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4.7 magnitude earthquake rattles Haida Gwaii

4.7 magnitude earthquake rattles Haida Gwaii

An earthquake rattled the west coast of Haida Gwaii in British Columbia on Saturday.

Earthquakes Canada says the quake with a magnitude of 4.7 struck about 50 kilometres south of the Village of Queen Charlotte.  The national earthquake agency says the tremor occurred just before 11 a.m.

Earthquakes of that magnitude are often felt but typically only cause minor damage, if any.

There were no immediate reports of damage or a tsunami risk.

There have been a number of small earthquakes in Haida Gwaii over the past month but none were higher than a magnitude 2.8.

Source: https://www.cbc.ca/news/canada/british-columbia/haida-gwaii-string-of-earthquakes-1.5354680

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Map shows which areas of Vancouver face most damage in an earthquake

Map shows which areas of Vancouver face most damage in an earthquake

Chinatown, Kitsilano, South Granville and West End would be hardest hit, map shows.

A map released by the City of Vancouver highlights areas that would see the most severe damage during a significant earthquake.

The map was produced as part of the city’s ongoing investments to assess earthquake risk and upgrade infrastructure.

It shows a magnitude 7.3 earthquake would cause the most damage to Vancouver’s older, multi-family residential and commercial areas.

Chinatown, Kitsilano, South Granville and the West End would be hit the hardest, with pockets of damage also highlighted in the Point Grey, Strathcona, Mount Pleasant and Marpole areas.

The map also shows that much of the southern half of Vancouver would see limited damage, although a statement from the city said disruption from such a powerful shake would be felt city-wide.

City officials released the map in preparation for the 2019 Great British Columbia ShakeOut drill, held Thursday morning.

“During an earthquake, the best thing you can do is drop, cover, and hold on,” read a city statement.

The drill is designed to encourage all British Columbians to practise their response to an earthquake and assess emergency preparedness.

Vancouver Fire Chief Darrell Reid said beyond participating in the drill, everyone should be prepared.

“Know the risks, make a plan and have the emergency supplies you need to get by so first responders can prioritize life-saving calls,” said Reid.

The area of greatest risk in B.C. is along the Cascadia subduction zone, a fault running from northern Vancouver Island to northern California that separates the North American tectonic plate and the Juan de Fuca plate west of Vancouver Island.

Earthquake analysts say the Juan de Fuca plate is skidding below the North American plate, creating the potential for a major slip along the fault line, which would trigger a powerful earthquake.

The B.C. government’s earthquake and tsunami guide says quakes powerful enough to cause structural damage happen in the province on an average of once per decade.

The province said there have been four large quakes in the area since a devastating magnitude 9.0 temblor in 1700, including a 7.8 earthquake that caused significant damage across Haida Gwaii in 2012.

Source: https://www.cbc.ca/news/canada/british-columbia/vancouver-earthquake-damage-map-1.5324104

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Strong earthquake hits near volcanic Alaskan islands

Strong earthquake hits near volcanic Alaskan islands

A strong earthquake shook volcanic islands between Alaska and Russia yesterday in the northern part of the Pacific Ring of Fire.

A 6.5-magnitude earthquake occurred at 12:35 p.m. local time (1:35 p.m. B.C. time) on April 2, according to the U.S. Geological Survey.

The epicenter was located in the Rat Island of the Aleutian Islands at a depth of 19 kilometres (12 miles) and 93 kilometres (58 miles) northwest of Amchitka, Alaska.

A tsunami was not expected from the quake, according to the U.S. Tsunami Warning System.

Source: https://www.straight.com/news/1222971/strong-earthquake-hits-near-volcanic-alaskan-islands

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2.2 magnitude earthquake ‘lightly felt’ in Salmon Arm

2.2 magnitude earthquake ‘lightly felt’ in Salmon Arm

A 2.2 magnitude earthquake was felt by some residents of Salmon Arm, B.C. on Saturday night.

According to Earthquakes Canada, the quake was “lightly felt” around 8:40 p.m. There were no reports of damage.

Many residents said they felt their houses shake, and heard something that sounded like an explosion.

Source: https://www.cbc.ca/news/canada/british-columbia/earthquake-salmon-arm-1.5040985

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Fracking connection probed in 4.6-magnitude earthquake near Sylvan Lake

Fracking connection probed in 4.6-magnitude earthquake near Sylvan Lake

The Alberta Energy Regulator is working to determine if a fracking operation caused an earthquake near Sylvan Lake and Red Deer on Monday.

Natural Resources Canada said a 4.6-magnitude earthquake rocked parts of central Alberta just before 6 a.m. The federal department’s website said the tremor was classified as a light earthquake.

The AER has confirmed Vesta Energy had been fracking in the area just prior to the quake, which was detected by the company’s private seismic monitoring devices around 12 kilometres south of Sylvan Lake at a magnitude of 4.16.

The AER said the earthquake was reported to them by the company at 6:20 a.m.

“We are currently reviewing the events to determine if the incident is due to hydraulic fracturing activities or natural causes,” said Natalie Brodych, spokeswoman with the AER.

The regulator said Vesta has stopped work at the site while the AER investigates whether fracking led to the quake.

Earthquakes Canada initially had trouble pinpointing the earthquake, locating it first northeast of Red Deer, then south of the city. The most recent update has placed it 19 kilometres west of Red Deer, near Sylvan Lake. The earthquake occurred about a kilometre below the surface.

There were no immediate reports of damage, but power was knocked out for about 4,600 FortisAlberta customers. A spokesperson said the disruption lasted for a little more than an hour.

AltaLink said a transformer at a substation south of Sylvan Lake tripped around the same time of the quake. The transmission company is still investigating exactly what caused the outage.

The U.S. Geological Survey website says an earthquake similar to the one that struck Alberta has a sensation like a heavy truck striking a building; it can rattle windows and may break some dishes or windows.

Debbi McGillicky, who lives in the Mountain View area of Red Deer, said she and her husband were jarred awake by the quake.

“My husband and I were awakened at 5:55 a.m. when our bed began to shake violently. My husband shot up out of bed and exclaimed, ‘What the hell was that?’,” she told Postmedia. At the time, she thought the quake was some sort of explosion.

Linda Borsato lives in Sylvan Lake and said she was eating breakfast when the earthquake hit.

“There was a pop and the power went out, and right after the power went out the whole house shook from one end to the other,” she said.

“It was pretty freaky to say the least. We didn’t really know what to do when it first happened. . . It was enormous.”

Earthquakes are rare for the Red Deer area; the last recorded quake was in 2016. There was a 4.0-magnitude quake on March 31, 1997.

However, Joanne Gaudet, communications officer for the town of Sylvan Lake, said there has been seismic activity in the past between Sylvan Lake and Rocky Mountain House to the west.

Source: https://calgaryherald.com/news/local-news/red-deer-hit-with-earthquake-monday-morning

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Developing Story: Seismic swarm in progress between Cascadia and San Andreas Faults

Developing Story: Seismic swarm in progress between Cascadia and San Andreas Faults

Four Magnitude-3.4 and larger quakes have struck in two hours, all south of Cape Mendocino, and west of the town of Petrolia, California. Based on the earthquake locations and their focal mechanisms (both by the USGS), the swarm appears to be occurring on a right-lateral reverse fault that connects the northernmost San Andreas-Mendocino Fracture Zone with the shallow portion of the Cascadia Megathrust (as shown by the black half- arrows in the map).

This area has highest quake rate in all of California (http://temblor.net/earthquake-insights/m6-5-earthquake-stresses-offshore-san-andreas-fault-aka-mendocino-fault-zone-1917/). That’s because the two fastest-slipping faults in the western U.S. join, or nearly join, here. It’s also because the bend in both the San Andreas and Cascadia Faults mean that the crust here is being crushed, distorted, and fractured. This distortion cannot be accommodated solely along the great faults, and so there is a plethora of small faults like this one that distribute the stress.

What this event means for the Cascadia and San Andreas Faults is unknown, but it is certainly a swarm to watch.

Source: http://temblor.net/earthquake-insights/developing-story-seismic-swarm-in-progress-in-cascadia-8323/

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3.8 magnitude earthquake hits area northwest of Hampton, NB

3.8 magnitude earthquake hits area northwest of Hampton, NB

Earthquakes Canada has confirmed a 3.8 magnitude earthquake hit an area 17 kilometres northwest of Hampton in southern New Brunswick this morning.

Nick Ackerley, an Earthquakes Canada seismologist, said the earthquake happened at 9:49 a.m. AT, approximately 17 kilometres west-northwest of Hampton and 35 kilometres north of Saint John.

Its preliminary magnitude was reported as 3.7, but Earthquakes Canada upgraded it later Thursday.

It was an “intraplate earthquake,” a type that happened inside the tectonic plate, as opposed to an interplate earthquake, which occurs in areas at the edge of a tectonic plate.

“The causes include things like long-dormant faults from previous mountain-building episodes, and glacial rebound,” Ackerley said.

“This part of Canada was under glaciers until about 10,000 years ago, and when the weight of the ice was lifted off, the Earth is slowly springing back, and that causes stress in the crust of the Earth.”

The government of New Brunswick tweeted officials are aware and are monitoring the earthquake.

Earthquakes Canada has confirmed a 3.8 magnitude earthquake hit an area 17 kilometres northwest of Hampton in southern New Brunswick this morning.

Nick Ackerley, an Earthquakes Canada seismologist, said the earthquake happened at 9:49 a.m. AT, approximately 17 kilometres west-northwest of Hampton and 35 kilometres north of Saint John.

Its preliminary magnitude was reported as 3.7, but Earthquakes Canada upgraded it later Thursday.

It was an “intraplate earthquake,” a type that happened inside the tectonic plate, as opposed to an interplate earthquake, which occurs in areas at the edge of a tectonic plate.

“The causes include things like long-dormant faults from previous mountain-building episodes, and glacial rebound,” Ackerley said.

“This part of Canada was under glaciers until about 10,000 years ago, and when the weight of the ice was lifted off, the Earth is slowly springing back, and that causes stress in the crust of the Earth.”

The government of New Brunswick tweeted officials are aware and are monitoring the earthquake.

Hughes said there’s no visible damage to her home.

Lee Jacobs said she and her husband heard a low rumbling that lasted for several seconds before the house starting “shaking violently.”

“I said, ‘What is that?’ And as soon as I said those words, the house started shaking. You could hear the sound before the shaking started.”

She called the earthquake an “unnerving” experience

3.8-magnitude quake considered minor

A 3.8 magnitude quake “could be widely felt,” according to Ackerley, depending on the depth at which it occurred.

That being said, a 3.8 magnitude is still considered to be a minor earthquake and unlikely to cause damage.

Earthquakes, while rarely severe, aren’t unheard of in New Brunswick.

In the spring of 2018, Earthquakes Canada recorded a “swarm” of 22 minor quakes on the western edge of the province near McAdam, a village also also rattled by a 3.3 magnitude earthquake in 2016.

In November 2016, a magnitude 3.1 earthquake was recorded 23 kilometres west-northwest of Miramichi.

But the last major earthquake, a magnitude 5, hit the Miramichi area in the 1980s, the largest earthquake to have affected the Maritimes since 1929.

Source: https://www.cbc.ca/news/canada/new-brunswick/earthquake-hits-northwest-of-hampton-1.4972818

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A low-intensity hum near Vancouver Island may help predict the next killer earthquake

A low-intensity hum near Vancouver Island may help predict the next killer earthquake

There has not been a major earthquake in the Cascadia subduction zone since 1700. But every year or so, there is a month-long ‘slow slip’ of tectonic plates.

It is well known that, off the coast of Vancouver Island, the massive undersea Juan de Fuca tectonic plate is slowly sliding under the larger North American plate, putting the west coast of Canada at grave risk of a megathrust earthquake and resulting tsunami.

What is lesser known about this process is the massive amount of energy that is unaccounted for, and might be building silently toward catastrophe. Newly published research based on artificial intelligence claims to have found it in a constant, low, background tremor, and, with it, a new way of predicting when the next big one might hit.

There has not been a major earthquake in what is known as the Cascadia subduction zone since about 9 p.m. on Jan. 26, 1700, long before Europeans first landed on Vancouver Island. The event is moderately well known to historians, however, for two reasons.

One is the oral histories and archeological remains of the various First Nations whose villages were swamped by a tsunami. Storytellers began to speak of dwarfs in the mountains who danced around a drum, causing the earth to shake and waters to rise. Others described a sea battle between a thunderbird and a whale that caused “a shaking, jumping up and trembling of the earth beneath, and a rolling up of the great waters,” according to research by Alan McMillan, who studies the archeology and ethnography of Vancouver Island First Nations at Simon Fraser University.

The other reason is that the tsunami also went the other way, westward to Japan, making landfall the next day, killing hundreds and sinking boats.

Ever since, Cascadia has been relatively quiet. But every year or so, there is a roughly month-long “slow slip,” when the North American plate lurches southwesterly over the Juan de Fuca plate.

This slip can account for as much as half of the total relative motion of the tectonic plates, as measured by displacement on the surface. It is usually accompanied by bursts of tremors, but the physics of “slow slip” is not well understood. It only occurs in some regions of the fault line between the plates, for example, while others appear to be “locked,” and only move in megathrust events.

This slip has been observed in advance of major earthquakes, which suggests it might be part of the process that causes them, according to a new paper by Bertrand Rouet-Leduc and Claudia Hulbert of the Los Alamos National Laboratory in New Mexico.

There is also a strange discrepancy between the amount of surface movement as measured by global positioning systems and the amount of energy measured by seismographs in tremors.

Somewhere in this process, a vast amount of energy has gone missing.

The key to finding it was to apply the tools of supervised machine learning, a kind of artificial intelligence that can separate a real signal from background noise. In a newly published paper, the researchers claim to have found that the Cascadia subduction zone is “continuously broadcasting a low-amplitude, tremor-like signal,” and that this low amplitude hum from the depths of the Earth “may account for most of this missing energy.”

Recognizing what this hum reveals about fault line physics might lead to something like an early warning system that “may prove useful in determining if and how a slow slip may couple to or evolve into a major earthquake,” the authors write in the journal Nature Geoscience.

They used seismic data from the Canadian National Seismograph Network and global positioning data from stations in the Western Canada Deformation Array, processed by the United States Geological Survey.

They found the Juan de Fuca plate is moving under the North American plate at around four centimetres a year as the North American plate slips over it. The highest slip speed for the North America plate, moving in the other direction, was also around four centimetres a year, which means that the transition zone between the plates — coastal British Columbia, basically — was slipping at around eight centimetres a year.

“The continuous tremor-like signal we identify tracks the slow slip rate, apparently at all times, and so provides real-time access to the physical state of the slowly slipping portion of the megathrust,” the authors write. “As the slow earthquakes transfer stress to the adjacent locked region where megaquakes originate, careful monitoring of this tremor-like signal may provide new information on the locked zone, with the potential to improve earthquake hazard assessment in Cascadia.”

Source: https://nationalpost.com/news/canada/a-strange-low-intensity-hum-near-vancouver-island-may-help-predict-when-the-next-killer-earthquake-will-strike

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Ontario town rattled by ‘mining-related’ earthquake

Ontario town rattled by ‘mining-related’ earthquake

It wasn’t a particularly strong quake, but it didn’t need to be for Kirkland Lake residents to feel the tremor on Wednesday night [December 12th, 2018] — it happened right underneath their feet.

According to Earthquakes Canada, the magnitude 3.2 earthquake was centred almost directly under the city, 2 km west-southwest of town, at a depth of 1.5 km. More than 100 people reported to Natural Resources Canada that they felt the quake, which struck at 11:16 EST Wednesday night. Weather Network viewers reported hearing a “loud blast that shook a lot of homes” at the time the quake was recorded.

Earthquakes Canada lists the tremor as ‘mining-related’, although no confirmation has been released. Local resident Jeff Wilkinson told CTV News he was concerned it might have been a fracture related to mining. “As you may know,” Wilkinson told CTV, “we have had some fatal rockbursts in this area, so we’re all sort of wondering whether it has happened again.” A rock burst is a sudden, sometimes explosive, fracture that can happen in deep mines. The rock surrounding a mine shaft is under tremendous pressure from the rock surrounding it; sometimes this pressure can cause the rock surrounding the shaft to give way.

DOES MINING CAUSE EARTHQUAKES, OR IS IT THE OTHER WAY AROUND? 

There has definitely been a lot of coverage of fracking-related earthquakes in recent years, as geologists point to the oil-extraction process for the rising number of quakes in places like Ohio and Oklahoma. Earthquakes related to mineral mining are a slightly different animal, however.

As happens with rock bursts, since mining leaves empty spaces that change the balance of pressure on the surrounding rocks, it’s not unusually to get minor earthquakes related to the collapse of excavated regions. The excavation process itself can also result in events that register on the seismometer. According to a report from the Canadian Hazards Information Service, “Literally hundreds of [mining-induced activity] blasts are recorded and identified by the project on a yearly basis.”

Sometimes it’s a case of ‘the chicken and the egg’, however.

A lot of the minerals that people mine for are actually largely found along fault lines — gold being among them. As Daniel Jaska, of the Geoscience Australia Earthquake Alert Centre, put it talking to ABC, “we have mining because of earthquakes.”

“[Minerals like gold] are [along faults] because when and earthquake occurs, there is generally a flow of water or liquid that interacts with the rocks,” said Jaska, “and over many millions of years forms minerals.”

While seismic activity in central Canada tends to be fairly low, thanks to a lake of tectonic plate interactions in the area, there are ‘weak zones’ within plates that are subject to shifting when stress builds up in the interior of a plate, thanks to constant pushing at its edges.

Source: https://www.theweathernetwork.com/news/articles/earthquake-felt-in-kirkland-lake-officials-believe-mining-related-gold-mine-mining-seismicity-rockburst/119806

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Powerful quakes buckle Alaska roads, briefly trigger tsunami warning

Powerful quakes buckle Alaska roads, briefly trigger tsunami warning

Back-to-back earthquakes measuring 7.0 and 5.8 rocked buildings and shattered roads Friday morning, November 30, 2018 in Anchorage, Alaska, sending people running into the streets and briefly triggering a warning to residents in Kodiak to flee to higher ground for fear of a tsunami.

The warning was lifted a short time later. There were no immediate reports of any deaths or serious injuries.

The U.S. Geological Survey said the first and more powerful quake was centred about 12 kilometres north of Anchorage, Alaska’s largest city, with a population of about 300,000. People ran from their offices or took cover under desks.

Cracks could be seen in a two-story downtown Anchorage building, and photographs posted to social media showed fractured roads and collapsed ceiling tiles at an Anchorage high school. One image showed a car stranded on an island of pavement, surrounded by cavernous cracks where the earthquake split the road.

Cereal boxes and packages of batteries littered the floor of a grocery store, and picture frames and mirrors were knocked from living room walls.

People went back inside after the first earthquake struck, but the 5.8 aftershock about five minutes later sent them running back into the streets.

A tsunami warning was issued for the southern Alaska coastal areas of Cook’s Inlet and part of the Kenai peninsula. Kodiak police on Kodiak Island warned people in the city of 6,100 to “evacuate to higher ground immediately.”

The National Weather Service Seattle tweeted a tsunami warning is in effect for Cook Inlet, but it is not expected to affect Washington or B.C.

Anchorage lawyer Hank Graper was driving when the quake struck. He first thought his vehicle had a flat tire, then thought it was exploding. He realized it was an earthquake after he saw traffic poles swaying.

Graper called it the most violent earthquake he’s experience in his 20 years in Anchorage.

David Harper was getting some coffee at a store when the low rumble began and intensified into something that sounded “like the building was just going to fall apart.” Harper ran to the exit with other patrons.

“The main thought that was going through my head as I was trying to get out the door was, ‘I want this to stop,”‘ he said.

Harper said the quake was “significant enough that the people who were outside were actively hugging each other. You could tell that it was a bad one.”

Thrown from bathtub

In Kenai, north of Anchorage, Brandon Slaton was alone at home and soaking in the bathtub when the earthquake struck. Slaton, who weighs 209 pounds, said it created a powerful back-and-forth sloshing in the bath, and before he knew it, he was thrown out of the tub by the waves.

His 55-kilogram mastiff panicked and tried to run down the stairs, but the house was swaying back and forth so much that she was thrown off her feet and into a wall and tumbled to the base of the stairs.

“It was anarchy. There’s no pictures left on the walls, there’s no power, there’s no fish tank left. Everything that’s not tied down is broke,” Slaton said.

Slaton ran into his son’s room after the shaking stopped and found his fish tank shattered and the fish on the closet floor, gasping for breath.

He grabbed the Betta fish and put it in another bowl. He says the area was eerily quiet. His children’s school was evacuated.

Alaska averages 40,000 earthquakes per year, with more large quakes than the other 49 states combined. Southern Alaska has a high risk of earthquakes due to tectonic plates sliding past each other under the region.

According to the U.S. Geological Survey, the Pacific plate is sliding northwestward and plunges beneath the North American plate in southern Alaska, the Alaska Peninsula and the Aleutian Islands.

On March 27, 1964, Alaska was hit by a magnitude 9.2 earthquake, the strongest recorded in U.S. history, centred about 120 kilometres east of Anchorage. The quake and the tsunami it triggered claimed about 130 lives.

Source: https://www.cbc.ca/news/canada/north/earthquake-anchorage-1.4927624

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