Fracking triggers 90% of large quakes in B.C., Alberta oil and gas patch
But less than 1% of fracking activity directly responsible for earthquakes
There's bad news and good news when it comes to fracking and earthquakes in Western Canada, according to new research from a paper co-authored by a Geological Survey of Canada scientist.
The new research confirms a definitive link between hydraulic fracturing and almost every large induced earthquake recorded in B.C. and Alberta's oil and gas patches since 1985.
In other words, scientists now have evidence that 90 per cent of seismic events over magnitude 3.0 that shook the region were triggered by crews fracking for oil and gas underground.
But with so many fracking wells in operation, the evidence also shows only a tiny fraction of them — less than one percent — directly triggered earthquakes.
Now, scientists say, they need to determine what factors caused 39 wells to trigger quakes.
They say it appears other factors they don't yet fully understand must also be at play determining which fracking operations trigger earthquakes and which do not.
"It is important for us to realize that indeed hydraulic fracturing can induce earthquakes," said Honn Kao, a research scientist with the Geological Survey of Canada and one of 13 co-authors of a study, set to be published in the May-June issue of the peer-reviewed Seismological Research Letters, the journal of the Seismological Society of America.
Earthquakes are definitely part of the fracking risk...- Scientist Honn Kao
"But the evidence so far indicates there are other factors that may be important in this process as well, so that we cannot blame all the hydraulic fracturing operations for inducing big earthquakes," he said.
Kao said these other factors are likely related to local geology, local hydrology and the distribution of tectonic plates and fault lines, but more research is needed.
In British Columbia, where the government has pinned its financial future on ramping up fracking so it can export gas as liquified natural gas, these research results will be closely analysed.
'Part of the risk'
"We realize induced earthquakes are definitely part of the risk that may be associated with the development of the oil and gas," said Kao. " That is a cause for so much concern from the regulators as well as the public."
"It's important to conduct more research to figure out the best balance between the protection of the public safety and the environment and the economic benefits of developing unconventional oil and gas.
"We will provide the necessary science and all the scientific analysis to the policy making process so collectively B.C. and Alberta will make the wise decision if they want to proceed [with fracking] or not," said Kao.
12,289 fracked wells studied
Kao and his fellow scientists based their research on 25 years of data on earthquake activity in a swathe of northeastern B.C.and western Alberta, called the Western Canada Sedimentary Basin, that's not traditionally seismically active. They combed through data between 1985 and 2015 about seismic events larger than magnitude 3.0, as well as information from 12,289 hydraulically fractured gas and oil wells, and 1,000 fracturing waste disposal wells.
The results? More than 90 per cent of large earthquakes were associated with nearby fracking operations. More than 60 per cent of these quakes were linked to hydraulic fracture with about 30 to 35 per cent coming from disposal wells. Only five to 10 per cent of the earthquakes had a natural tectonic origin.
As well, just 0.3 per cent of the fracked wells triggered large earthquakes. And those large earthquakes didn't result in any injuries or significant damage.
It's really just a matter of time before we start seeing damage...- Lead study author Gail Atkinson
While the percentages sound small, lead author Gail Atkinson of the University of Western Ontario said that thousands of hydraulic fracturing wells had been drilled every year in the region, increasing the likelihood of earthquake activity.
"We haven't had a large earthquake near vulnerable infrastructure yet," she said, "but I think it's really just a matter of time before we start seeing damage coming out of this."
Atkinson said the new numbers could be used to recalculate the seismic hazard for the region, which could impact everything from building codes to safety assessments of critical infrastructure such as dams and bridges.
"Everything has been designed and assessed in terms of earthquake hazard in the past, considering the natural hazard," she said. "And now we've fundamentally changed that, and so, our seismic hazard picture has changed."
Different from U.S. frack 'quakes
The research also confirmed differences scientists have long suspected between Canada and the United States. In the U.S., induced earthquakes are most often linked to the underground disposal of fracking waste materials, rather than the fracturing process itself.
Hydraulic fracturing or "fracking" is a process that involves pumping a mixture of water, sand and chemicals underground at high pressure to fracture rock and release trapped natural gas.