Over a 28-hour span last week, Oklahoma was subjected to seven unique earthquakes. According to the U.S. Geological Survey, the events started Tuesday night, when five quakes struck the central part of the state. Then, two more earthquakes were measured during the early hours of Thursday morning.
All of the earthquakes were between magnitude 2 and 5, with no significant damage reported. The events were attributed to the disposal of wastewater used during hydraulic fracturing, or fracking processes, for the harvesting of oil. The recent surge in fracking activities has coincided with an increase in earthquakes in the Sooner state.
In 2010, the year fracking activities increased in Oklahoma, it experienced 41 registered earthquakes. According to the USGS, this number grew to 857 in 2016. During this same stretch, oil production in the state expanded by nearly 230 percent.
Scientists are linking the rise in earthquakes to the injection of large quantities of wastewater into wells deep below the state’s land surface. According to the USGS, most of the underground wastewater comes from oil and gas operations, which is created when clean water mixes with dirt, metals, and other toxins below the Earth's surface during extraction operations.
The contaminated water becomes too nasty to dispose of, so it’s shot deep into the ground (often more than a mile) where it seeps between layers of hard rock. The force and quantity of this wastewater has the potential to move previously stable rock, potentially causing earthquakes. Making things more complicated in Oklahoma, as opposed to other states using fracking, is the existence of ancient fault lines that have been quiet for quite some time.
The debate associated with hydraulic fracturing as a process for retrieving energy resources remains both heated and equally matched. Essentially, as the U.S. enjoys lower energy prices and a decreased dependence on imported oil and natural gas, the tolerance of environmental impact continues to be balanced against positive economic impacts.
Until a clearer solution is reached, the USGS estimates that geological events like the Oklahoma earthquakes will persist. What is unclear is if the magnitude of these quakes will increase if fracking continues at its current rate.