Residents of Fox Creek felt the ground tremble on January 12, 2016. The reason: a 4.8 magnitude (ML) earthquake just 35 km from the northern Alberta town.
The quake was the fourth over 4 ML to shake the area in the past year, all linked to hydraulic fracturing in a province that, traditionally, has been relatively quiet on the earthquake front.
When it hit, seismologists at the AER’s Alberta Geological Survey Branch (AGS) were assessing data from previous earthquakes in the Fox Creek area as part of a formal study into “induced seismicity,” earthquakes that are triggered by human activity. The latest earthquake would provide them with even more data to analyze.
The AGS is using data from more than 53 monitors that measure seismic activity across the province, and the January event showed up on monitors almost immediately.
The activity also caught the attention of area residents, the media, and Alberta Premier Rachel Notley, who asked the researchers to provide an interim report this spring. The study’s final report is due to be published in November 2016.
“Our initial findings indicate a strong link between geological features in the area, for example faults and ancient fossil reefs, and induced seismicity,” said AGS geoscientist Todd Shipman, manager of the Landscape and Geological Hazards Group.
“We need to continue to study the links between hydraulic fracturing operations, geology, and geomechanics and their effects on induced seismicity,” said Kristine Haug, AGS geological engineer. “This information will be included in the final report.”
And while none of the earthquakes linked to hydraulic fracturing have caused any impact to infrastructure or the environment, energy operators in the area continue to be bound by AER’s Subsurface Order No. 2 when hydraulically fracturing in the area.
Using a “traffic light” protocol, licensees fracturing in the Duvernay Zone in the Fox Creek area must monitor seismic activity and report any earthquakes within 5 km of their wells during hydraulic fracturing operations. They must also have a response plan and be prepared to apply that plan to any induced seismicity above 2.0 ML.
If monitoring picks up an earthquake of 4.0 ML or greater, they must immediately cease operations and report it to the AER. They will not be allowed to resume operations without AER approval.
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The fracing around Lacombe is leaving water table.