Tsunami warning ends for B.C. after large earthquake strikes off Alaska

A tsunami warning for coastal British Columbia and parts of Alaska has endedafter a powerful earthquake struckabout 250 kilometres southeast of Chiniak, Alaska, early today.

• What are tsunamis?
• Why B.C. and Alaska avoided a massive tsunami

The quake struck at 1:31 a.m. PT Tuesday and prompteda tsunami warning for the entire B.C. coast and a tsunami watch for the entire U.S. West Coast.

In Port Alberni,a city that was devastated by a tsunami in 1964, Mayor Mike Ruttan activated the four tsunami sirens at around 3 a.m. PT, alerting 17,000 residents to move to higher ground.

"The warning was repeated every 10 minutes for twominutes [in duration]. They're very loud, there's no way you can ignore them. And then in between time, the paper mill was blowing its horns for extended periods of time to let people know there was civic emergency."

Hear the sound of the sirens below:

Ruttansaid although the city could have communicated better on social media, the evacuation was orderly.

"I am pleased with the response for the most part," he said.

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In Tofino, on the west coast of Vancouver Island, warning sirens were activated on the two main beaches in town,and hundreds of people evacuated to the emergency reception centres at the community hall and an elementary school.

"Everything has proceeded in a really orderly fashion," said TofinoMayor Josie Osborne."This is why we train, this is why we do exercises and this is why spend time making emergency plans and then testing them."

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The provincial emergency systems worked the way it was supposed to, saidB.C.'s public safety minister.

"Whether it was in Esquimalt where we sawfirefighters and first responders going door to door, or... Queen Charlotte City which was fully evacuated,orthe sirens in Tofinoand Ucluelet,and people going to their local emergency centres, people responded admirably and I think the emergency services did a remarkable job," saidMikeFarnworth.

The U.S. Geological Survey initially reported the quake's strength at 8.2early Tuesdayandlater revisedthat to 7.9, with a depth of25 kilometres. At least three aftershocks were reported.

"This is a place in the world where we see historically a lot of large earthquakes," saidCBCseismologist JohannaWagstaffe.

Wagstaffesaid early datashowed themovement of tectonic plates under the ocean was more of a side-to-side motion than what's known as a mega-thrust.

• Fault Lines with Johanna Wagstaffe

"Mega thrusts are the ones we really worry about when it comes to widespread and large tsunamis because there is so much more vertical displacement of the ocean floor," she said.

"Side-to-side can definitely still generate a tsunami, and again we are seeing a small one, but this motion doesn't generateas large of a tsunami as what we would get with a mega-thrust."

Emergency Info BC, directed by the province's lead agency for disaster management, said the warning did not include Vancouver.

Emergency Info BC warned people in the affected area to move away from the water, off beaches, and away from harbours, marinas, breakwaters, bays and inlets. Boat operators were advised to move their boats out to sea to a depth of at least 55 metres.

Trevor Jarvis, the emergency co-ordinator for the Village of Masset on the north end of Haida Gwaii, said he sent out an emergency text to residents and set off the tsunami emergency siren just after 2 a.m. on Tuesday. Everyone on the north end of the village wastold to get to higher ground.

The quake struck280kilometres southeast of Kodiak, Alaska.People reported on social media that itwas felt hundreds of kilometres away in Anchorage. Some said they saw the water retreatingin Kodiak harbour, a possible sign that strong waves could return.

However, Kodiak police later said the tsunami warning was downgraded to advisory. They also said theyreceivedtwo reports that tide levels in the channel werefluctuating "by sixinches to one foot."

The U.S. Pacific Tsunami Warning Centre issueda tsunami watch for the state of Hawaii that was sooncancelled.