Hydraulic fracturing, or fracking, is the process in which water, chemicals and sand are injected at high pressure to split apart rock thousands of feet below Earth’s surface and release oil or natural gas. And it’s a controversial practice.
Opponents reject the practice of fracking due to a host of environmental concerns, including pollution and freshwater contamination, while industry groups tout the jobs and economic prosperity that fracking can offer.
In this debate, opponents have also claimed that fracking increases the risk of triggering nearby earthquakes. And they now have some scientific research to support that position. Scientists from the University of Calgary in Canada published a paper in the journal Science that attributes a recent spate of earthquakes in Alberta to hydraulic fracturing. The researchers say fracking induced earthquakes in two ways. The first was by the increase in pressure during the fracking process itself. The second was a result of pressure changes brought on by the lingering fracking fluid after the fracking process was completed.
David Eaton, a professor of geophysics at the University of Calgary and co-author of the paper, told the New York Times that “the key message is that the primary cause of injection-induced seismicity in Western Canada is different from the central United States.”
Scientists in the United States have maintained that fracking-induced earthquakes in this country are uncommon. Instead, they say most of the induced earthquakes in Oklahoma and other places have been caused by the burial of wastewater from all sorts of oil and gas wells. During this process, pressurized wastewater is injected underground into disposal wells drilled into rock. This can cause pressure changes in the surrounding rock formations and lead to earthquakes.
Researchers hope these findings – and these differences – will help regulators find ways to avoid induced earthquakes in the future.
Photo, posted October 11, 2010, courtesy of Care of the Earth via Flickr.