More Evidence Ties Ohio Quakes to Well Site

Pittsburgh Tribune-Review
4 January 2012
By Timothy Puko

A New Year's Eve earthquake in Youngstown occurred only 100 meters from another quake a week earlier, providing more evidence that an injection well in which a company was disposing wastewater from oil and gas drilling is likely causing the tremors, a seismologist studying the activity said on Tuesday.

Eleven earthquakes have struck the area since March, including the strongest yet -- a 4.0 magnitude -- on Saturday. The quakes have been getting larger over several months, and all happened near the Northstar Disposal Services waste-injection well. That means drilling fluid disposal there probably caused them, said John Armbruster, a seismologist at Columbia University hired by the state of Ohio.

The shaking could continue for months before the underground pressure dissipates, said Armbruster, who is helping state researchers collect and study the data. His team is trying to add more instruments, record smaller quakes and study injection patterns at the well, which could take months, he said.

The Ohio Department of Natural Resources and Gov. John Kasich's office say no conclusive evidence links the seismic activity to the injection well, but they agreed to shut it down as a safety precaution and expanded a moratorium on nearby operations set to open after Saturday's quake.

If the disposal well is causing the earthquakes, it's probably because an unknown fault turned out to be nearby, Armbruster said. Fluid could be seeping from the well bottom down into the fault. That would essentially work like a hydraulic jack, pushing the fault walls apart, leading them to slip and the earth to shake, he added.

Pennsylvania gas drillers rely heavily on Ohio injection wells for disposal of drilling waste, according to Pennsylvania Department of Environmental Protection records. Chevron, Rex Energy Corp., EOG Resources Inc., Consol Energy and Vista Resources Inc. all used the site that was shut down, according to Pennsylvania records.

None of the companies detailed its alternative disposal plans. EOG has made alternate arrangements for disposal and does not expect any harm to its Marcellus shale operations, but the company gave no further details in an e-mailed statement.

Timothy Puko can be reached at tpuko@tribweb.com or 412-320-7991.