The Ohio Department of Natural Resources (ODNR) determined that an earthquake in Youngstown, Ohio, which measured 4.0 on the Richter Scale on December 31, 2011, was caused by a Class II deep injection well. The Youngstown New Year’s Eve earthquake had been preceded by a number of minor seismic events between March and December of 2011 in the same area. ODNR based its determination regarding the cause of the earthquake on a number of factors. Its most important conclusion is the fact that the well had been improperly positioned over an existing fault line.
Other factors include:
- The New Year’s Eve earthquake originated in the same location as the Youngstown well with an epicenter on a fault line 9,842.5 feet below the surface, approximately the same depth as the well’s injection site.
- The seismic activities at the site coincided with injections to the well.
- Seismic activities did not begin in 2011 until after operation of the well had commenced.
- Other than the 2011 seismic activities, Youngstown is not a seismically active area.