6.0-Magnitude Earthquake Hits Northern California

A strong 6.0-magnitude earthquake hit northern California on Sunday, seriously injuring three people and igniting fires in the Napa valley wine region, according to reports.

The US Geological Survey said that the quake was the most powerful to hit the San Francisco Bay area since the 1989 6.9-magnitude Loma Prieta earthquake.

The quake struck at 3:20 am. PDT about 10 miles northwest of American Canyon, which is about 6 miles southwest of Napa. No deaths were reported but Napa city officials said 208 people were treated at the city's Queen of the Valley Hospital and three people suffered serious injuries.

Among them was a 13-year-old kid who was critically injured by a fallen fireplace and had been flown to a hospital for neurological care.

According to the US Geological Survey, earthquakes happen when two blocks of the earth suddenly slip past one another at a point called the fault line.

California's governor Edmund Brown declared a national state of emergency Sunday, saying in a statement that "the circumstances of the earthquake, by reason of their magnitude, are or are likely to be beyond the control of the services, personnel, equipment and facilities of any single local government."

In addition to damage from collapsed buildings, Napa city officials said that there have been reports of gas leaks, water main leaks and power outages in about 20,000 homes.

Aftershocks were expected to continue for several weeks, though State Geologist John Parrish told The Associated Press that they would decrease in magnitude and it was unlikely that there would be a large follow-up earthquake. Still, he warns that people should be weary because buildings that were damaged by the quake are now more susceptible to collapse from aftershocks.

"Anytime we have an earthquake, whether it's magnitude 6.0 or smaller, they serve as a good reminder that we do live in earthquake country and need to be prepared," USGS spokeswoman Susan Garcia told the Agence France-Presse (AFP).