Since records began in 1776, the people of Youngstown, Ohio had never experienced an earthquake. However, from January 2011, 109 tremors were recorded and new research in Geophysical Research-Solid Earth reveals how this may be the result of shale fracking.
In December 2010, Northstar 1, a well built to pump wastewater produced by fracking in the neighboring state of Pennsylvania, came online. In the year that followed seismometers in and around Youngstown recorded 109 earthquakes; the strongest being a magnitude 3.9 earthquake on December 31, 2011.