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Fracking’s Newest Hazard: Earthquakes

By Guest Author: Paul Batistelli

For more than a decade Americans have been taking advantage of the vast natural gas resources found trapped beneath the earth’s surface in shale rock formations. The process to harness these resources, called fracking, is a controversial issue, with economists and environmentalists constantly butting heads. But the latest reports of earthquakes near shale formations in Texas and Arkansas might make everyone pause with concern.

Between 2010 and 2011 the town of Greenbrier, Arkansas, experienced more than 1,000 earthquakes—an unusual occurrence for the small town. Most of the quakes were small, the largest having a moderate magnitude of 4.7 on the Richter scale. The worst earthquakes are considered an 8 or above and can destroy communities. Though Greenbrier was free from severely damaging earthquakes, the sheer volume of them is alarming.

Seismologists at the U.S. Geological Survey investigated the issue, siting fracking wastewater disposal as the cause that triggered the quakes. As a result, the Arkansas Oil and

Gas Commission ordered several fracking wells to shut down. In addition, the findings prompted several residents of the city to file lawsuits against the area’s oil companies: Chesapeake Operating Inc., BHP Billiton and Clarita Operating LLC.
On August 28, five of these Arkansas homeowners settled their lawsuits for an undisclosed amount with Chesapeake Operating and BHP Billiton. Clarita Operating LLC was dropped from all lawsuits in 2011 after it filed for bankruptcy.

Despite these settlements, there are still several lawsuits that remain active in federal court. If any of the lawsuits make it to trial and the plaintiff wins, it could open up further litigation in other forms of drilling. Like fracking, geothermal energy production, oil and gas drilling all inject wastewater into wells.

Earthquakes in Texas

 

Fracking is also shaking things up in Texas. Between 2009 and 2011 the state had 62 earthquakes near the Eagle Ford Shale formation, according to a study by the journal of Earth and Planetary Science. The study looked at all the earthquakes in the two-year period and determined that in most cases the quakes were caused by fluid extraction instead of wastewater injection, contrary to the findings in Arkansas. In fact, the study shows the area’s biggest quake, with a 4.8 magnitude, was actually caused by pulling oil out of the ground.

New wells in the Eagle Ford Shale allow for the extraction of 600,000 barrels of oil each day. Though the true reason for extraction earthquakes isn’t known, it’s possible that the high amount of oil removal could be disturbing rocks that have settled along fault lines, causing minor earthquakes.

The results of the survey were not what scientists expected. In fact, an earlier study from the journal of Earth and Planetary Science drew a different conclusion in Texas’ Barnett Shale formation.  Here, the study found that earthquakes could be attributed to wastewater injection at fracking sites.  The authors believe the extent of drilling may be the root cause of the different findings. Eagle Ford has been subject to drilling since the 1970s whereas Barnett has experienced fracking since only 2004.

Paul Batistelli freelances in the energy field for the promotion of a greener society and energy means. He works to raise awareness on ecological issues, energy dependency, and reducing carbon footprints. He currently resides in Dallas, TX with his lab, Copeland.

Earthquake icon image via Shutterstock.

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