Hydraulic fracturing used to access oil and gas from rock and shale hasn’t caused “significant” earthquakes, according to a study by Durham University.
“Hydraulic fracturing is not a significant mechanism for inducing felt earthquakes,” Richard Davies, director of the U.K. university’s energy institute, said today in a statement. “The size and number of felt earthquakes caused by fracking is low compared to other manmade triggers such as mining, geothermal activity or reservoir water storage.”
Tremors aren’t the only concern about the method, known as fracking, according to a Greenpeace statement. “Communities have also expressed concern about noise, disruption, traffic, falling house prices and a general industrialization of the English countryside,” Lawrence Carter, an energy campaigner for the environmental group, said in the statement.
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Cuadrilla Resources Ltd. drilling caused two tremors in 2011 in northwest England, leading to an 18-month moratorium on fracking, which uses water, chemicals and sand to blast underground rock and release trapped fuel. The government lifted the ban in December and is preparing tax breaks to encourage drillers as it seeks to expand domestic energy sources amid declining North Sea fossil fuel production.
The Durham study of hundreds of thousands of fracking operations since 1929 found the process has the potential to reactivate dormant faults, the university said.
“We cannot see every fault underground and therefore cannot completely discount the possibility of the process causing a small felt earthquake,” Davies said. “But there are ways to further mitigate against the possibility; the oil and gas industry can avoid faults that are critically stressed and already near breaking point.”
Earthquakes caused by mining can range from 1.6 to 5.6 in magnitude and reservoir-filling can trigger tremors of as high as 7.9, according to the study. In comparison, fracking can cause movements of 1 to 3.8 magnitude, it said.
In the Netherlands, two quakes measuring 3.2 and 2.7 struck the gas-rich Groningen area in early February. The tremors near Blackpool in the U.K. two years ago were 2.3 and 1.5.