Fact-Check: Can Fracking Cause Earthquakes?
The series of earthquakes that shook the Mahoning Valley last year were big news â not just because such tremors are an uncommon occurrence there, but also because they were found to have been a by-product of natural gas drilling. The finding has rattled many residents' comfort with the industry, which is on the cusp of enormous growth across Northeast Ohio. But are the fears justified? First Sign of Trouble Youngstown resident and geology professor Susie Beiersdorfer spends much of her free time organizing rallies against natural gas drilling. When a 4.0 trembler shook Youngstown last New Yearâs Eve, she was in the middle of putting together a brochure describing the risks of fracking â the process of fracturing rock formations deep underground to release and extract the gas. It was a coincidence she wouldnât let go to waste. âHad one panel left, looking into the jobs and the economy and those statistics and myths and the earthquake hit, so we used that last panel to say the creation of this flyer has been interrupted by an earthquake with the 4.0 and some of that information.â? Although there had been a handful of smaller tremors earlier that year, Beiersdorfer says the shaking from this one caught people off guard.
The glass of the downtown deli we were at just sort of moved back and forth, it didnât break. And the people walking in front just kind of stopped! It was definitely felt by everyone around there.
Concerns Turn to Disposal Well It turns out, investigators attributed the quake not to a fracked natural gas well, but to a well used to store wastewater from the fracking process, called an injection well. David Zeng is chair of the civil engineering department at Case Western Reserve University. He says the fault lines that cause earthquakes are usually located more than twenty miles below ground. Oil and gas wells where fracking occurs are much shallower - only one or two miles deep - and typically wonât trigger an earthquake. âOf course during the hydro-fracking process, you may feel a ground vibration, but the ground vibration is relatively small, itâs not going to cause any noticeable damage to structures," Zeng says. But, Zeng says the injection wells used to store the used waste water from fracking are a different story. âWhen you use injection wells, typically you are injecting waste water into the ground, so you want it really to go deep so that it wonât by any chance come back to affect your aquifer, your ground water. So typically it goes pretty deep - several miles."
When you go several miles deep, then you can touch the fault that can cause an earthquake.
A Statewide Issue The nearby well blamed for the New Yearâs Eve quake and several smaller ones was immediately shut down, and the Ohio Department of Natural Resources placed a moratorium on using similar wells within a seven mile radius. But, statewide the use of more than 170 injection wells continues. This summer, Governor John Kasich issued new regulations to better monitor wells and test their likelihood of triggering earthquakes. While the regulations may help, itâs the unknowns that still concern environmentalists and activists like Susie Beiersdorfer. She says scientists havenât studied the geology underneath Ohio well enough.
And if there is a fault, a non-documented, undiscovered fault, it could trigger an earthquake.
Drilling Continues More injection wells are on the drawing board in Ohio to accommodate the needs of and drillers from out-of-state â mainly Pennsylvania and West Virginia â who ship their wastewater here for disposal. Currently thatâs where most of Ohioâs buried wastewater comes from. Julie Shemeta, a geophysicist who consults with drilling companies about triggering earthquakes, says itâs hard to predict just what that impact will be. âWe know that seismic activity has been pretty rare, and that it should continue to be rare. But the long term effects of significant increases in the number of waste water disposal wells, for induced seismicity, we really donât know," Shemeta says. One thing that is for certainâthe fracking activity isnât going to let up any time soon. Over one hundred fifty horizontal gas wells have been drilled in the Utica Shale since 2009, and the state is on track to review permits for 33 new injection wells later this year.