Researchers at the University of Calgary have figured out how hydraulic fracking is causing earthquakes in Alberta.
A recent study has found two potential reasons a quake could occur; one which can lead to seismic activity weeks after the actual fracking takes place.
These quakes have been primarily focused on an area about 30 kilometers west of Fox Creek, northwest of Edmonton.
Researchers collected and analyzed seismic data dating back to the winter of 2015, when the first earthquake larger than a magnitude 4 was recorded in Fox Creek. Data was compiled from private and public seismograph stations, monitors installed after the earthquake and a comprehensive database of hydraulic fracturing data from each well in the area.
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Seismologist David Eaton says some of the earthquakes have been caused by slippage along previously unknown faults deep in the earth.
Others stem from oilsands fluids that can cause long-term pressure changes in underground rock formations. The changes can cause quakes for weeks or months after the fluid injection stops.
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Eaton says he believes the findings could change the way fracking is regulated.
“It’s our hope that this work is going to contribute to science informed regulations, so that we can take this knowledge and use it to improve the existing regulations. We’re also hoping that it will improve both risk assessment and mitigation strategies by industry,”Eaton said.
Hydraulic fracturing involves injecting a high-pressure slurry of mainly water and sand into underground formations, creating a network of small cracks or fractures through which oil and natural gas can flow into wells.