The BC Oil and Gas Commission studies and monitors seismicity as it relates to oil and gas activities. A seismic event takes place when rocks deep underground shift. These rocks slide past each other along natural breaks in the earth’s crust, known as faults. The shifting of rocks in these spaces is referred to as fault movement, which releases stored energy.
Some of the energy is released in the form of seismic waves, which can cause the ground to shake. The amount of energy released by a seismic event is measured by its Magnitude.
Two types of seismicity are natural seismicity and induced seismicity. Natural seismicity, which is considerably more common, is largely caused by tectonic activity. The majority of these earthquakes occur along plate boundaries, but natural seismicity can occur anywhere in the world.
There are millions of seismic events each year around the world. On average, more than 4,000 earthquakes are recorded in Canada annually. The vast majority of these are recorded under a Magnitude 3.0. Events that are greater than Magnitude 3.0 may be felt at the surface.
Induced seismicity, which is what the Commission primarily studies, refers to typically minor tremors caused by human activities. Most induced seismicity occurs at very low magnitudes. None of the recorded events resulted in any injuries, property damage or loss of wellbore containment outside of the formation. Induced seismicity can be caused by blasting, mining and oil and gas operations. In northeast B.C., induced seismic events have been linked to oil and gas operations.
The Commission has identified two causes of induced seismicity related to oil and gas activities – wastewater disposal and hydraulic fracturing. These are described in detail in the Induced Seismicity section.
Induced seismicity typically refers to minor tremors caused by human activities.
The Commission has identified two causes of induced seismicity related to oil and gas activities – wastewater disposal and hydraulic fracturing. It released two related, detailed studies on induced seismicity caused by oil and gas activities in 2012 and 2014.
The Commission monitors the Canadian National Seismograph Network (CNSN) for seismicity, and has worked collaboratively with Natural Resources Canada, GeoscienceBC and the Canadian Association of Petroleum Producers to upgrade the network in northeast B.C. This work has resulted in an additional nine seismograph stations, bringing the northeast total to 11. For more information on monitoring, click here.