A strong earthquake shook Hawaii, jolting residents out of bed and causing a landslide that blocked a major highway.
Hundreds of hotel guests and hospital patients were evacuated, and aftershocks kept the state on edge. Governor Linda Lingle issued a disaster declaration for the entire state, saying there had been damage to buildings and roads.
There were no reports of fatalities, but the state Civil Defense had several reports of minor injuries.
The quake hit at 7:07 am local time (1607 GMT) on Sunday, 10 miles (16 kilometers) north-northwest of Kailua Kona, a town on the west coast of Hawaii Island, also known as the Big Island, said Don Blakeman, a geophysicist at the National Earthquake Information Center, part of the US Geological Survey.
Blakeman said there was no risk of a Pacific-wide tsunami, but there was a possibility of significant wave activity in Hawaii. The Pacific Tsunami Center reported a preliminary magnitude of 6.5, while the US Geological Survey gave a preliminary magnitude of 6.6.
The earthquake was followed by several strong aftershocks, including one measuring a magnitude of 5.8, the Geological Survey said. Experts said aftershocks could continue for weeks.
"We were rocking and rolling," said Anne LaVasseur, who was on the second floor of a two-story, wood-framed house on the east side of the Big Island when the temblor struck. "I was pretty scared. We were swaying back and forth, like King Kong's pushing your house back and forth."
Mayor Harry Kim estimated that as many as 3,000 people were being evacuated from three hotels on the Big Island. Brad Kurokawa, Hawaii County deputy planning director, confirmed the hotels were damaged, but could not say how many people had left.
They were being taken to a gynasium until alternate accomodations could be found, he said. Water pipes exploded at Aston Kona By The Sea, an 86-unit condominium resort, creating a dramatic waterfall down the front of the hotel from the fourth floor, said Kenneth Piper, who runs the front desk.
"We are a concrete building, but we really shook. You could almost see the cars bouncing up and down in the parking garage," he said.
The quake caused widespread power outages, and phone communication was possible, but difficult. By midday Sunday, power was restored to Hilo on the Big Island and was starting to be restored to Maui, said Chuck Anthony, a spokesman for the Hawaii National Guard.
Some Honolulu neighbourhoods also had power late on Sunday afternoon, a spokesman for Hawaiian Electric Co said. Officials did not have a firm estimate of how many people were without power.
Lingle told radio station KSSK that she toured the Kona area by helicopter to view the damage, including earth falling into Kealakekua Bay.
"You could see the water was turning brown," said Lingle. A FEMA computer simulation of the quake estimated that as many as 170 bridges on the Big Island could have suffered damage in the temblor, said Bob Fenton, FEMA director of response for the region. More than 50 federal officials were en route to the Big Island to assess damage and begin recovery work, he said.
On Hawaii Island, there was some damage in Kailua-Kona and a landslide along a major highway, said Gerard Fryer, a geophysicist at the Pacific Tsunami Center. Officials also said there were reports of people trapped in elevators in Oahu.
In Waikiki, one of the state's primary tourism areas, worried visitors began lining up outside convenience stores to purchase food, water and other supplies.
Managers were letting tourists into the darkened stores one at a time.
Kona Community Hospital on the western side of Big Island was evacuated after ceilings collapsed and power was cut off, according to a hospital spokeswoman Terry Lewis. Power was restored later, and the emergency room was accepting patients, hospital officials said.
Airports were functioning despite the power outages, though travel was difficult and some flights were being cancelled, officials said.
The quake hit roughly 150 miles (240 kilometers) southwest of Honolulu's Oahu Island, near a much less populated area. The Big Island has about 167,000 people, according to a 2005 Census estimate, and many of them live in and around Hilo, on the opposite site from where the quake was centered.
Earthquakes in the 6.0 magnitude range are rare in the region, though they have happened before. The region more commonly sees temblors in the 3-and 4-magnitude range caused by volcanic activity.
"We think this is a buildup from many volcanic earthquakes that they've had on the island," Waverly Person, a geophysicist with the US Geological Survey's National Earthquake Information Center said. The last Hawaiian earthquake this strong struck more than 20 years ago. The magnitude 6.7 caused heavy property damage on Hawaii Island and collapsed trails into a volcano in Hawaiian Volcanoes National Park on November 16, 1983.