New research from the University of Texas at Austin suggests that fracking may have triggered one of the largest earthquakes ever recorded in East Texas. The quake struck the small town of Timpson, located about 30 miles northeast of Nacogdoches, on May 17, 2012. It was reported to have been felt as far as Shreveport, La.
Measuring in at a 4.8 magnitude, the earthquake caused minor property damage including broken windows and a dismantled chimney. Only one injury was reported: an elderly woman who was shook from her bed and suffered a cut on her arm.
Scientists from the University of Texas published their results in the Journal of Geophysical Research: Solid Earth, detailing the increasingly blatant correlation between wastewater disposal wells, drilling and earthquakes.
Wastewater injection wells linked to Texas quakes
Deep injection wells or brine disposal wells are used to dispose of toxic fluids left over from the fracking process, which involves the high-pressure injection of millions of gallons of water mixed with chemical additives into rock formations deep underground, making it possible to extract previously unreachable oil and gas reserves.
Industry spokespeople have insisted that fracking is harmless despite a lack of research demonstrating its safety on human health and the environment. Mounting research suggests the contrary, however.
Released to the public on Wednesday, the peer-reviewed study states that it’s “plausible” deep injection wells filled with oil and gas waste “triggered a series of temblors” near Timpson four years ago, according to the Texas Tribune.
Researchers found that an “injection-induced fault slip is plausible within the range of selected model input parameters, with slip favored by low reservoir permeability, low fault permeability, and a favorable orientation of the fault relative to the in situ stress state.”
The “most favorable conditions for fault slip” occurs about “7 months after the start of injection,” researchers concluded.
Slipping faults or fractures can trigger earthquakes. The high-pressured injection of chemical-laden fracking fluids may relieve pressure in some faults, thus causing them to slip, The Texas Tribune explains.
‘Fluid injection triggered Timpson quake’
This latest study builds on another report published in 2014, which identified two Class II injection disposal wells located within three kilometers “of the linear trend of aftershock activity” near Timpson.
The study found that fracking fluids were injected at 1.9 km in depth between August 2006 and February 2007 “with injection rates averaging” between 4 and 11 million gallons per month.
“Several observations support the hypothesis that fluid injection triggered the Timpson sequence: well-located epicenters are situated near a mapped basement fault and near high-volume injection wells, focal depths are at or below the depths of injection, and the earliest preshock (April 2008) occurred after the onset of injection in 2006,” researchers concluded.
Texas now high-risk state for earthquakes
Home to thousands of fracking wastewater wells, Texas has become the third most-at-risk state for man-made quakes, according to the U.S. Geological Survey. That places the Lone Star State behind only Oklahoma and Kansas.
The increasing number of Texas quakes, occurring mostly in the state’s northern region, has prompted lawmakers to allocate $4.5 million to monitor seismic activity.
“The earthquakes have created political challenges for the Texas Railroad Commission, which oversees the powerful oil and gas industry. In the past two years, the agency has added a staff seismologist and passed regulations requiring disposal well operators to submit more geographical information,” the Tribune reported.
“But the agency has refused to publically acknowledge the decades of research suggesting a link between human activity and earthquakes, saying the jury is still out.”
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