As the adverse effects associated with hydraulic fracturing grow more apparent in human, animal and environmental health, so too do they become of growing concern for the earth as a whole. The process of fracking is inherently destructive, jeopardizing the health of ecosystems and their inhabitants at every phase. The effects of the toxic slew of chemicals when injected into the earth do not just affect health, but have also been linked to the advent of low magnitude earthquakes.
Considering the disruptive nature of the process, involving the drilling of a vertical well many kilometers beneath the earth’s surface, followed by directionally drilling horizontally to expose shale to fracturing fluids, the resulting increase in seismic activity near fracking sites may not come as a surprise. Studies exploring the connection between hydraulic fracturing and earthquake activity have determined the cause of the quakes to be both the initial injection of fracturing fluids, and more commonly, the reinjection of wastewater.
The injection of fluids into the earth’s subsurface in the initial phase of fracking can lubricate existing fault zones, helping adjoining rocks to slip along the fault boundary (Palliser, 2012). This movement that the fluids facilitate, results in an earthquake. Earthquakes also occur as a result of the reinjection of wastewater fluids into sandstone at a depth equal to that of the original well causing slippages of faults at the injection site (Fischetti, 2012).
This correlation between fracking activity and seismic activity is evident in Oklahoma, witnessing an increase in the number of earthquakes occurring near hydraulic fracturing sites due to both drilling and waste injection (Clary, 2015). Further research into the causes and effects of these earthquakes has been linked to the operations of four Oklahoma high volume wastewater wells, resulting in earthquake activity up to 35 kilometers away (Clary, 2015). Studies linked to Oklahoma’s recent burst in seismic activity, including several earthquakes of over 3.0 magnitude within the first half of 2014, has led to the conclusion that earthquake events such as these can produce seismic events near wastewater wells “even a hemisphere away” (Clary, 2015).
Oklahoma is not the only state experiencing the groundshaking effects of fracking. In December 2011, the state of Ohio was shaken by two earthquakes occurring within .8 kilometers from the hydraulic fracturing injection well. Earlier that year, nine earthquakes shook the state between March and November, all within an 8 kilometer radius of a wastewater injection well. It is estimated that Ohio will continue to experience earthquakes, even if fracking operations are suspended due to the destructive process of wastewater disposal (Fischetti, 2012).
Sources and Further Reading:
- Clary, R. (2015). THE HUMAN IMPACT ON EARTHQUAKES: NATURAL FRACTURING VERSUS FRACKING.Science Scope, 38(5), 24-31. Retrieved from http://search.proquest.com/docview/1640566146?accountid=14771
- Palliser, J. (2012). Fracking fury.Science Scope, 35(7), 20-24. Retrieved from http://search.proquest.com/docview/927534588?accountid=14771