The Ohio Department of Natural Resources (ODNR) is tightening permit conditions for horizontal drillers after a report from state geologists found a "probable connection" between hydraulic fracturing and a string of small earthquakes near Youngstown, Ohio.

The ODNR's new rules require companies drilling within 3 miles of a known fault or an area of seismic activity greater than 2.0 magnitude to install sensitive seismic monitors to detect future disruptions. If the monitors detect seismic activity in excess of 1.0 magnitude, drilling at the site will be halted pending an investigation. And if that investigation establishes a probable connection between the seismic activity and hydraulic fracturing process, all drilling operations will be suspended. These rules will apply to both existing and future drilling permits issued by the agency.

The announcement comes a month after Ohio suspended Hilcorp Energy's drilling operations in western Ohio after five seismic events occurred in the vicinity. The strongest event had a magnitude of 3.0. After investigating potential causes of the quakes, ODNR scientists speculated that "sand and water injected into the well during the hydraulic fracturing process may have increased pressure on an unknown microfault in the area."

While environmentalists praised the ODNR's announcement, Thomas Stewart of the Ohio Oil and Gas Association urged caution, saying that the organization believed the seismic activity near Youngstown "was a rare and isolated event that should not cast doubt about the safety of hydraulic fracturing."

Other states that have seen increased earthquake activity during the recent shale gas boom—including Oklahoma, Texas, and Kansas—may soon follow in Ohio's footsteps by imposing additional requirements on drillers that operate close to known fault lines or areas of high seismic activity.  It remains to be seen whether federal regulators will likewise tighten regulations to account for the growing concern over earthquakes related to hydraulic fracturing. We will continue to update this blog with any further developments.

Additional coverage of this story can be found here, here, and here.

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