According to a study described in the March 2016 edition of the journal Seismological Research Letters, hydraulic fracturing is linked to most induced earthquakes in the Western Canadian sedimentary basin. The study looked at data for 12,289 wells which had been hydraulically fractured, 1,236 waste water disposal wells and magnitude 3 or larger seismic events in Alberta and British Columbia that occurred between 1985 and 2015. Their analysis found that 39 hydraulically fractured wells and 17 wastewater wells could be linked to earthquakes of magnitude 3 or higher.
The study also confirmed that most seismicity in Alberta and B.C. was caused by humans, with 60% of the quakes linked to hydraulic fracturing, 30-35% from disposal wells and 5 – 10% from natural tectonic origins.
This finding is different than in the U.S. where waste water disposal wells are considered by some to be behind human-caused earthquakes.
The research also shows that very few hydraulic fractured wells cause earthquakes, with just 0.3% of the wells linked to a magnitude 3 or greater seismic event. A magnitude 3 earthquake may be felt by some people but very rarely cause damage.