B.C. regulator says fracking caused earthquakes near Fort St. John

The B.C. Oil and Gas Commission has blamed fracking for three earthquakes in northeastern B.C. last month.

The provincial regulator says the events 20 kilometres south of Fort St. John on Nov. 29 occurred because of fluid injections during hydraulic fracturing at a Canadian Natural Resources wellsite.

The events, which were felt but caused no surface damage, measured 3.4, 4.0 and 4.5 magnitude.

Fracking operations within the lower Montney formation, a major shale oil and gas resource near the B.C.-Alberta border, were suspended after the earthquakes and are to remain suspended at the multi-well pad,pending the results of a detailed technical review.

The commission says seven wells into the upper Montney formation had previously been drilled and completed by the Calgary-based company with no seismic events larger than magnitude 2.5 detected.

The immediate shutdown of operations is required when an induced seismic event in that region reaches or exceeds a 3.0 magnitude.

Hydraulic fracturing involves injecting water, sand and chemicals into a well under pressure to break up tight underground rock and free trapped oil and gas.