When caused by humans, seismic activity (also called earthquake activity) is known as induced seismicity. Induced seismicity is associated with industrial processes including geothermal energy extraction, mining, dam building, construction, and hydraulic fracturing.
Earthquakes and Hydraulic Fracturing
Hydraulic fracturing, or “fracking,” forces fluid into rock layers deep underground in order to crack the rock and release oil or natural gas trapped inside. Hydraulic fracturing can cause induced seismicity (earthquakes). This usually occurs near where the rock is being fractured, 2,000 to 3,000 metres below ground.
Induced seismicity is usually recorded as microseismic events, which are rarely felt on the surface because of their low magnitude. Of the seismic events felt on the surface, most are below 3.0ML on the Richter scale — equivalent to vibration made by a passing truck. In rare cases, hydraulic fracturing has caused seismic events of 4.0ML to 4.8ML. Even at these levels, property damage or risk to public safety is unlikely.
Induced Seismicity Regulations
In parts of B.C. and Alberta, companies are required to monitor for seismic activity associated with hydraulic fracturing. Companies must also develop, and file with the regulator, a response plan in the event their operations trigger a seismic event. Any seismic event of 2.0ML or greater must be reported to the regulator. In the rare case an event of magnitude 4.0ML or greater occurs, hydraulic fracturing operations must immediately stop so an investigation can be conducted by the regulator. Operations may only begin again once the regulator has given permission.
Induced seismicity is regulated through both provincial and federal agencies.
Technical Research into Induced Seismicity
Geoscience BC, the BC Oil and Gas Commission, Natural Resources Canada and the Canadian Association of Petroleum Producers partnered to form the BC Seismic Research Consortium in 2012. The consortium performs ongoing monitoring and studies of induced seismicity in northeast British Columbia.