Oklahoma is no stranger to small earthquakes, but a series of larger earthquakes in 2011, including one that reached a 5.7 magnitude, had some people wondering whether hydraulic fracturing had anything to do with the shifting earth. Now, a group of scientists have published a report concluding that the natural gas drilling technique could be linked to the quake. As the US gears up to begin selling gas produced by fracking to the UK, this new information indicates that we should be questioning whether the damage caused by the process is worth the profit.
Fracking has been known to cause small-scale earthquakes in the past, but nothing of this size or duration, and the small rumbling usually occurs within a few weeks of wellhead injection. So it was generally accepted that fracking had no role in the 2011 earthquake. But the study, published by Katie M. Keranen, Heather M. Savage, Geoffrey A. Albers and Elizabeth S. Cochran, indicates that it isn’t the initial process of injecting the wellhead that can cause earthquakes, but rather it’s the damage caused by injecting wastewater underground.
In this case, wastewater injected almost 20 years ago during the fracking process “lowered effective stress on reservoir-bounding faults.” In 2012, scientist at the US Geological Survey found that seismic events in the area had increased dramatically since 2009, but made no definitive decision on whether fracking was to blame. The Oklahoma Geological Survey maintains that the earthquake could have been the result of natural causes and further study is required before any definitive determination can be made. Beyond the possibility of earthquakes, fracking is known to contaminate ground water and pollute the environment.