Hydraulic fracturing triggered 400 small earthquakes in Ohio over three months in 2013, according to a paper in the journal Seismological Research Letters.
“The research reveals a previously undiscovered fault line approximately two miles below three horizontal gas wells near the town of Uhrichsville, Ohio,” Climate Progress reports. “In one instance, the researchers say they detected 190 tiny earthquakes below one of those wells during a 39-hour period, starting just after that well was fracked.”
The researchers said most of the quakes were too small to be felt, but stronger than they’d anticipated. “The findings have big implications for Ohio, which has some of the most strict rules governing fracking-induced earthquakes in the country,” Atkin writes.