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Seismologist says ‘The Big One’ would be 200 times worse

A 6.6-magnitude earthquake that shook much of southwestern B.C. should be a reminder that British Columbians live in a very active quake region and should be ready for when “The Big One” hits, according to a prominent seismologist.

John Cassidy with the University of Victoria said hundreds of aftershocks were reported after Wednesday night’s quake, which hit on the Nootka fault zone off the west coast of Vancouver Island. The largest aftershocks had magnitudes of 4.2 and 5.

Aftershocks were felt from one end of Vancouver Island to the other and parts of Metro Vancouver and the Fraser Valley. There were reports that aftershocks were felt as far as Kelowna and Penticton in the province’s Interior.

“We’ve been seeing non-stop aftershocks. We’ve recorded literally hundreds of aftershocks, all very tiny except for the initial two or three,” the expert told CTV Morning Live.
Most of the aftershocks are in the 2-magnitude range, much smaller than the initial shaker that caused buildings and light fixtures to sway across the province.

Cassidy says the shaking from last night’s seismic activity pales in comparison to what will happen if the long predicted “Big One” hits B.C.

“You’d have to take the shaking by about 200 times to get to the realty big one, the magnitude 9 earthquakes, that we know have occurred off of our coast,” he said.

Woefully underprepared

Last month, B.C. Auditor General Russ Jones said the province appears to be woefully underprepared for a major seismic event.

Jones said that the province’s emergency management organization is “not adequately prepared for a catastrophic earthquake.”

His report also found the province and EMBC haven’t made earthquake preparedness a priority since the last audit was released in 1997.

In response, the province said in coming months it will launch an awareness campaign geared toward getting B.C. residents to properly prepare for a seismic event.

B.C. forms part of the North American portion of what is called the Pacific “Ring of Fire,” a 40,000 km horseshoe of ocean trenches and volcanoes where 90 per cent of the world’s earthquakes take place.

According to Natural Resources Canada, the Geological Survey of Canada records more than 1,000 earthquakes in western Canada each year. More than 100 magnitude 5 or greater earthquakes have been recorded in the ocean west of Vancouver Island in the past 70 years.

How to get ready

The City of Vancouver is treating the event as a gentle nudge for people to have an emergency kit for their home or office.

The mayor’s office says people should have an emergency plan in place and also be prepared to survive for several days without food, water or shelter.

The city offers free workshops to learn how to prepare for earthquakes and other emergencies.

Cassidy says the B.C. government is doing a good job seismically readying schools in case of a major event, and all the work done ahead of time will be well worth it.

“When a very large earthquake hits this region, all of the preparedness that we’re doing, all of the work on bridges, the science, the engineering, that will all pay off when the really bigger earthquakes hit in this region because we’ll be better prepared,” Cassidy said.

Two-thirds of Canadians recently polled in a Red Cross survey said they haven’t taken any steps to prepare for a disaster, like an earthquake, flood or tsunami, primarily because they don’t think it’s going to happen – or they simply haven’t thought about it.

The agency rolled out a new disaster preparedness calculator application last year that tests how ready you are for an emergency.

The Facebook app lets users drag and drop the items they already have at home into a theoretical emergency kit. It then calculates how ready you are according to how many adults, children and pets are in your home.

The calculator will then generate a shopping list of items you need to build your own home kit, things like flashlights, batteries, water bottles, candles and waterproof matches. The list can also be downloaded to make shopping easier.

During an earthquake, those inside are advised to drop under any heavy furniture and cover your head to prevent being hit by any falling objects. If you can’t get under something strong, flatten yourself or crouch against an interior wall.

Public Safety Canada says to avoid the following during an earthquake: doorways, windows and tall furniture, elevators and downed power lines. It also advises to stay away from coastlines, in case the earthquake triggers a large ocean wave or tsunami.

Source: http://bc.ctvnews.ca/seismologist-says-the-big-one-would-be-200-times-worse-1.1790585

Earthquake hits off coast of Port Hardy, B.C.

VANCOUVER – A 6.6 magnitude earthquake struck off the coast of Port Hardy on Vancouver Island Wednesday night.

According to the United States Geological Survey, (USGS), it struck at 8:10 p.m. PDT and the epicentre was located about 91 km south, off the coast, at a depth of about 11 km. It was originally recorded as a 6.7 but was downgraded to a 6.6 magnitude quake.

Residents in Port Hardy said the ground shook for about 35 to 40 seconds during the preliminary earthquake. Groceries were knocked off the shelves at the local Overwaitea store.

People are saying they felt it as far away as Langley and Kelowna.

The National Weather Service says there is no risk of a tsunami.

However, the USGS says to expect aftershocks. Earthquakes Canada reports there have been three aftershocks – magnitude 5.0, 4.2 and 4.2 struck the same region at about 8:20, 8:41 p.m. and 10:16 p.m. PDT respectively. These secondary shockwaves are usually less violent than the main quake but can be strong enough to do additional damage to weakened structures and can occur in the first hours, days, weeks, or even months after the earthquake.

Taimi Mulder, a seismologist with Natural Resources Canada, said this area gets hit by a magnitude 6 earthquake every one to two years. “It occurred on the edge of where the Pacific plate touches the North America plate, where it starts to go underneath,” she said. “It’s an area where we do have a history of having earthquakes.”

“It [was] right at the boundary where the off-shore Juan de Fuca Plate starts to subduct or go under the edge of the North America Plate.”

“It’s part of the normal seismicity that we’ve been getting,” she added, “since we’ve been monitoring very closely over the past 20 years, 30 years.”

Pat Quealey from Emergency Management B.C. said everyone reacted as they should have in this situation. He said they are hearing there may be some minor damage, but no significant damage. However, they are checking into reports that a First Nations lodge may have shifted on its foundations during the earthquake.

“In the wider context, we need to be prepared all along the Pacific Rim to respond to seismic threats,” he said. “The really important thing is we can never be too prepared. We need to be prepared all along the Rim of Fire for this risk.”

“It’s a really good reminder to all of us that preparedness starts with local families,” he added. “We live in a volatile area and it’s necessary to be prepared. Through that vigilance and understanding of the risk, we’ll all do well together.”

Mayor of Port Hardy, Bev Parnham, said she was actually at a reception when the earthquake struck.

“We were just in the process of welcoming the lieutenant-governor to the community, and the earth started to shake and the building started to shake,” she said. “It was up there with one of those ones that you do feel and that you do remember.”

However, everyone remained very cool. “I think by the time we realized what had happened we were all just sort of looking at each other and [said] ‘Oh, that was an earthquake,’” said Parnham.

“We’re not hearing of any reports [of damage]. Our own infrastructure has been checked and things are fine. We haven’t heard any reports from any communities in the North Island. So, we’re not expecting to hear that there is any great deal of damage,” she added.

Emergency services in Port Hardy are on alert, but Parnham said they are always prepared as they live in a seismic area.

Simon Fraser University Geologist Brent Ward said in comparison this was quite a large earthquake. “Very lucky that it’s off the coast and it’s not that close to high population centres,” he said. “Because this is actually bigger than one of the earthquakes that hit Christchurch in New Zealand and that caused extensive damage.”

“This was quite shallow.”

Ward said he is not surprised many people across the Lower Mainland could feel the shaking. “In certain situations where people are living on or on top of thick, soft sediments, the earthquake waves actually become stronger so I would expect that people in Richmond, Delta, parts of Langely, where they’re on the thick Fraser River sediments, would feel the earthquake, whereas someone like me, whose on sort of a bedrock area with thin sediments, I didn’t feel anything.”

Global BC anchor Sophie Lui felt the earthquake in downtown Vancouver. “I was sitting on my couch and I heard my vertical blinds shaking,” she said. “And thought at first that maybe the rain had started, but they kept shaking and I looked back and my chandelier or light fixture was shaking as well. And then I realized that the shaking kept going and kept going and I thought ‘ok I think we’re going through this again.’”

She said she did not feel the building shaking too much, but it did last about 20 to 30 seconds.

“Most people around Vancouver who felt it seemed to be up high in high rises,” she said.

Diane Brennan was visiting her daughter in Sayward on Vancouver Island and said “I just felt the room swaying. I started to just feel dizzy and I was wondering what was going on, and I looked up and the room was just undulating.”

Source: http://globalnews.ca/news/1287994/earthquake-hits-off-coast-of-port-hardy-b-c/

B.C. earthquake: 6.6-magnitude quake hits near Port Alice

Some downtown Vancouver highrise residents felt buildings sway

A 6.6-magnitude earthquake struck last night shortly after 8 p.m. PT, with the epicentre located 40 kilometres southwest of Port Alice, according to the Pacific Tsunami Information Centre.

There were no initial reports of damage or injury.

The earthquake was initially reported at 6.7 magnitude, but the U.S. Geological Survey’s National Earthquake Information Centre later changed the scale of the quake to 6.6.

The epicentre had a depth of 11 kilometres, according to USGS. The Pacific Tsunami Information Centre initially reported it to be 22 kilometres.

Although the earthquake was powerful enough to generate a local tsunami, the risk of one was quickly ruled out.

‘The windows started rattling’

People from as far away as Kelowna, B.C., about 575 kilometres from the epicentre, reported feeling buildings sway. Within an hour of the quake, more than 400 people also reported feeling it to the USGS.

Some residents in highrises said they felt their building sway, including Marjorie Blair, who was in her 12th-storey apartment in Burnaby when it hit.

“I looked up and my first instinct is always to look at the chandelier when something happens, and it is rocking I am telling you,” said Blair.

“Then I heard the clicks, the clicks on the glass, and there are the rods on the curtains and they were hitting the glass.”

In Port Hardy, about 89 kilometres northeast of the earthquake’s epicentre, Deputy Fire Chief Brent Borg said there happened to be a meeting at the fire hall when the earthquake struck.

“The windows started rattling, the walls started rattling and one of the lieutenants says, ‘Did we just have an earthquake?'” he told CBC News.

Borg said one of the local firefighters phoned in to say he had some pictures rattle off his mantle. He said no local warnings were issued, and firefighters did not have to respond to any emergencies.

“It was a pretty minor shake. It was less than 10 seconds.”

Port Hardy Mayor Bev Parnham told The Canadian Press that although the quake was short, it was strong.

Pamela Shea was working a late shift at Port Hardy’s Airport Inn when she felt the quake, which she said lasted between 10 and 12 seconds.

“My chair was rolling back and forth, the bottles were rattling,” she told CP. “I’ve lived here 37 years and I’ve never felt anything like it.”

The earthquake was followed by three aftershocks, one of magnitude 5 and the next two both at magnitude 4.2. The second was initially reported at a magnitude 4.

The USGS says aftershocks of this size are normal for a quake of this magnitude.

Earthquakes are common off the province’s coast, where the Juan de Fuca tectonic plate meets the Pacific tectonic plate. However, few earthquakes are large enough to be felt by humans.

The most recent large earthquake in B.C. was in October 2012. A magnitude 7.7 quake shook the northern B.C. Haida Gwaii Islands.

Source: http://www.cbc.ca/news/canada/british-columbia/b-c-earthquake-6-6-magnitude-quake-hits-near-port-alice-1.2620109

After the Chile quake, is ‘the big one’ around the corner for B.C.?

Around 8:45 p.m. Wednesday, residents on Chile’s coast were jolted from where they stood or sat when the earth began to shake violently. Items tumbled off shelves, landslides were triggered, power was knocked out to thousands, and several fires destroyed businesses. Though tragic, it was miraculous that only six people lost their lives in the magnitude-8.2 quake.

A similar situation — or worse — could lie in store for residents along the coast of British Columbia, though seismologists aren’t concerned about the Chilean earthquake being the catalyst to a major earthquake here at home.

“We don’t expect any impacts in B.C. in terms of triggering [an] earthquake,” John Cassidy, a seismologist with Earthquakes Canada told Global News. “Looking back at previous events over time, we don’t see any direct link between these very distant earthquakes triggering very large, very distant earthquakes.”

However, that doesn’t rule out smaller ones being triggered.

Cassidy explained that when large earthquakes — magnitude 8 or 9 — occur any place on Earth, it can trigger smaller earthquakes around the globe.

“The [seismic] waves from that earthquake will circle the globe,” he said. “And as those waves, sort of a rolling motion, pass through certain areas, they will trigger small earthquakes. So you’ll see micro-seismic, or very tiny earthquakes, that people don’t feel.”

Generally, the this type of repercussion is limited to volcanic areas, which also includes Yellowstone National Park. That area received a magnitude-4.8 earthquake on March 30. It was the strongest in the area since 1980.

“It’s an interesting phenomena that was discovered, but we don’t see these waves triggering large earthquakes,” Cassidy said. “But it’s a young science and we can’t say absolutely not, but our experience so far is that we’re not seeing large earthquakes being triggered by these waves.”

The Chilean earthquake is actually similar to the type of earthquakes B.C. receives, called subduction earthquakes. This occurs when a part of one tectonic plate slides beneath another.

“It’s a very important earthquake, in that we can learn from this earthquake, because we have exactly the same kind of earthquakes off of our coast.”

The plate that subducted, or moved beneath another plate, off the coast of Chile is called the Nazca Plate. The plate moves toward Chile about 6 cm a year. Off the coast of B.C., the Juan de Fuca plate moves in the same manner at 5 cm a year.

In the case of the Juan de Fuca plate, seismologists know that a large earthquake occurs roughly between 200 to 850 years apart. And by ‘big one,’ seismologists mean a magnitude-9. The last one was in 1700, which means that, statistically, B.C. could expect one.

“We’re right in that window, where certainly we should be prepared for one of those earthquakes.”
If such a major earthquake were to occur, the effects could be enormous. For one, the shaking would last for about four to five minutes. For those on the west coast of Vancouver Island, they would have less than an hour to make it to higher land before a major tsunami washed ashore. As well, parts of the west coast of the island could drop as much as a metre.

“You’d see damage. You’d see landslides and liquifaction effects through the lower mainland and certainly all across Vancouver Island,” Cassidy said.

Not only that, but places as far as Toronto could feel the shaking. People in highrises would feel their buildings sway as the shockwave reached the city.

Trying to predict earthquakes

The difficulty with earthquakes is that there is, for now, no way to predict them. Though “swarms” of quakes — a cluster of localized earthquakes — have been linked to predicting a bigger earthquake, it’s not an exact science.

“It’s something that certainly people will be looking at really carefully now, because that’s one of the big questions,” Cassidy said. “Before one these giant earthquakes, is there any indication, any signal, any change in land level, or in seismicity that might tell us that one of these giant earthquakes is about to occur?”

But looking back at earthquake history, these swarms predict a larger one only 1 out of 20 times. That means 19 out of 20, there is no major quake that follows, making it an imperfect way to forecast larger earthquakes.

The good news for B.C. residents is that the Chile earthquake isn’t a portent of disaster. But the big one could be around the corner.

Source: http://globalnews.ca/news/1246076/after-the-chile-earthquake-is-the-big-one-around-the-corner-for-b-c/