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

Snowfall warning: 5-10 cm expected in Lower Mainland

The snowfall will start Tuesday and carry on into the evening, before tapering off Wednesday

Snowfall warning issued for Surrey, Langley

Environment Canada warns to ‘be on the lookout for adverse weather conditions and take necessary safety precautions’

Lost a ring? This White Rock man will find it for you

Chris Turner founded The Ring Finders, an international directory of metal detector hobbyists

PHOTOS: Family Day celebrated at Historic Stewart Farm

Youngsters participate in some old fashioned fun

Clayton’s little neighbourhood libraries are open for business

’Take a book, leave a book’ initiative aims to bring Clayton residents closer together

Mermen calendar targets ‘toxic masculinity,’ raises big money for charities

Newfoundland and Labrador Beard and Moustache Club gave a cheque for more than $202,000 to Violence Prevention NL

Payless to close 248 Canadian stores, saying it’s ‘ill-equipped’ for market

The company will begin closing stores at the end of March

Make sure measles shots up to date, Public Health Agency says

Measles causes high fever, coughing, sneezing and a widespread painful rash

Super snow moon set to rise across B.C.

It is the biggest and brightest moon of the year

‘Our entire municipality is heartbroken’: Seven children die in Halifax house fire

A man and woman remained in hospital Tuesday afternoon, the man with life-threatening injuries

5 to start your day

IHIT investing South Surrey homicide, B.C.’s budget set to focus on climate change, poverty and more

Minister says plans to fight poverty, climate change, focus of B.C. budget

The NDP said in its throne speech last week that affordability will be the hallmark of its initiatives

UPDATED: ‘Violent’ B.C. man back in custody after Alberta arrest

Prince George man with ties to Vernon was being sought by police

After a week away, SNC-Lavalin questions await MPs returning to Parliament

Two have resigned already: Jody Wilson-Raybould was veterans affairs minister and Gerald Butts was Trudeau’s principal secretary

Most Read