A division of the Ohio Department of Natural Resources (ODNR) will be receiving four new seismometers and plans to deploy at least two of them in the western and northwestern parts of the state, enabling it to monitor more of the state for seismic activity.

ODNR spokesman Eric Heis told NGI's Shale Daily on Monday that the Ohio Seismic Network (OhioSeis), part of the ODNR's Division of Geological Survey, will have six seismometers deployed across the state after it receives the two new units. Meanwhile, ODNR's Division of Oil & Gas Resources Management (DOGRM) has 19 seismometers set up, primarily in the eastern portions of the state that overlay the Marcellus and Utica shales.

"They're all linked together," Heis said. "If there are any seismic events, be it induced or natural, everyone will pick up on it. But OhioSeis is more focused on the general geology and seismic activity -- whether it's the recent earthquake in Michigan, or even Nepal. DOGRM regulates wellheads and will tell operators that are near a fault line -- or who could be near a fault line -- to put seismic monitors on their well pads. Obviously, that's not going to be looking specifically for natural events, but it's still in the same network."

Heis said Washington County, OH, had eight publically-owned seismometers deployed, the most of any county. That includes five with the DOGRM program, one with OhioSeis, one with the U.S. Geological Survey's NetQuakes program and one with the Central and Eastern United States Network (CEUSN), a long-term sub-array.

Washington County is also home to two Transportable Array stations, part of a network of 400 seismometers being deployed across the conterminous United States in a grid pattern. Heis said Ohio has 15-20 such arrays.

Heis added that there are 85 seismometers deployed across Ohio, including from private operators. The private units include eight owned by Hilcorp Energy Co. deployed in Mahoning County; four owned by American Water Management Services LLC (AWMS) deployed in Trumbull County; three owned by Buckeye Brine LLC deployed in Coschocton County, and three owned by K&H Partners LLC deployed in Athens County.

Regulators have been grappling with an increase is seismic activity, especially in the eastern regions of Ohio, home to the developing Marcellus and Utica shales. The latest issue cropped up in March when AWMS appealed an order by DOGRM to shut down its operations at an injection well in Trumbull County (see Shale DailyMarch 17).

On New Year's Eve 2011, an injection well was linked to a 4.0-magnitude earthquake in Youngstown (see Shale DailyJan. 4, 2012). In 2014, the ODNR issued statewide permitting requirements for horizontal oil and gas wells within three miles of a known fault (see Shale DailyApril 11, 2014). The rules were unveiled after ODNR linked stimulation operations at a Hilcorp pad outside Youngstown to a series of small earthquakes (see Shale DailyMarch 12, 2014March 11, 2014).