When one thinks of earthquakes, what comes to mind is usually the vast fault line straddled lands of southern California or the great subduction zones off the coasts of Chile and Japan. Surely, it isn’t the cattle fields of Texas or the rolling plains of Ohio and Oklahoma. Natural disasters in the central and southern United States typically blow in with the winds in the form of deadly tornadoes and storms. Yet, thanks to the insatiable rush to tap every last drop of oil and gas from the depths of the earth’s crust, earthquakes are fast becoming the new norm in “fly-over country”.
Fracking involves shooting a mix of sand, water and chemicals deep underground to force natural gas and oil to the surface. The practice is employed in geological areas where typical extraction methods can’t be utilized. Depending on the size of the operations, fracking produces millions of gallons of water waste, which ends up being stored undergound in so-called injection wells. In 2012 fracking in the U.S. produced nearly 280 billion gallons of this chemically-laden fluid and the EPA reports there are over 155,000 oil and gas wastewater wells active nationwide. Geologists have long associated these deep wells with earthquakes.
Back in the 1960s the U.S. military injected chemical waste northeast of Denver, Colorado at the Rocky Mountain Arsenal station. From March of 1962 to September 1963 an average of 21 million liters were injected 3,600 meters below the earth’s surface monthly. While injections ceased for nearly a year, the military again resumed the practice in April 1965 through February 1966, only to be halted once earthquakes were reported at local seismic stations. After observing this earthquake activity before, during and after the injection of chemical water waste, researchers were convinced the pressurized injection had caused numerous tremors that would have otherwise not occurred.