Of course I’ve heard of Fracking and even have a reasonable idea of how the process works, but when Science magazine published an article on Injection-Induced Earthquakes, I thought I would look into it just a bit more.
The idea behind Hydraulic fracturing, or ‘Fracking’, is old – dating back to the 1860s, yet it only came into large scale industrial use in the late 1940s when Halliburton became the first company to use this technique to improve their harvest of natural gas.
The New York Times defines Fracking as “… horizontal drilling [that] has enabled engineers to inject millions of gallons of high-pressure water directly into layers of shale to create the fractures that release the gas. Chemicals added to the water dissolve minerals, kill bacteria that might plug up the well, and insert sand to prop open the fractures.”
In 1974, congress passed the Safe Water Drinking Act, which required permits for injecting fluid into the ground (42 U.S.C. , Chapter 6A, Subsection XII, Part C) in order to – obviously – protect underground waters from contamination before they are harvested for drinking. This didn’t stop fracking, but it did temper the method’s growth and put the Environmental Protection Agency, charged with upholding this law, against the Department of Energy, that was (in 1986) exploring unconventional methods of drilling, including horizontal drilling techniques.
1999 saw the use of high pressure treatments characteristic of today’s Fracking methodology being used to harvest natural gas from previously inaccessible shale sources in Texas. However, the EPA issued a statement in 2004 pointing out that Fracking fluids are toxic and are left behind in the soil following the process, but that it appeared to pose little risk to contaminating ground water.
[The] EPA retained the right, however, to conduct additional studies in the future. As a precautionary measure, the Agency also entered into a Memorandum of Agreement in 2003 (PDF) (9 pp., 331 K, about PDF) with companies that conduct hydraulic fracturing of CBM wells to eliminate use of diesel fuel in fracturing fluids.
The next year (2005) Congress moved to “amended the SDWA definition of “underground injection” to exclude underground injection of fluids or propping agents, other than diesel fuels, in hydraulic fracturing activities related to oil, gas, or geothermal production activities.” This effectively removed the risk that the EPA could intervene in commercial Fracking and the business boomed. Since that time a number of efforts have been made to slow the expansion of Fracking or to revisit the technique’s environmental impact.
I did not want to get into the discussion of environmental effects of Fracking that are central to the EPA discussion above. Instead, I thought it would be a good opportunity to simply present the data from the Science article on the increased number of moderate earthquakes since the deregulation of 2005.
The dotted line shows a steady number of earthquakes occurring prior to 2000. The red line shows the actual number of (cumulatively) earthquakes occuring since about 1970.