Largest slow-slip earthquake directly linked to fracking recorded in Western Canada

Fracking infographic

Western Canada's largest slow-slip earthquake believed to correlate to hydraulic fracturing operations has been detected by a team that included University of Calgary researchers.

The collaborative study, involving research teams in both Canada and China, has found evidence linking two 'slow-slip' earthquakes in northeastern B.C. to 'fracking' in the area.

The larger of the two earthquakes, the equivalent of a magnitude five seismic event, took place over several days and satellite measurements indicated a few centimetres of ground movement. No shaking was detected by seismographs in the area.

"This is the first time that significant slow-slip events associated with hydraulic fracturing have been directly detected," explained Dr. Thomas Eyre, PhD, lead author of the study and a geoscience research associate with the University of Calgary's faculty of science. "Naturally occurring slow earthquakes have been widely documented. In these scenarios, slip occurs along a fault, just like regular earthquakes, but much more slowly, so that no detectable shaking occurs.”

The previous record for a suspected hydraulic fracturing-induced earthquake in Western Canada was the equivalent of a magnitude 4.55.

According to researchers, most slow-slip earthquakes are naturally occurring and have minimal impact on the ground surface, but there's reason to believe they're much more common than previously thought.

"Since ground-motion from slow-slip earthquakes occurs over a longer time span, improved understanding of this process could have profound implications for future risk analysis," said Dr. David Eaton, PhD, a geoscience professor in the faculty of science.

In addition to the U of C team, the study included research from Natural Resources Canada, the Geological Survey of Canada and the University of Victoria, as well as participation from China's Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory.