Two earthquakes in central Alberta in 2018 and 2019 were caused by nearby shale oil fracturing operations, a research team from the province’s geological society and energy regulator has concluded.
“Investigators determined that nearby fracking operations triggered both earthquakes and also induced other ‘small clusters’ of seismic events in the area with tremors up to a magnitude of 2.0,” CBC reports. Both tremblors hit near Red Deer, Alberta, and one of them took out the power grid in Sylvan Lake, about 24 kilometres away.
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“Recent events were large enough to be felt by nearby residents in Red Deer, who were between four to 10 kilometres away,” the report stated. “The observation of these events in a typically seismically quiescent region was suspicious, considering the recent development of the Duvernay East Shale Basin.”
The quakes hit 3.13 on the Richter scale in 2018 and a “significantly stronger” 4.18 in 2019, CBC says. “At the time, the regulator ordered Vesta Energy Ltd. to suspend hydraulic fracturing operations at the site in order to protect the public and the environment,” the national broadcaster writes. It also ordered the Calgary-based company to report on recent earthquake activity in the area, provide fracking data for the specific well site, and explain how it would eliminate or reduce future seismic activity from future fracking work.
The Alberta Geological Society and Alberta Energy Regulator also called for further study of what’s causing the increase in seismic activity. “At least 13 new clusters of induced earthquakes are recognized,” the study said. “Our next steps were to better understand why this region may be susceptible to these events through comparisons to other regions where geological proxies for seismogenic potential have been identified.”
CBC says Vesta’s website lists 84 producing wells in central Alberta’s Joffre Duvernay shale oil basin. “Vesta operates in areas with potential for seismicity, and continues to take the necessary precautions to ensure compliance with Alberta Energy Regulator,” the company told CBC in an emailed statement last week. “Vesta has sophisticated monitoring equipment placed throughout its operating perimeter to detect seismic activity, and works with the AER as needed to report any detections of seismic events in the area.”
