How fracking is linked to Fox Creek earthquakes
WATCH ABOVE: A 4.4 earthquake rocked the Town of Fox Creek Saturday. As Lisa Wolansky tells us, the oil and gas town has felt its share of shaking.
TORONTO – The trembling that shook residents in Fox Creek, Alberta, on June 13 wasn’t the first. And there’s a chance it won’t be the last.
Since Nov. 2013, Natural Resources Canada has recorded 24 earthquakes in the region of magnitude 3 or greater and 81 of magnitude 2 or greater. The June 13 earthquake is the second since January that was magnitude 4 or greater.
A mere days before the magnitude 4 trembler shocked people of Fox Creek, a study was published in the July issue of the Seismological Research Letters about the link between fracking and earthquakes in the area while dispelling some myths.
“It’s a myth to consider that hydraulic fracturing is responsible for all induced earthquakes, or even all injection-induced earthquakes,” said David Eaton, professor of Geophysics at the University of Calgary. Eaton was also a guest co-editor of the July publication. “In the United States, the vast majority seem to be associated with wastewater disposal.”
In order to liberate gases trapped in rock, oil and gas companies inject water, sand and some chemicals into the ground through high pressure. The pressure increases fractures in the rock and the gas emerges and is piped out. That pressure could indeed cause an earthquake.
However, disposal of wastewater — be it left over from the fracking process or as a result of oil extraction — can also cause induced earthquakes.
Unlike in the United States, earthquakes have indeed been linked to fracturing in Canada, the Fox Creek earthquakes in particular.
Ultimately, it’s our need for energy that is responsible for the induced earthquakes.
“In either case, withdrawing or injecting fluids into the subsurface there’s a known linkage for the potential of induced seismicity.”
But this isn’t something new. In fact, Eaton said that researchers and gas and oil companies have known for decades that there is a link between fracturing (and wastewater injection) and earthquakes.
Hydraulic fracturing can cause hundreds if not more of tremors. But they’re magnitudes of less than zero.
A representative from the Alberta Energy Regulator (AER) confirmed that, since the Fox Creek event, production has temporarily stopped. Operations will not be able to resume until the AER approves.
Any time a magnitude 2 or greater earthquake occurs within five kilometres from a well, the operator is required to contact the Alberta Energy Regulator. Anything over magnitude 4 and the operator is required to cease operations and inform the AER.
Eaton said that though there has been far more public attention devoted to induced earthquakes, there is the need to look at the rate of induced earthquakes compared to the number of wells. There are 30,000 fracking wells in western Canada, while fewer than one per cent of them cause earthquakes.
But what is needed is a better understanding of the faults that lie beneath these wells.
“I think it’s very important for the people in Fox Creek to be made aware of the evolving understanding of the seismic activity in that area,” Eaton said. “That really requires transparency in the part of regulator and transparency in the part of the industry. I think individuals there have the right to express concern.”
But Eaton said that, though there have been links to fracturing and earthquakes since the 1950s, it’s only recently that there seems to be a “heightened perception” of the issue of induced earthquakes, likely due to social media and the media in general.
Eaton and his colleagues have dispatched a team to the field to install portable equipment in order to further research aftershocks following the event. This may help geophysicists obtain better information on the fault that likely lies beneath the well.
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