A new scientific study authored by the Geological Society of America indicates Oklahoma’s 2011 record-setting 5.7 magnitude earthquake was “potentially related” to the hydraulic fracturing in the state, which injects a formula of water and chemicals into the earth’s surface.
In 2011, five earthquakes in the U.S. were registered at magnitude 5 or greater, the report states. At the same time, the volume of fluid injected into the subsurface by the oil fracking industry continues to rise, highlighting the correlation between earthquake intensity and fracking frequency.
The study gives greater strength to the argument among fracking opponents, who point to the increased practice of fracking and the growing frequency of earthquakes in the United States. In 2001, the U.S. averaged 29 earthquakes with magnitudes of 3 or greater — that number increased in 2011 to 134, along with the increase of fracking wells dotting the U.S. map.
Speculation grows with each report
Speculation followed Oklahoma’s 2011 quake, with the scientific community claiming both there could — and could not — be a link between fracking and increased earthquakes in the state. Stanford University Geophysicist told the Associated Press in 2011 that the state had a fault line, leaving the possibility that it occurred naturally. Yet other studies linked an increase of fracking to an abundance of quakes in the state.
As noted by TIME’s Bryan Walsh, an Oklahoma State Geological Survey report concluded that more than 50 small quakes, ranging in magnitudes between 1.0 to 2.8, were in fact linked to fracking.
Oklahoma’s fracking industry is old, in terms of fracking operations in the U.S., considering it began 18 years ago. In 2012, a quarter of all jobs in the state were somehow tied to the energy industry, according to the Bureau of Labor Statistics. In 2011, Oklahoma fracking led the U.S. market last year, with $5 billion worth of sales, according to Bloomberg News.
In June 2012, the National Research Council released a report indicating hydraulic fracturing “has a low risk for inducing earthquakes that can be felt by people.” While it didn’t rule out the link between fracking and seismic activity, it did claim there was a need for large-scale projects to study the theory.
In December 2012, scientists gathered in San Francisco for the Geophysical Union meeting, during which evidence was put forth linking the disposal of waste water from fracking to increased incidents of earthquakes. Jessica Leber of Technology Review reported that scientists looked at Oklahoma, Texas and Colorado, states that have seen booms in both fracking activity and earthquakes, as prime examples.
During that time, scientists also highlighted the Oklahoma 2011 earthquake, claiming it was “likely caused by fluid injection,” citing studies by the University of Oklahoma, Colombia University and the U.S. Geological Survey.
Yet still, there were calls to further examine the issue, with skeptics claiming the need for a widespread study before determinations were made.
A breakthrough in studying the fracking/earthquake link
What’s unique about this most recent study is the longevity of the fracking industry in Oklahoma. The state’s oil fields have been subject to hydraulic fracturing processes for the last 18 years, allowing scientists to get a glimpse into the long-term impact of fracking.
“Subsurface data indicate that fluid was injected into effectively sealed compartments, and we interpret that a net fluid volume increase after 18 years of injection lowered effective stress on reservoir-bounding faults,” it states.
Aside from the link between increased earthquake frequency and intensity and a spike in the fracking industry, the report also looks at the proximity of fracking wells to earthquake rupture planes. In the case of Oklahoma’s record setting quake, the initial rupture plane was less than 200 meters from an active “injection” well.
A report released a year earlier by the U.S. Geology Survey indicating the U.S. has experienced an abrupt increase of earthquakes with a magnitude of 3 or greater. From 1970 through 2000, the rate of earthquakes with that magnitude occurred, on average, 21 times per year. In 2011, that number reached 134.
“The acceleration in activity that began in 2009 appears to involve a combination of source regions of oil and gas production, including the Guy, Arkansas region, and in central and southern Oklahoma,” the study states.
According to the industry, there’s no plan to stop. Greenpeace indicates there are 1.2 million wells already in place, with plans to increase presence with at least 100 new wells each day.