The vast majority of large earthquakes that rocked British Columbia and Alberta last year were caused by the oil and gas sector, and especially hydraulic fracking, according to a new report.
The comprehensive study — published in the peer-reviewed journal Seismological Research Letters — looked at 12,389 fracking wells and 1,236 wastewater wells along the B.C.-Alberta border.
The good news is only a small fraction of them — 39 fracking wells and 17 wastewater wells — caused any caused seismic activity.
But the few that did were responsible for 90 per cent of seismic events over magnitude 3.0 to hit the region during the last five years. Fracking wells, specifically, were deemed responsible for 60 per cent.
While there's been no damage or injuries connected to these human-triggered quakes, lead author Gail Atkinson worries it's only a matter of time.
"Only a small fraction of hydraulic fracture wells induce significant earthquakes, but there are so many drilled every year, that this significantly changes seismic hazard in the region, and poses risks to critical infrastructure in the immediate vicinity of such operations," Atkinson, a professor at the University of Western Ontario's Department of Earth Sciences and an expert in seismic hazards, told VICE News.
"These risks need to be more carefully considered and regulated to avoid damage."
There have been close calls. In January, a hydraulic fracking well near Fox Creek, Alberta, was shut down indefinitely after a 4.6-magnitude quake struck the area. Nobody was hurt, but residents felt the ground shake.
Still, a spokesman for B.C.'s Oil and Gas Commission expressed confidence in the provincial safety mechanisms, which include enhanced monitoring and an order to shut down all industry operations shut down if seismic activity reaches a certain threshold.
"The Commission has effective regulatory measures that apply to every well approved in northeast B.C. to ensure there is no risk to the safety of the public," Graham Currie said.
The reason those measures exist, he noted, is because study's findings aren't groundbreaking. Numerous studies have linked the fracking industry to earthquakes.
Last summer, a fracking operation sparked a 4.8-magnitude earthquake 10 kilometres northwest of Fort St. John, B.C, in what may be the largest earthquake in the world caused by hydraulic fracturing.
This is not the first study to link earthquakes to fracking, which has caused an energy boom in North America over the last decade despite backlash from environmentalists and some First Nations. But these findings mark one of the most comprehensive looks at Western Canada's liquified gas industry.
What's more, the study nails down the definitive link between the quakes and the actual process of hydraulic fracking, which involves injecting water and chemicals deep into the ground to break open rocks and release oil and natural gas.
That's different from how fracking affects seismic activity in the U.S., where most earthquakes have been linked to the underground disposal of fracking waste materials.
To get a better idea about how to balance the environmental risks with the economic benefits of fracking, the researcher say they need to determine why fracking has different effects in Western Canada than it does south of the border, and why only certain wells seem to trigger quakes.
In the meantime, the B.C. Green Party has reiterated its call moratorium on fracking in the province, which is hedging its financial future on the liquified natural gas industry.
"I am calling on both the government and the official opposition to join me in supporting a moratorium on horizontal fracking in British Columbia," party leader Andrew Weaver said in a statement.
"Other jurisdictions, like Quebec, New York, New Brunswick and Nova Scotia, have already suspended the practice and B.C. should follow suit."
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