CALGARY - A report by British Columbia's energy regulator says a spate of small earthquakes could have been caused by a controversial natural gas extraction technique.
The B.C. Oil and Gas Commission investigated "anomalous" seismic activity detected in remote parts of the Horn River Basin, a gas-rich rock formation in the province's northeastern corner.
There, energy companies use a process called hydraulic fracturing, or fracking, to break the rock and free natural gas that's trapped inside.
The process involves injecting a mixture of water, sand and chemicals into the rock at high pressure and it's drawn criticism for its potential impact on groundwater sources.
The commission concludes the tremors took place shortly after fluid was injected close to pre-existing fault lines.
Only one of the 38 events recorded by Natural Resources Canada between April 2009 and December 2011 could be felt at the surface and there were no injuries or property damage reported.