California begins clear-up after San Francisco Bay quake

Workers are assessing damage and have begun to clear up after a 6.0 magnitude quake in California's San Francisco Bay area, the strongest there in 25 years.

No-one has been killed but scores of people sought medical care after Sunday's quake, which struck four miles from the town of American Canyon.

The quake started fires, cracked roads, caused gas and water leaks and left dozens of buildings uninhabitable.

Governor Jerry Brown declared a state of emergency in the affected area.

President Barack Obama has also been briefed on the earthquake.

'It was burning'

The city of Napa was one of the worst affected areas, where fire-fighters tackled some six blazes, as well as dozens of burst water mains and gas pipes.

On Monday, officials said an initial assessment found dozens of buildings made unsafe by the earthquake, including a Napa County courthouse where a 10ft (3m) wide hole showed the offices inside.

Napa was one of the worst-affected areas

A full assessment of the cost has yet to be released

The Queen of the Valley Medical Center in Napa reported treating 172 people, although many were for minor injuries.

One adult is still in critical condition, while a 13-year-old boy is in serious condition after being hit by debris from a fireplace.

Several residences in a mobile home park were destroyed by a fire caused by the quake.

"There were some explosions, and it was burning. Everybody was out in the street. I didn't get anything out of the house," Nola Rawlins, a resident of a mobile home park told the Associated Press (AP).

The quake came as many of the region's vineyards were preparing to harvest their crop. The shaking broke thousands of wine bottles and toppled barrels.

Richard Ward of Saintsbury Winery told AP he lost at least 300 bottles and his grape harvest would be pushed back several days.

City public works director Jack LaRochelle said the immediate concern in Napa was the water main system.

He said teams were working in 12-hour shifts to restore water, but that the roads were not seriously damaged and bridges were "in pretty good shape".

A car seat is retrieved after a car port collapsed on a vehicle in Napa

The quake came right before many wineries' grape harvest

A skateboarder finds a use for the buckled pavement

The US Geological Survey (USGS) warned that aftershocks of up to 5.0 magnitude were likely in the coming week.

It said Sunday's quake struck at 03:20 local time (10:20 GMT) at a depth of 6.7 miles.

The epicentre was 51 miles from Sacramento and about 30 miles north-east of San Francisco.

California lies on the San Andreas Fault, which forms the tectonic boundary between the Pacific Plate and the North American Plate, two of the large moving plates that form the Earth's crust.

In 1989, a 6.9 magnitude earthquake struck south of San Francisco, killing more than 60 people, many when part of motorway in Oakland collapsed, and injuring hundreds.