U.S. Geological Survey Calls Oklahoma Quake the Largest “Human-Induced” Earthquake on Record

Monday, March 10, 2014
Earthquake damage at St. Gregory's University in Shawnee, Oklahoma November 6, 2011 (photo: Sue Ogrocki, AP)

A study by the U.S. Geological Survey (USGS) associates a 5.7-magnitude earthquake in Oklahoma—the most powerful in the state’s history—with the practice of injecting wastewater from fracking into the earth’s crust.


The quake occurred on November 6, 2011, near Prague, Oklahoma. USGS scientists say it may have happened as a result of a 5.0-magnitude foreshock that happened on November 5 near some wastewater injection wells. The 5.0 quake increased stress at the site of the next day’s 5.7 quake.


“The observation that a human-induced earthquake can trigger a cascade of earthquakes, including a larger one, has important implications for reducing the seismic risk from wastewater injection,” said USGS seismologist and co-author of the study Elizabeth Cochran.


In the process of hydraulic fracturing, or fracking, water and chemicals are pumped into the Earth to force out deposits of oil and gas. The waste chemicals are then injected back into disposal wells. This practice is what researchers believe caused the quakes.  Moderate-sized earthquakes such as those in Oklahoma have been increasing in number in areas in the central United States near fracking sites.


“Even if wastewater injection only directly affects a low-hazard fault, those smaller events could trigger an event on a larger fault nearby,” Cochran told Live Science.


The USGS study isn’t the first to link earthquakes to wastewater disposal. In 2013, University of Oklahoma professor Katie Keranen found evidence linking the wells to an increase in seismic activity.


Other states have seen similar increases in earthquakes near injection sites. An area near an Ohio injection site experienced nine seismic events in eight months in 2011.

-Steve Straehley


To Learn More:

2011 Oklahoma Induced Earthquake May Have Triggered Larger Quake (U.S. Geological Survey)

Wastewater Injection Triggered Oklahoma's Earthquake Cascade (by Becky Oskin, Live Science)

Oklahoma's Largest Quake in Decades Buckles Highway; Rattles Residents (CNN)

Fracking Suspected in Rash of Earthquakes in Unlikely Places (by Noel Brinkerhoff and David Wallechinsky, AllGov)

Study Suggests Oklahoma Earthquakes Due to Oil Drilling Waste Disposal (by Noel Brinkerhoff, AllGov)



nuffalready 2 years ago
I side with Raul. Big government devotees jump all over this stuff, tossing 'conclusory statements' like granades toward the misguided green community. Big gov types at the USGS (especially at the EPA) toss bombs before they have a half a clue
justaxn 2 years ago
See C. Nicholson and R. Wesson, 1990, Earthquake hazard associated with deep well injection: USGS Bulletin 1951, 74 pages at http://pubs.usgs.gov/bul/1951/report.pdf and the 5 full pages of scientific references there. This topic has been fully researched since at least 1962. The physics are clear: inject too much too fast and you cause earthquakes. Move beyond your deep suspicion and read the literature.
Raul 2 years ago
In every article I've read on this (three so far)all I see is the bare allegation. Nowhere have I seen anything about this study, how it was done, etc., and nothing at all about what the causal mechanics are supposed to be. So one is left to either accept at face value what this darling of the leftists in DC, USGS seismologist says or one must reject it as unsupported by anything more than the bare allegation. When I read reporting such as this I hold the conclusory statements in deep suspicion.

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