Tracing Links Between Fracking and Earthquakes

In society’s ever-deeper dig for energy, one of the risks is causing the Earth to move.

The most recent dramatic example came on New Year’s Eve outside of Youngstown, Ohio. A 4.0 earthquake was the last and largest of a series of temblors that prompted state officials to halt nearby underground disposal of wastewater from hydraulic fracturing for natural gas. There were no reports of serious damage or injury, but the impact in the energy world could be significant.

In the past two years, there have been three other cases in the United States and one in England (see map) where regulators or scientists traced links between seismic activity and fracking, or the disposal of briny and polluted fracking wastewater through underground injection. Ohio Department of Natural Resources Director Jim Zehringer took pains during a news conference to emphasize that the seismic events near Youngstown were “not a direct result of fracking,” but of the wastewater disposal.

But since fracking for natural gas requires about 4 million gallons (15 million liters) of water, a large volume of which will return to the surface at well completion (with more coming up over the life of the well), dealing with its disposal is a fairly important indirect result.

(Related interactive: “Breaking Fuel From Rock With Water“)

And in the case of quakes in Garvin County, Oklahoma and Lancashire, England, it is the fracking itself that is suspected of stimulating seismic activity.

The new wave of natural gas drilling with high-volume hydraulic fracturing is not the first or only energy development that has been linked to seismic activity. The most damaging earthquake in Australia’s history, in 1989, has been linked to the cumulative impact of 200 years of coal mining. University of Utah scientists have been researching the connection between coal mining and earthquake patterns in the Wasatch Plateau and the Book Cliffs.

But fracking is part of a new wave of energy development that involves injecting fluid underground under pressure. Fluid injection is also used in “enhanced oil recovery,” to force oil out of wells once thought to be too depleted for further development. And the technique is not limited to fossil fuel development. One of the high-potential renewable energy technologies–enhanced geothermal energy–requires stimulation of hot rock underground by water. A major geothermal project in Basel, Switzerland was shut down in 2006 after it generated earthquakes. There are also seismic concerns over one of the technologies that is a hope for addressing global warming: Carbon dioxide sequestration underground.

In a project that has been proceeding over the past year mostly under the radar, the U.S. National Academies of Science is expected to publish a study this spring on induced seismicity and energy technologies. “A potentially adverse side effect of subsurface fluid injection in all of these technologies is induced seismicity,” the NAS says. The study is clearly just a first step; it aims to identify what further research needs to be done to give policy makers information they need to develop safety guidelines on this new wave of energy projects.