A single fracking wastewater well triggered 167 earthquakes in and around Youngstown, Ohio, during a single year of operation.

That’s according to a study published in the Journal of Geophysical Research by Won-Young Kim, a researcher at Columbia University. Earthquakes had never been recorded at Youngstown before 2010. Then, at the end of that year, frackers started pumping their waste from Marcellus Shale drilling projects into the 9,200-foot deep Northstar 1 injection well. Within two weeks, the area had experienced its first quake.

From January 2011 to February 2012, the area was jangled by an average of nearly 12 earthquakes every month. Many of them were imperceptible to residents, but they grew in intensity over time and ranged up to a home-rattling magnitude-3.9 temblor on the final day of 2011. That was one day after the injection well was last used for dumping waste; the Ohio Department of Natural Resources had ordered it shut down because of the escalating flurry of earthquakes. By that time, 495,622 barrels of wastewater had been crammed into it.

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After the injection well fell into disuse, the string of earthquakes quickly tapered away.

Kim found that the frequency and intensity of earthquakes in the area was closely linked to the daily pressure levels in the well. He also compared the seismic profile of the region with the epicenters of each of the earthquakes and concluded they occurred either at the well or along a fault line to which it was connected.

“We conclude that the recent earthquakes in Youngstown, Ohio were induced by the fluid injection at a deep injection well due to increased pore pressure along the preexisting subsurface faults located close to the wellbore,” Kim wrote in the paper.

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The discovery builds on a growing body of scientific evidence linking the use of fracking wastewater injection wells to earthquakes. That includes a string of quakes in central Oklahoma in late 2011, including the most powerful ever recorded in the state, a frightening magnitude 5.7.

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