, will be closed today as the cleanup begins.

ABC 7 reports a large crack snaking across Highway 121 near Highway 129 where buckling was about 18 inches in places. CalTrans is on the scene trying to repair it. Governor Brown has declared a state of emergency.