UPDATE - Oct. 28, 2012: A 6.4-magnitude earthquake was reported near Sandspit, B.C. Sunday at 11:54 local time. It has not resulted in a tsunami warning.
A magnitude 7.7 earthquake struck B.C.'s coastal Haida Gwaii area Saturday night, triggering tsunami warnings along the north coast and as far away as Hawaii.
The quake was centered 202 kilometres south-southwest of Prince Rupert at a depth of 17.5 kilometres, said the U.S. Geological Survey. It struck at 8:04 p.m. PT, followed by several aftershocks, as powerful as 5.8.
Jennifer Bailey, who lives in Port Clements, a village in Haida Gwaii, was walking down the stairs when the initial quake hit. She said she could hardly stand up and thought her two-storey house was coming down. The shaking broke glasses in her home and briefly took out the power, she said on Twitter.
Natural Resources Canada said the first earthquake was felt across much of north-central B.C., including Haida Gwaii, Prince Rupert, Quesnel, and Houston.
"It looks like the damage and the risk is at a very low level, we are very grateful for that," said Shirley Bond, B.C.'s minister responsible for emergency management, in a conference call with media on Saturday night. She said four communities had been evacuated.
"A small tsunami has been recorded by a deep ocean pressure sensor," said Emergency Management B.C.
Late Saturday night, tsunami warnings were downgraded to advisories for the north coast of B.C. and Haida Gwaii. Warnings remained for Hawaii. (UPDATE: The warning for Hawaii has been cancelled and replaced with an advisory.)
"A tsunami is a series of waves and the first wave is not usually the largest and could last several hours," warned Emergency Info B.C.
The warning -- which means that widespread dangerous coastal flooding with powerful currents is possible -- requires people to move inland or to higher ground immediately, while an advisory for potentially strong currents urges people to stay away from beaches and shorelines.
A tsunami wave of up to 1.7 metres was estimated for Sunday at 4:52 a.m. in Pacofi Bay in the Haida Gwaii region, reports the Global Disaster Alert and Coordination System. It stated about "2,000 people are within 100 kilometres" of that prediction.
Waves recorded by B.C. tidal stations were relatively minor, with the highest wave of 69 centimetres (2.3 feet) coming in at Langara Island. Dennis Sinnot from the Insititute of Ocean Science told reporters: "Right now things seem to be settling down at all of our sites."
Terminals at the Prince Rupert port were shut down as a precaution.
The earthquake comes less than two weeks after a province-wide earthquake drill.
SFU geology professor Brent Ward said that the quakes reported off in Haida Gwaii were not related to "The Big One" that's been long predicted to hit B.C.'s West Coast.
"It's kind of a different type of fault up there. It's more like the San Andreas Fault. It's sliding past each other, whereas The Big One is where the Juan de Fuca plate is trying to go underneath North America," Ward told The Huffington Post B.C.
He said the predicted earthquake, expected to shake Vancouver, may reach a 9.2 magnitude, similar to the 2011 earthquake that triggered a major tsunami in Japan.