A powerful earthquake rocked north-west America, shattering windows, showering bricks on to footpaths and sending terrified crowds running into the streets in cities including Seattle in Washington State and Portland in Oregon.
Despite the 6.8-magnitude quake, damage and injuries from the tremor were relatively minor.
Experts attributed this to the quake's depth.
About 250 people were reported injured in Seattle and the state capitol Olympia, officials said, with at least three in a serious condition.
The earthquake temporarily shut down Seattle airport, cut power to hundreds of thousands of people, cracked the dome atop the Capitol in Olympia and briefly trapped about 30 people on top of the swaying landmark Space Needle, 605 feet above the city.
The quake hit at 10.54 a.m.(6.54 p.m GMT) and was centred 35 miles south-west of Seattle, according to the National Earthquake Information Centre in Golden in Colorado. It was the strongest to hit Washington state in 52 years.
Experts said its depth - in a fault about 33 miles underground - spared the north-west catastrophic damage.
Officials said millions of dollars spent to prepare buildings and highways to protect against earthquakes had paid off.
Damage could run into the billions but that was considered light in a highly developed area with more than three million residents.
President George W. Bush asked the director of the Federal Emergency Management Agency, Mr Joe Allbaugh, to travel to Seattle to offer help.
"Our prayers are with those who were injured and their families and with the many thousands of people whose lives have been disrupted," Mr Bush said.
Screams erupted at a Seattle hotel where Microsoft founder Bill Gates was addressing an education and technology conference.
He was whisked away as his audience bolted for the exits. Some people were knocked down by others trying to get out as pieces of the ceiling fell.
AFP