An earthquake measuring 6.5 on the Richter scale has killed two people and shaken California from San Francisco to Los Angeles.
The earthquake struck yesterday morning, hitting hardest in the town of Paso Robles. Up to 45 people in the region were injured.
Two women were crushed in the downpour of rubble when the roof of the landmark 19th-century clock tower building collapsed in Paso Robles, officials said.
First reports said three people were killed but officials said the two women, both believed to be employees of a dress shop in the building, were the only fatalities. More than 45 others in the region were injured, some with broken bones and lacerations.
Beyond this San Luis Obispo County town, about 185 miles north of Los Angeles and 30 miles from the epicentre, damage from the quake was "modest," officials said.
Power was cut to some 75,000 homes and businesses and the quake shook the historic Hearst Castle, a major California tourist attraction but caused no damage there or at a nuclear power plant in the area.
The US Geological Survey said the quake would produce hundreds of aftershocks over the next days, weeks and even years but there was only a 5 to 10 per cent risk that any of the aftershocks would be bigger than the initial quake.