The Alberta Energy Regulator is moving to restrict oilfield fracking activity near the Brazeau Reservoir in west central Alberta as a precaution following a 4.4 magnitude earthquake in the area in March.

The AER says hydraulic fracturing operations targeting the Duvernay underground formation or deeper are prohibited within five kilometres of the Brazeau dam infrastructure.

Hydraulic fracturing or fracking — where water, sand and chemicals are injected under high pressure to break up tight rock and free trapped oil and gas — is also banned for shallower operations within three kilometres.

Oilfield firms that engage in hydraulic fracturing within five kilometres of the dam must report any seismic events greater than 1.0 magnitude and operations must cease if any event of 2.5 magnitude or greater is detected, the AER says.

The epicentre of the earthquake in March was estimated to be about 32 kilometres northwest of Rocky Mountain House but it was not immediately linked to fracking activity. It was strong enough to be felt by local residents but no damage was initially reported.

A 4.6 magnitude earthquake a week earlier was felt in Red Deer and Sylvan Lake in central Alberta and prompted the AER to order producer Vesta Energy Ltd. to suspend fracking at its well site, report all previous seismic activity and file a plan to eliminate or reduce future seismic activity from fracking.