Research has been mounting for years to support the unprecedented connection between earthquakes and the hydraulic fracturing (fracking) process of blasting millions of gallons of sand and chemical-laden water deep into shale rock to remove entombed gas and oil.
As the fracking boom has accelerated it has raised alarms for risk to human health, water contamination, dangers to wildlife and the environment.
The US currently has more than a million oil and gas extraction sites that utilize the fracking process.
But geologists released news from Ohio on Friday, according to Associated Press, that links tremors to fracking deep under the Appalachians, which launched new permit requirements on an industry barely regulated on the federal level.
This announcement marks the first time earthquakes have been linked directly to the fracturing process in Ohio and not to the disposal of wastewater as previously reported in other studies. There were five seismic events recorded in March alone that were strong enough to be felt by people in local communities.
Experts cautioned that oil and gas operations across the nation involve various types of rock formations, so the Ohio studies may not apply to all fracking-related projects.
Many states have already formed consortiums to study Ohio’s findings and continue discussions on the dangers of fracking.
Previous findings by the US government have connected tremors to oil and gas extraction, including a 2011 2.8-magnitude quake in Oklahoma and the Canadian government studied the link between fracking and quakes from 2009 to 2011 that prompted new regulations.
After imposing a moratorium on the area of the March quakes, Ohio’s new permit restrictions will require the installation of seismic-monitoring equipment for all drilling sites within 3 miles of an established earthquake fault. Drilling activities would be immediately halted in the event of a 1.0 magnitude tremor or higher, for evaluation.
Oklahoma is another state that has been plagued with small earthquakes, although most have not been big enough to feel unless they were more than 2.5 magnitude, but the state has already broken its annual record from 222 quakes in 2013 to 253 this year, according to Seismologist Austin Holland of the Oklahoma Geological Survey.
“We have had almost as many magnitude 3 and greater already in 2014 than we did for all of 2013… We have already crushed last year’s record for number of earthquakes,” said Holland.
In December, Think Progress reported that scientists at Southern Methodist University in Texas linked a system of quakes to the injection of wastewater into the ground, which has been seen as the primary culprit between seismic activity and fracking after examining more than 50 quakes in an area near Cleburn, which had never been hit by quakes before.
“Because there were no known previous earthquakes, and the located events were close to the two injection wells and near the injection depth, the possibility exists that earthquakes may be related to fluid injection,” the authors write in their report.
Researchers also concluded that it could take several years for the fracturing process or the disposal of wastewater to initiate the onset of tremors.