Environmentalists have long criticized fracking because of its potential effects on the environment, including alleged dangers to the drinking water supply.
But lately, some scientists are making the controversial claim that the dangers of fracking go far beyond these hazards. They say fracking may actually cause earthquakes.
"The controversial practice of fracking appears to be linked to all the earthquakes in a town in Ohio that had no known past quakes, research now reveals," LiveScience recently reported.
For clarity's sake, Reuters provides a quick definition of fracking: It "involves pumping millions of gallons of water, sand and chemicals underground to fracture shale rock and release oil or gas. Much of that water returns to the surface and is stored in lined pits or closed tanks for recycling or injection in underground storage caverns offsite."
Can those injections cause earthquakes? Some researchers see a correlation. Youngstown, Ohio, had never experienced an earthquake before January 2011, LiveScience said. Only a month before its first earthquake, Youngstown had become a fracking site. In the following year, Youngstown had 109 earthquakes. The site was shut down after one of the quakes.
But which part of the process causes earthquakes? NPR said some researchers believe that it is not exactly fracking itself, but rather the disposal of fracking-related wastewater that leads to quakes. Here's a description of the disposal process in question: "The fluids used in fracking and the wastewater that come back up the well [are] disposed of by injecting it into disposal wells deep underground. This is generally regarded as the safest, most cost-efficient way to get rid of it."
But how safe is it, really? Researchers say this critical step, disposing of drilling fluid, is causing earthquakes. In other words, the fracking itself is not frequently seen as an earthquake catalyst. "Hydraulic fracturing almost never causes true earthquakes," Cliff Frohlich, a seismologist from the University of Texas, recently said in The Associated Press. "It is the disposal of fluids that is a concern."
After all, if the injection part of the process were a major culprit, Texas would be getting more earthquakes than it does, he said. The state has 10,000 injection wells. "Texas would be famous as a state that just rocks with major earthquakes," Frohlich said. "That is not true. If injection wells were hugely dangerous, we would know."
Still, he is not afraid to go a little beyond that, noting that in some instances, the fracking itself causes quakes.
“In the last year there have been three well-documented earthquakes that occurred during the frack job and were probably related to fracking." he said. "They were all small earthquakes – of a magnitude of 2 or 3." But he diminished the urgency of this problem. "Considering, that there are millions of frack jobs, fracking-related earthquakes are so rare,” he said.
Image credit: "Earthquake!," © 2008 digialsadhu, used under an Attribution-NonCommercial 2.0 Generic license: http://creativecommons.org/licenses/by-nc/2.0/deed.en