Fracking was the “probable” cause of a series of small earthquakes that shook northeast Ohio last month, state officials announced on Friday. This is the first time gas drilling in Ohio and local quakes have been linked. Previous studies have only found connections between the underground injection of fracking wastewater and tremors.
In March, Houston-based Hilcorp Energy was ordered to halt work at seven wells in Poland Township, near the Pennsylvania border after two small earthquakes, 3.0 and 2.6, rattled nearby residents. With no wastewater injection sites nearby, investigators focused on whether fracking itself had caused the ground to shake, and they now believe it did.
The news came as the Ohio Department of Natural Resources released strict new guidelines for monitoring seismic activity in the state.
The rules will require companies to install seismic monitors before beginning to drill within three miles of a known fault or in an area that has experienced seismic activity greater than a 2.0 magnitude. If seismic monitors detect a quake of 1.0 or more, regulators will suspend fracking and investigate whether drilling is connected to the quake. Humans can generally feel earthquakes of magnitude 3 and above.
A recent article in the Cleveland Plain Dealer pointed out that the threshold for halting drilling operations was low enough, at magnitude 1, that the Seattle Seahawks Fans might jeopardize drilling. At the NFL playoffs, 67,000 football fans at CenturyLink Field managed to create just such a tiny quake by stamping their feet. This talking point has already been adopted by those who oppose the new rules.
Ohio already has regulations against the disposal of fracking wastewater in certain counties where seismic activity has been a problem in the past. Since 2012 no wastewater has been injected underground within a five mile radius of a well in Youngstown after a series of earthquakes rocked the area in 2011.
The new rules may cause a regulatory quake felt in other states that have experienced an uptick in tremors as fracking operations expand. Oklahoma, Texas, Arkansas, and Kansas have all seen significant surges in seismic activity in recent years. Oklahoma has already had more magnitude 3 or higher earthquakes this year than in all of 2013. Before 2009, Oklahoma experienced about three quakes a year of magnitude 3 or more. Since 2009, earthquake activity in Oklahoma has consistently been about 40 times higher than the average of the previous 30 years.
A string of earthquakes in 2009 and 2010 in Cleburn, Texas has been linked to the injection of fracking wastewater into the ground. The area was hit by a group of more than 50 earthquakes in 2009 and 2010, but before 2008, the Fort Worth Basin of Texas had never experienced an earthquake.
To date, there have been only three other cases globally where fracking rather than wastewater disposal has been shown to have directly triggered a quake — in British Columbia, England and south-central Oklahoma.