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

Greyhound’s departure opens door for BC Bus

After years of service cuts and declining service quality, Greyhound’s corporate owners… Continue reading

Update: Park pipeline protesters say arrest is a ‘declaration of war’

Led by Kanahus Manuel, the Tiny House Warriors moved into park in Clearwater last week

Police investigating more racist slogans on First Nations signs

Police are investigating racist graffiti being posted on First Nations signs in the Kamloops area

Update: Kamloops wildfire now mapped at 500 hectares

Firefighters worked overnight on what was a fast-growing wildfire east of Kamloops.

France doubles up Croatia 4-2 to win World Cup

Played in Moscow Russia, latest Fifa World Cup marks the highest scoring final since 1966

BC Games: Dance, spoken-word highlights at Opening Ceremony in Cowichan

Hundreds of athletes and thousands of volunteers, coaches, parents and officials

B.C. city wants pot punted from farmland

Concerned about conversion from growing food to making marijuana

World’s translators push back on forcing Trump interpreter to testify

Democrats had asked translator to testify about Trump’s lengthy conversation with Putin in Helsinki

No decision on B.C. school stabbing suspect’s mental fitness for trial

The BC Review Board could not determine whether Gabriel Klein, 21, is fit to stand trial

Canadian government threatens to retaliate if Trump imposes auto tariffs

U.S president had suggested that auto imports pose a national security risk to the U.S.

Wildfire evacuation order forces bride to search for new wedding venue

Fitzpatrick Family Vineyards is under an order due to the Mount Eneas wildfire south of Peachland

Recent online kitten abuse video raises serious social media questions

UBC and UFV profs weigh in on the subject of online sharing, shaming, and our digital landscape

UPDATED: ICBC fights back against claims that it’s ‘ripping off’ B.C. RV drivers

Canadian Taxpayers Federation is urging the provincial government to open up ICBC to competition

Summerland issues State of Local Emergency in response to wildfire

Two homes under evacuation order; evacuation alert remains in place as result of wildfire

Most Read