A powerful earthquake of 7.9 magnitude struck off the coast of Alaska early Tuesday, prompting tsunami warnings or watches as far away as California.
The quake struck at 0931 GMT in the Gulf of Alaska, 280 kilometres (175 miles) southeast of the town of Kodiak, the US Geological Survey said, revising a preliminary estimate of 8.2 magnitude.
The epicentre was 10 kilometres under the seabed.
Tsunami warnings were issued for south and southeast Alaska and the west coast of Canada, the National Tsunami Warning Centre said.
Less-ominous tsunami watches were issued for the US west coast – the entire coasts of California and Oregon and part of Washington State and Hawaii out in the Pacific.
Tsunami waves could hit the coasts of Oregon and Washington as early as around 1310 GMT, the Portland office of the National Weather Service said.
Heather Rand, who was 360 miles away in Anchorage, told CNN it felt like the longest earthquake she had ever experienced.
“It was a very long, slow build up. Creepy, more than anything. Definitely the longest and I was born here,” Rand said, adding the only damage was cracks in the wall.
So far no quake damage or large waves have been reported in Kodiak, which is on an island off the coast, police spokesman Tim Putney told AFP.
“We are half an hour beyond the time we were told the first wave might hit. Nothing has happened,” he said around 1115 GMT.
“We have people with their eyes on the sea, from a safe distance,” Putney added.
Still, authorities urged coast dwellers to seek safety.
“If you are located in this coastal area, move inland to higher ground,” the Anchorage Office of Emergency Management said.
“Tsunami warnings mean that a tsunami with significant inundation is possible or is already occurring. Tsunamis are a series of waves dangerous many hours after initial arrival time. The first wave may not be the largest.”