Generations of residents living in Youngstown, Ohio, never knew what an earthquake felt like. Then, hydraulic fracturing showed up nearby, and the ground started shaking. A lot.

From 1776 to 2011, Youngstown did not record a single earthquake. But from January 2011 to February 2012, 109 tremors were recorded, according to research (pdf) published in the Journal of Geophysical Research: Solid Earth. The strongest quake, on December 31, 2011, had a magnitude of 3.9.

What changed? In December 2010, a well was dug in neighboring Pennsylvania to pump wastewater produced by fracking.

The study’s authors compared the occurrence of the Youngstown earthquakes with activity in the well and found correlations between the two.

For instance, the first earthquake occurred 13 days after pumping began, and the tremors stopped shortly after state government officials ordered the well shut down in December 2011.

Additionally, the study reported that earthquake activity subsided on Memorial Day, the Fourth of July, Labor Day, and Thanksgiving…all periods when injection work at the well was not performed.

-Noel Brinkerhoff

To Learn More:

How Shale Fracking Led to an Ohio Town’s First One Hundred Earthquakes (Journal of Geophysical Research: Solid Earth)

Induced Seismicity Associated with Fluid Injection into a Deep Well in Youngstown, Ohio (by Won-Young Kim, Journal of Geophysical Research: Solid Earth) (pdf)

Ohio Government Confirms Earthquakes Caused by Fracking-Related Injection Wells (by Matt Bewig, AllGov)

Ohio Closes Fracking-Related Injection Wells after Earthquakes (by David Wallechinsky and Noel Brinkerhoff, AllGov)