Fracking practices to blame for Ohio earthquakes

http://www.nbcnews.com/science/fracking-practices-blame-ohio-earthquakes-8C11073601

Charles Q. Choi LiveScience
Sept. 4, 2013

Wastewater from 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.

The practice of hydraulic fracturing, or fracking, involves injecting water, sand and other materials under high pressures into a well to fracture rock. This opens up fissures that help oil and natural gas flow out more freely. This process generates wastewater that is often pumped underground as well, in order to get rid of it.

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Before January 2011, Youngstown, Ohio, which is located on the Marcellus Shale, had never experienced an earthquake, at least not since researchers began observations in 1776. However, in December 2010, the Northstar 1 injection well came online to pump wastewater from fracking projects in Pennsylvania into storage deep underground. In the year that followed, seismometers in and around Youngstown recorded 109 earthquakes, the strongest registering a magnitude-3.9 earthquake on Dec. 31, 2011. The well was shut down after the quake.

Scientists have known for decades that fracking and wastewater injection can trigger earthquakes. For instance, it appears linked with Oklahoma's strongest recorded quake in 2011, as well as a rash of more than 180 minor tremors in Texas between Oct. 30, 2008, and May 31, 2009.

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