Study links fracking wastewater to massive 2011 Oklahoma quake
from Raw Story:
____ A study published Tuesday in the scientific journal Geology links the magnitude 5.6 earthquake that hit Oklahoma in November 2011 to natural gas drilling operations nearby that were using an extraction technique called fracking, which requires massive quantities of wastewater be injected into underground reservoirs . . .
Researchers at the University of Oklahoma and Columbia University noticed that the quake was one of five greater than magnitude 5.0 that occurred in the continental interior of the U.S. in 2011. Studying the aftershocks of the Oklahoma quake, they discovered that the rupture plane of the quake, or the site where the tension built up and then violently shifted, was within 200 meters of fracking injection sites and nearly one meter from the surface.
Interestingly, the study’s findings show that while most seismic activity linked to newly installed fracking wells is minor, tension between fault planes can build for years, resulting in unexpected interactions with wastewater sites.
In this case, researchers said 18 years worth of fluid injection in sealed oil wells “lowered effective stress on reservoir-bounding faults,” causing several fault planes to give way in sequence after the initial quake hit, which is why the quake was so substantial.
read more: http://www.rawstory.com/rs/2013/03/27/study-links-fracking-wastewater-to-massive-2011-oklahoma-quake/?utm_source=twitterfeed&utm_medium=twitter
related:
BBC: Oklahoma earthquake linked to oil extraction wastewater
http://www.bbc.co.uk/news/science-environment-21952428