Earlier this month 400 tremors, which were not felt, were documented within a 24 hour period, with most of them located just south of Victoria. (Map from John Cassidy/Twitter)

Tiny tremors causing Vancouver Island to move away from B.C. mainland

When the North American plate moves, energy is released and causes a shift to the west

Tiny tremors in recent weeks are causing southern Vancouver Island to shift roughly four to five millimetres away from the Lower Mainland, says a local expert.

According to John Cassidy, an earthquake seismologist with Natural Resources Canada, the shift occurs when the Juan de Fuca plate sinks under the overlying North American plate, which Vancouver Island is on, causing them to lock together and store energy.

When the North American plate moves and releases some pressure in what is known as an episodic tremor and slip process, energy is released in the form of tiny tremors and causes the shift to the west. “As the ocean plate continues to be pushed towards us and it hits North America, it causes a buckling and a squeezing,” Cassidy said. “We have thousands and thousands of these little tiny tremors that nobody feels and they happen at the same time. When we record these tremors that we can easily locate, that’s the same time that Vancouver Island changes direction and moves to the west.”

RELATED: More than 150 tremors hit Vancouver Island in last 24 hours

Roughly 20 years ago, new GPS instruments were deployed and showed seismologists how the surface of the earth was moving.

What researchers found was that south Vancouver Island was slowly moving east roughly one centimetre towards the Lower Mainland each year. But as scientists began to process the data, they found it wasn’t moving smoothly.

Similar to a pin ball machine in which the ball bounces from one side of the machine to the other, scientists found southern Vancouver Island was also doing the same. Every 14 to 16 months over a two to three week period tiny tremors cause southern Vancouver Island to change direction and move roughly four to five millimetres to the west, away from the Lower Mainland, before continuing to move east again.

Cassidy said the information has helped researchers map out the parts of the subduction fault that are locked and where energy is being stored for future earthquakes. It allows them to estimate ground shaking, but doesn’t allow them to predict when an earthquake could take place.

Northern Vancouver Island will also go through a similar process within the next couple of months, changing directions and moving to the west, before continuing to move east.

While Cassidy said the shift is not out of the ordinary, it is a reminder to Island residents that they live in an active earthquake zone.

“We’re just a little bit farther from Vancouver for a few weeks,” he joked, adding the shift has also been seen in other parts of the world as well.

“It’s been scientifically useful, but for all of us, it’s a good reminder that this is an active earthquake zone.”


Like us on Facebook and follow us on Twitter

kendra.wong@goldstreamgazette.com

 

Southern Vancouver Island has shifted four to five millimetres away from the mainland due to a number of recent tiny tremors. (Pixabay stock photo)

Just Posted

UPDATE: 47-year-old man arrested after nine hour police standoff

Prince Rupert RCMP used specialized tactics to apprehend the man wanted for assault with a weapon

PHOTO GALLERY: Malicous Monster Truck Tour

Monster trucks caught in action in Terrace, B.C.

Equality and more jobs in coal terminal’s future

Ridley Terminals Inc. shipments out of Prince Rupert increased by 90 per cent in 2017

Squatters’ campfire leads to emergency response

Prince Rupert fire crews responded to smoke near Roosevelt Elementary School on July 17

CMTN First Nations Fine Arts program offers new advanced diploma

The 10-month program will focus on enhancing jewellery, sculpture and marketing skills

Community garden in Prince Rupert takes shape

Transition Prince Rupert lays foundation for shared edible garden on Overlook

Newspaper carriers wanted!

Contact The Northern View today to find out how you can become a part of our team

‘Amazing Race Canada’ competitors face B.C. challenge

They drove Corvettes, mastered falconry basics, and ate blueberry pie in the Cowichan Valley

Grizzly bear jumps in river, chases B.C. kayaker

The bear got a bit too close for comfort along the Elaho River near Squamish

Evacuation alert issued due to Dog Creek Trail Wildfire

An evacuation alert has been issued by the Regional District of Bulkley-Nechako… Continue reading

Parks Canada looks to shine light on cloudy future for historic sites

A plan is in place to produce 10-year plans designed to turn around sagging attendance figures

B.C. poet shines a bright light on struggle with homelessness

Book launch for John La Greca’s Homeless Memorial is at Vernon’s Gallery Vertigo July 21.

Ontario police say attack on Muslim man was motivated by hate

Two men, aged 27 and 19, have been charged with assault in the incident

Canadian Tire delivers toys to ease kids’ street play pain in B.C. neighbourhood

It’s like Christmas for 11 kids who are supposed to be confined to their yards by strata bylaw

Most Read