BC

Photo: Contributed - USGS

The above map shows the location of the major quake and the aftershocks.

Strong aftershocks continue to hit the area near Haida Gwaii.

The latest reported by the USGS registered at 5.2 on Sunday, October 28, 2012 at 12:16:51 p.m. - Pacific Time, one of four (in red) which struck less than 25 minutes apart.

A 5.5 hit seven minutes earlier preceded by a 5.4 at 12:03 and a 6.3 at 11:54 a.m. 

As well, there was a 5.1 at 9:17, a 4.2 at 7:04, a 4.1 at 6:45, a 4.8 at 6:09, a 4.1 at 5:38, a 4.0 at 5:18, a 4.1 at 5:05 and a 4.8 at 4:27.

A violent earthquake measuring 7.7 jolted British Columbia's north-central coast Saturday night, frightening residents and forcing many to temporarily leave their homes for higher ground ahead of a possible tsunami.

Tsunami warnings were issued for the North Coast, the Haida Gwaii islands, parts of the central BC coast, the coast of Alaska and as far away as Hawaii.

Early Sunday morning the warnings were downgraded to advisory status, meaning evacuations were no longer necessary, and they were cancelled altogether a few hours later.

Residents near the centre of the quake said the violent jolting lasted for up to a minute, but no injuries or major damage had been reported.

Carsten Ginsburg, who lives in the small community of Bella Coola southeast of Prince Rupert, said the quake lasted about 40 seconds.

"It shook everything. The electricity went out, the power lines were swinging all over the place and stuff was falling off the shelves."

Brent Ward, an earth scientist at Simon Fraser University, said the earthquake was the second largest to hit the country since 1949, when another earthquake was recorded in the same area with a magnitude of 8.1.

"It's an earthquake in an area that gets a lot of earthquakes," he said. "It's a tectonically active area."

Ward said the area is known as the Queen Charlotte fault, where the earth's plates slide horizontally across each other in a strike-slip action, similar to what happens along California's San Andreas fault.

"Stresses build up because of that movement, and every so often we get the release of that stress in the form of an earthquake."

Ward said he wasn't surprised the tsunami warning was shortlived because the strike-slip movement along the fault doesn't generally trigger tsunamis.

"To trigger a tsunami you need to have a vertical movement of the sea floor, and it's that vertical movement that displaces water and triggers the tsunami," he said. "Because it's sliding across each other, you're not generally moving the water."

In fact, hours after the earthquake, Dennis Sinnott, who works at the Institute of Ocean Sciences, said the largest wave hit Langara Island, a northern Haida Gwaii island, and measured just 69 centimetres.

The quake also set off emergency sirens across the Pacific on the islands of Hawaii, but even as people were moving to higher ground, the warning was called off.

In Alaska, the wave surge was just 10 centimetres, much smaller than officials had been forecasting.

Kelli Kryzanowski, manager of strategic initiatives Emergency Management BC, said the initial earthquake occurred at 8:04 p.m. inland on Haida Gwaii and was initially recorded at a magnitude of 7.1 but was quickly upgraded to a magnitude of 7.7.

Kryzanowski said small waves generated by the quake, measured at 28 centimetres and 44 centimetres, also hit the northern tip of Vancouver Island.

"What we're seeing at this time are relatively small sea-level fluctuations," she said.

BC Justice Minister Shirley Bond said there appeared to be little damage from the quake.

"We're certainly grateful at this point," said Bond, who spoke to reporters during a late night conference call. "We're very grateful for that, but we'll wait until we can actually see the impact."

After the quake, Ginsburg said he ran home as quickly as he could to see if there was a tsunami warning.

"Which of course there was," he added.

Ginsburg owns the Float House Inn on the public wharf in Bella Coola and had about six customers celebrating a birthday party.

They all evacuated to about 35 metres above sea level.

"I'm assuming that it's OK," he said laughing. "I'm keeping my fingers crossed."

Bella Coola resident Barb Cornish, 60, said she considers herself a very calm person.

"But I found it quite unnerving," she told The Canadian Press.

Cornish lives in a log house and had been told that it's one of the safest places to be in the event of an earthquake.

But she said it sure didn't feel safe Saturday night.

"The log house swayed and creaked and my light over my kitchen table was swaying, some chimes went off. I stood up and I could feel the undulations under my feet, to the point where I almost got nauseated."

--From the Canadian Press

Here is a list of the quakes and their locations:(All times UTC)

• 5.3 206km S of Masset, Canada 2012-10-28 09:17:27 52.159°N 132.149°W 10.2
• 4.2 215km S of Masset, Canada 2012-10-28 09:15:48 52.102°N 131.653°W 10.0
• 4.5 208km SW of Masset, Canada 2012-10-28 08:47:58 52.901°N 134.629°W 10.0
• 4.3 216km S of Masset, Canada 2012-10-28 08:22:04 52.066°N 132.073°W 10.0
• 5.0 198km SSE of Masset, Canada 2012-10-28 07:25:22 52.270°N 131.493°W 10.6
• 4.9 140km S of Masset, Canada 2012-10-28 07:16:37 52.775°N 132.456°W 11.3
• 4.6 212km S of Masset, Canada 2012-10-28 07:12:14 52.109°N 132.221°W 10.0
• 4.4 231km S of Masset, Canada 2012-10-28 07:02:19 51.941°N 131.836°W 10.8
• 5.0 203km SSE of Masset, Canada 2012-10-28 06:16:53 52.268°N 131.212°W 11.5
• 4.5 139km SSW of Masset, Canada 2012-10-28 05:51:17 52.815°N 132.714°W 10.3
• 4.2 181km SSE of Masset, Canada 2012-10-28 05:47:08 52.429°N 131.451°W 10.1
• 4.1 248km S of Masset, Canada 2012-10-28 05:38:38 51.786°N 132.312°W 10.1
• 4.3 211km S of Masset, Canada 2012-10-28 05:21:36 52.139°N 131.571°W 10.0
• 4.3 169km S of Masset, Canada 2012-10-28 05:15:12 52.499°N 132.222°W 10.1
• 4.5 178km S of Masset, Canada 2012-10-28 05:02:49 52.409°N 132.165°W 10.3
• 4.3 180km S of Masset, Canada 2012-10-28 04:54:46 52.403°N 132.439°W 10.1
• 4.7 162km SSW of Masset, Canada 2012-10-28 04:41:05 52.592°N 132.670°W 10.0
• 4.6 140km SSW of Masset, Canada 2012-10-28 04:33:51 52.906°N 133.120°W 10.0
• 5.1 237km SSW of Masset, Canada 2012-10-28 04:25:17 52.019°N 133.370°W 10.1
• 4.8 202km S of Masset, Canada 2012-10-28 03:52:24 52.199°N 131.986°W 10.9
• 7.7 139km S of Masset, Canada 2012-10-28 03:04:10 52.769°N 131.927°W 17.5

Check here for the US Geological site.