A series of earthquakes in March in Ohio were caused by hydraulic fracturing and horizontal drilling for natural gas, researchers concluded.
Scientists with Ohio’s Miami University found that the fracking hit an ancient, previously unknown fault, The Columbus Dispatch reported.
{mosads}That caused a magnitude 3.0 earthquake on March 10 that was felt miles around. It also caused 76 less severe earthquakes in the surrounding days.
The researchers compared fracking data from the state’s drilling regulator in the region to the 77 earthquakes and found that the quakes matched with certain stages of the fracking process, they said Monday.
The study found a vertical, east-west fault line along which the earthquakes coincided, the Dispatch said.
The quakes “occurred in the Precambrian basement, a very old layer of rock where there are likely to be many pre-existing faults,” researcher Robert Skoumal said in a news release.
“This activity did not create a new fault, rather it activated one that we didn’t know about prior to the seismic activity.”
Fracking, an oil and gas extraction process that involves pumping fluid into the ground at high pressure, is rarely linked to earthquakes, the study said. But the number of fracking-linked earthquakes has grown in recent years as the practice has grown, including in Oklahoma.
Researchers concluded that governments, geologists and drillers should work together more closely to identify ancient fault lines and avoid fracking near them.