USGS Links Hydraulic Fracking to Earthquakes

As someone who loves wilderness hiking and is an admitted map-freak, I have been a fan of the United States Geological Survey (USGS) since I was a kid. The USGS is a purely scientific agency with no regulatory authority that studies, geography, geology, and hydrology of the US, and publishes the well-known “topo maps” used by everyone from casual hikers to state and national planning offices.

One of the most significant areas of research in recent years for this agency has been the effect of Hydraulic Fracturing (or, more simply, “Fracking”). In spite of a “gag order” thrown up as an obstacle to the scientists' work in 2006 under President George W. Bush, the agency has finally weighed in on the public debate about fracking. A new USGS Abstract presented this week at a meeting of the Seismological Society of America concluded that since 2001, the average number of 3.0-or-greater earthquakes each year in the US has spiked significantly, resulting in a six-fold increase in 2011 over 20th century levels…and that these earthquakes are “almost certainly” man-made, the result of fracking.

Hydraulic Fracturing is the widening of fractures in underground layers of rock caused by the high-pressure injection of chemicals with water. This process is used to release petroleum, natural gas (including shale gas, tight gas and coal seam gas), or other substances for extraction by petrochemical companies. High-volume hydraulic fracturing can force as much as 2 to 3 million gallons of fluid per well. It is a growing method of energy extraction, as it is estimated by the International Energy Agency that the global use of natural gas will rise by more than 50% by 2035, and energy companies around the world scramble to locate gas in geological formations conducive to fracking.

Scientists first tied the disposal of resource-extraction wastewater with setting off earthquakes in Colorado more than 50 years ago. Wastewater injections from 1962 to 1966 at the Rocky Mountain Arsenal well near Denve were found to have triggered earthquakes, as the removal of huge volumes of oil, gas and water significantly changed underground pressures and stresses in the rock.

USGS scientists report that from 1970 until 2000, the middle of the country averaged 21 quakes In 2009 this jumped to 50, and then in 2011 it jumped again to 134 in 2011, occurring precisely in the locations where hundreds of fracking operations were taking place.

“In preliminary findings, our scientists cite a series of examples for which an uptick in seismic activity is observed in areas where the disposal of wastewater through deep-well injection increased significantly. These areas tend to be in the middle of the country – mostly in Colorado, Texas, Arkansas, Oklahoma and Ohio,” David Hayes, deputy secretary of the U.S. Department of Interior (which oversees the USGS), wrote that these quakes were big enough to be felt by a great number of people.

The characteristially guarded laguage reflects the fact that in December 2006, the Bush Administration announced a revision in rules for USGS publications, requiring that USGS leadership and communications staff be notified "of findings or data that may be especially newsworthy, have an impact on government policy, or contradict previous public understanding to ensure that proper officials are notified and that communication strategies are developed.”

In other words, scientists were told to submit their findings to political appointees who could sanitize and censor reports that might harm the energy industry. The release of the Abstract this week, then, is even more remarkable given those restrictions.
It was perhaps precipitated by an independent report issued by seismologists at Columbia University, who also concluded that a series of earthquakes that hit the Youngstown, Ohio area throughout 2011 (including a magnitude 4.0 quake on New Year's Eve)were linked to a hydraulic fracking disposal well. High-volume fracking has also been suspected in a string of earthquakes and massive fish and bird kills in Arkansas last year.

In addition to the problems associated with making severe changes to subsurface pressures, detractors have identified other environmental impacts of fracking, including contamination of ground water, and the migration of gases and hydraulic fracturing chemicals to the surface with their concurrent health effects. In 2010, “Gasland,” a film directed by Josh Fox, won the award for Best US Documentary Feature at the Sundance Film Festival in 2010.

A trailer from that documentary appears below, including a clip showing flammable gas coming out of a residential sink faucet:





Published USGS ABstract (with required sanitized language):

Are Seismicity Rate Changes in the Midcontinent Natural or Manmade?

ELLSWORTH, W. L., US Geological Survey, Menlo Park, CA, ; HICKMAN, S. H., US Geological Survey, Menlo Park, CA, ; LLEONS, A. L., US Geological Survey, Menlo Park, CA, ; MCGARR, A., US Geological Survey, Menlo Park, CA, ; MICHAEL, A. J., US Geological Survey, Menlo Park, CA, ; RUBINSTEIN, J. L., US Geological Survey, Menlo Park, CA,

A remarkable increase in the rate of M 3 and greater earthquakes is currently in progress in the US midcontinent. The average number of M >= 3 earthquakes/year increased starting in 2001, culminating in a six-fold increase over 20th century levels in 2011. Is this increase natural or manmade? To address this question, we take a regional approach to explore changes in the rate of earthquake occurrence in the midcontinent (defined here as 85° to 108° West, 25° to 50° North) using the USGS Preliminary Determination of Epicenters and National Seismic Hazard Map catalogs. These catalogs appear to be complete for M >= 3 since 1970. From 1970 through 2000, the rate of M >= 3 events averaged 21 +- 7.6/year in the entire region. This rate increased to 29 +- 3.5 from 2001 through 2008. In 2009, 2010 and 2011, 50, 87 and 134 events occurred, respectively. The modest increase that began in 2001 is due to increased seismicity in the coal bed methane field of the Raton Basin along the Colorado-New Mexico border west of Trinidad, CO. 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. Horton, et al. (2012) provided strong evidence linking the Guy, AR activity to deep waste water injection wells. In Oklahoma, the rate of M >= 3 events abruptly increased in 2009 from 1.2/year in the previous half-century to over 25/year. This rate increase is exclusive of the November 2011 M 5.6 earthquake and its aftershocks. A naturally-occurring rate change of this magnitude is unprecedented outside of volcanic settings or in the absence of a main shock, of which there were neither in this region. While the seismicity rate changes described here are almost certainly manmade, it remains to be determined how they are related to either changes in extraction methodologies or the rate of oil and gas production.

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