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Officials began inspecting bridges and roads across Hawaii early Monday following the strongest earthquake to rattle the islands in more than two decades, a 6.7-magnitude quake that caused blackouts and landslides but no reported fatalities.

At least one stretch of road leading to a bridge near the earthquake's epicenter on the Big Island collapsed, Civil Defense Agency spokesman Dave Curtis said Monday.

Several other roads on the Big Island were closed by mudslides, debris and boulders, but most were still passable, he said. The power were back on across most of the islands Monday morning. About a dozen schools were closed for inspection, but no major injuries or deaths had been reported.

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"If you're going to have an earthquake, you couldn't have had it at a better time — early in the morning when people aren't even out of their homes yet," Curtis said.

"I think people, under the circumstances, have remained very calm," he said.

The quake hit at 7:07 a.m. Sunday, 10 miles north-northwest of Kailua-Kona, on the west coast of Hawaii Island, known as the Big Island, said Don Blakeman of the National Earthquake Information Center, part of the U.S. Geological Survey. The USGS on Monday raised the magnitude for the quake from a preliminary 6.6 to 6.7.

A government computer simulation estimated as many as 170 bridges could have been damaged by the quake, said Bob Fenton, Federal Emergency Management Agency director of response for the region.

Gov. Linda Lingle, who was in a hotel near the epicenter, issued a disaster declaration for the state, and the state Civil Defense had several reports of minor injuries as aftershocks continued to shake the island chain.

"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."

The shaking broke water pipes at ResortQuest Kona By The Sea, turning the front of the building into a dramatic waterfall starting at the fourth floor, said Kenneth Piper, who runs the front desk.

"You could almost see the cars bouncing up and down in the parking garage," Piper said.

The earthquake was followed by several strong aftershocks on Sunday, including one measuring a magnitude of 5.8, the USGS said. Forecasters said there was no danger of a tsunami, though choppier-than-normal waves were predicted. The quake struck during heavy rain, though, adding a risk of mudslides.

Earthquakes in the 6.0 magnitude range are rare in the region, which 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," said Waverly Person, a geophysicist with the USGS.

Monday morning, the Honolulu airport was filled with passengers still waiting for a flight out. Silas Garrett, a 52-year-old truck driver from Memphis, had been there since 8 a.m. the previous morning. He said he and his five sisters slept on the floor using beach towels as blankets and handbags as pillows.

"Every pound we gained on the cruise ship, we lost in the airport," Garrett said. "The quake shook it off."

On the Big Island, Kona Community Hospital was evacuated after large chunks of its ceilings collapsed and power was cut off. At least 10 patients were evacuated to a medical center in Hilo, and 30 others were moved to a nearby conference center, said hospital spokeswoman Terry Lewis

"We were very lucky that no one got hurt," Lewis said.

County of Hawaii Mayor Harry Kim estimated that as many as 3,000 people were evacuated from three hotels on the Big Island. Brad Kurokawa, Hawaii County deputy planning director, confirmed the hotels were damaged and said people were taken to a gymnasium until other accommodations could be found.

The power outages were largely due to power plants turning off automatically when built-in seismic monitors were triggered by the quake. All electricity systems needed to be rebooted, which was expected to take several hours in more populated areas. Most of the region had electricity again Monday.

"We were totally prepared for a disaster such as this, but obviously with a disaster this big you can't be prepared for everything," Rodney Haraga, director of the Hawaii Department of Transportation, told ABC's "Good Morning America" Monday.

Hawaii's largest quake on record was an 1868 magnitude-7.9 earthquake that triggered a tsunami and spawned numerous landslides that resulted in 31 deaths, according to the USGS. The last major temblor was in 1983, a magnitude 6.7.

In Waikiki on Oahu, worried visitors began lining up outside convenience stores for food, water and other supplies Sunday. Managers were letting them into the darkened stores one at a time.

Karie and Bryan Croes waited an hour to buy bottles of water, chips and bread.

"It's quite a honeymoon story," said Karie Croes, as they sat poolside, surrounded by grocery bags, at ResortQuest Waikiki Beach Hotel.

The Big Island has about 167,000 residents, many of them in and around Hilo, on the opposite site of the island from the quake's epicenter.