Seismologists record more than 3,500 ‘tiny tremors’ on Vancouver Island in nine days

Seismologists record more than 3,500 ‘tiny tremors’ on Vancouver Island in nine days

Natural Resources Canada seismologist John Cassidy, otherwise known as Earthquake Guy, says these are not earthquakes but rather a good reminder that we live in an active subduction zone.

Seismologists have recorded more than 3,500 tiny tremors on Vancouver Island, but don’t panic, these aren’t earthquakes. That’s the last thing B.C. needs in 2020.

Natural Resources Canada seismologist John Cassidy, otherwise known online as the Earthquake Guy, posted a tweet early Thursday about the event. He says while these tremors don’t provide answers to when a major earthquake will hit, they “certainly remind us that we live in an active subduction zone.”

The cluster of tiny tremors is likely an ETS event, an episodic tremor and slip, said Cassidy. ETS is a process that occurs deep below the Earth’s surface along faults that form the boundaries of tectonic plates. It involves repeated episodes of slow fault slip of a few centimetres over a period of several weeks, accompanied by seismic tremors.

ETS events can help scientists better understand the quake hazard by studying how it affects the subduction fault beneath the Island, which is about 30 kilometres beneath the surface, and in Vancouver, at 60-to-70 km beneath the surface.

“This is helping us to map out where the subduction fault is completely locked and storing energy,” he said. “These look very different from earthquakes but we can get a better understanding of the process … There are still a lot of questions.”

During ETS events there is also a “slip,” where the region moves to the west over the course of a few weeks.

“This is quite remarkable when you think about Vancouver Island moving a few millimetres,” he said. “But it’s not clear whether this will impact that subduction fault.”

ETS events are a regular occurrence on the Island, and happen about every 14-to-15 months. The last ETS event on southern Vancouver Island was one year ago, said Cassidy.

“These tiny tremors that we locate … have a very different appearance on our seismographs (than quakes). Energy builds up slowly and drops off slowly. They are not felt but can be detected and located by our very sensitive seismographs,” he said. “It’s the slip that we are really watching for.”

The Cascadia Subduction Zone, which runs from northern Vancouver Island to Northern California, is Canada’s most active earthquake region.

As for a major quake, Cassidy says scientists still can’t say when this will happen or how large the next one will be, but huge strides have been made in understanding temblors and how often they strike an area. Unlike 20 years ago, seismologists now know that B.C. has seen magnitude-nine earthquakes and that they occur roughly every 500 years or sometimes as short as 200 years between quakes.

“We know the last one struck on Jan. 26 of the year 1700. So we know the exact date and time,” said Cassidy.

Source: https://vancouversun.com/news/seismologists-record-more-than-3500-tiny-tremors-on-vancouver-island-in-nine-days

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New study detects thousands of earthquakes in B.C. Peace region, most linked to fracking

New study detects thousands of earthquakes in B.C. Peace region, most linked to fracking

B.C.’s Peace region is experiencing roughly 1,500 small earthquakes a year and most of them are connected to fracking operations, according to a new study.

Researchers set up 15 earthquake detectors around the region and recorded 5,757 tiny earthquakes that were otherwise undetected between 2017 and 2019.

“The vast majority of them seem to be connected with hydraulic fracking operations,” said Alessandro Verdecchia, one of the study’s lead researchers, during an interview on CBC’s Daybreak North. The research was published in the Seismological Research Letters journal in July.

According to the McGill University geophysicist, the connection was made by pinpointing the precise time and location of seismic events and comparing that data to information from fracking companies about their operations.

“If we see some kind of connection in time and place between the operation and the occurrence of the earthquake we can associate an occurrence of the earthquake with the fracking operation.”

Detecting large magnitude quakes

Verdecchia says the researchers are trying to determine the largest magnitude earthquake that can be created by fracking in the western Canada sedimentary basin, a region in northeast British Columbia that includes the Montney Formation, a shale gas area that’s home to nearly 3,000 production wells.

“Large magnitude events can produce larger acceleration and velocity of the ground and, of course, can produce larger damages to infrastructure,” he said.

In 2018, a 4.5 magnitude earthquake shook Fort St. John. No damage was reported, but people could feel it as far as Dawson Creek and Chetwynd.

Verdecchia says the largest magnitude detected in the western Canada sedimentary basin that’s been associated with fracking was a 4.6 event in August 2015. However, in China, there has been a magnitude 5.5 seismic event that’s been connected with a hydraulic fracking operation.

The other thing researchers want to understand is how far from the fracking these events can occur.

“This will be helpful for operators when they decide to start a fracking well, to begin operations, because they can more or less keep a distance let’s say from important infrastructures or populated areas,” Verdecchia explained.

According to the research so far, seismic events have been detected at a distance as far as five kilometres from the fracking operations.

Source: https://www.cbc.ca/news/canada/british-columbia/new-study-detects-thousands-of-earthquakes-in-b-c-peace-region-most-linked-to-fracking-1.5668236

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4.5-magnitude earthquake strikes off Vancouver Island, reported felt in Vancouver

4.5-magnitude earthquake strikes off Vancouver Island, reported felt in Vancouver

An earthquake that struck off the coast of southern Vancouver Island Friday afternoon was reportedly felt in downtown Vancouver.

Earthquakes Canada said the 4.5-magnitude quake struck 36 kilometres southwest of Bamfield just after 1:30 p.m.

The United States Geological Survey (USGS) initially recorded the quake at a 4.8 magnitude, but later lowered it to a 4.5.

Both agencies said no tsunami is expected, and no reports of damage have been received.

Nearly 300 people have reported feeling shaking to the USGS. Another 200 people on Vancouver Island also reported feeling the quake, with most putting it at a Level 2 intensity.

However, some people in downtown Vancouver said they felt shaking, including workers in Robson Square and on Main Street.

Residents of other parts of Metro Vancouver, including Richmond and Burnaby, also said they felt slight shaking.

Friday’s quake comes days after a 4.8-magnitude earthquake struck further north off the island coast. Nine others struck in the same area west of Port Hardy around Christmas Day.

Source: https://globalnews.ca/news/6459690/earthquake-vancouver-island-felt/

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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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