Earthquakes in Canada: The impact of climate change on seismic activity
“An earthquake fault that is primed and ready to go is like a coiled spring … all that is needed to set it off is – quite literally – the pressure of a handshake,” scientist Bill McGuire, author of Waking the Giant: How a changing climate triggers earthquakes, tsunamis, and volcanoes, wrote in the Guardian last fall.
A warmer world prompting heavy masses of ice to melt, and heavier rains to fall, could trigger that activity, the theory goes.
“The heavy rain induces thousands of landslides and severe erosion, which removes ground material from the Earth’s surface, releasing the stress load and encouraging movement along faults,” said Shimon Wdowinski, lead researcher of a 2011 study that found earthquakes tend to follow tropical cyclones.
While many parts of the country are prone to seismic activity, experts say Canadians shouldn’t worry about their city or town suddenly becoming a earthquake hot spot due to a warmer atmosphere.
Thousands of earthquakes annually
Earthquakes rattle Canada thousands of times every year — there are an estimated 2,500 annually in Western Canada alone. Thanks to the Internet, social media and apps, we’re now more aware of the activity that has always commonly occurred.
“A lot of people think there’s suddenly an increase but it’s just that they’re getting a lot more coverage than they used to,” said Alison Bird, earthquake seismologist with the Geological Survey of Canada.
Climate change, “won’t generally cause more earthquakes to happen,” Bird said.
“No, climate change will not result in increased earthquake activity,” agreed Gail Atkinson, professor of earth sciences at Western University, in an email to Global News.
However, in the North adjustments to the changing landscape has prompted some seismic activity, Bird said.
“The glaciers receded from the last ice age, which was considerable time ago — we’re talking about thousands of years,” said Bird. “Because the weight of those glaciers receding has been lifted, the ground is slowly moving up after having that weight removed from it, and you can have earthquakes because of that sort of thing. They tend to be quite small.”
While there may be more small events, Canada’s sparsely-populated Arctic is unlikely to suddenly see massive seismic activity.
“Climate change is not something that just started,” noted Christie Rowe, assistant professor in earth and planetary sciences at McGill University.
“All the earthquake patterns that we know of are basically [from] the last century. So the patterns that we know of are already happening in the climate changing world.”
Drop, cover and hold on
Because of a subduction zone along the coast, British Columbia is prone to “the largest earthquakes in the world, the mega-stress earthquakes with tsunami,” said Bird.
Those massive earthquakes, often called “the big one”, happen every few hundred years. The last one to strike along the B.C. coast was on Jan. 26, 1700.
Earthquakes on the smaller scale — 4.5 or 5 in magnitude — can cause some damage, particularly in areas where infrastructure was not designed with quakes in mind. The “big one” would be a 9.
While Canada is seldom struck by catastrophic earthquakes, experts agree Canadians from coast to coast should be prepared.
“You can argue that it’s very unlikely that someone in Saskatchewan is going to experience a damaging earthquake in their lifetime, but it’s not just for where they live, but where they play,” said Bird.
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Bird encourages drill exercises in all provinces and territories — drop, cover and hold on.
“When you’re in a stressful situation your brain doesn’t function properly, and your instinct is to run. Running is one of the worst things you can do in an earthquake.”
Earthquakes are pretty much impossible to predict, Simon Fraser University earth sciences department chair Brent Ward told Global News last month.
“All we can do is prepare. People should have a plan, because they’re not going to be able to use their cellphones. Have a plan about where to meet and what to do in this situation, and have an earthquake kit,” Ward said.
Many parts of Canada are prone to seismic activity.
According to the Geological Survey of Canada and Natural Resources Canada, there is a 30 per cent chance that B.C. will see an earthquake strong enough to cause significant damage in the next 50 years.
Ground shake, landslides, tsunami and fire would ensue.
The region spanning from the St. Lawrence River in Quebec to the Ottawa Valley — which includes Quebec City, Montreal and Ottawa — has a five to 15 per cent chance of a major earthquake over the next half century.
With a file from Jill Slattery
© 2017 Global News, a division of Corus Entertainment Inc.