A main purpose of this blog is to separate the real environmental impacts caused by gas drilling from demagogic attacks and to compare the strengths and weaknesses of natural gas to all our other energy choices. In the category of genuine environmental issues posed by gas production, put the siting of deep well injection facilities to dispose of drilling wastewater.
Indeed, the evidence is growing that injecting fluids deep underground can cause earthquakes. The latest study was done by University of Texas researcher Cliff Frohlich and focused on disposal wells in the Barnett Shale from 2009 to 2011. www.businessinsider.com/ut-study-sees-link-of-wells-quakes-2012-8. Frolich's study was published in the Proceedings of the National Academy of Sciences.
Using seismic monitoring equipment, Frolich identified a series of earthquakes, many too small to feel at the surface, that he concluded were associated with the disposal of drilling wastewater in the area. Frolich's work builds on other research and experience. For example, data from Arkansas and Ohio were sufficient to convince regulators there to close a small number of drilling waster water disposal wells.
To be clear, Frolich found that hydraulic fracturing itself was not causing the earthquakes he measured and recorded. Instead the seismic activity was associated with the permanent disposal of drilling wastewater deep underground in certain locations.
America has approximately 144,000 injection wells, where fluids are permanently disposed. Of that total, Pennsylvania has less than 10.
In Pennsylvania the Environmental Protection Agency administers the basic permit required to operate an injection well, but EPA has delegated this responsibility and authority to most states so that state agencies generally regulate injection wells.
Given that the seismicity risk associated with injecting fluids underground is sufficiently documented, regulators, industry, and the public should review siting regulations for these facilities. That is what Ohio's state officials exactly did after the Youngstown earthquake. And after the review, Ohio tightened regulations on deep well injection siting.
All states would be well advised to follow Ohio's example.