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Man-made earthquakesFeeling the impact of fracking

By Colleen Walsh

Published 19 June 2017

Fracking involves drilling holes deep into layers of subterranean shale and then pumping in millions of gallons of water, sand, and chemicals to release oil and natural gas trapped in the rock. In some shale formations, a large volume of toxic water comes up along with the hydrocarbons. The injection of the wastewater from the process back into the earth can trigger seismic activity, scientists say. According to the U.S. Energy Information Administration, there were approximately 26,000 hydraulically fractured wells for natural gas in the United States in 2000. By 2015, the number had grown to 300,000. Researchers are studying the link between fracking and earthquakes

He’s an unlikely seismological muse, but Davy Crockett inspired a Radcliffe fellow’s fascination with earthquakes.

In his autobiography, the legendary frontiersman described jumping over “earthquake cracks” in his home state of Tennessee while pursuing a bear one night in 1826. Conevery Bolton Valencius was struck by the reference.

“I thought, ‘What in the world is this about earthquakes?’” remembers Valencius, an environmental historian and Boston College professor. “How could it be that I got a Ph.D. in history and I study this part of the world and I don’t know much about this? So I started asking.”

Those questions led to The Lost History of the New Madrid Earthquakes, Valencius’ 2013 book about violent tremors that rocked the central Mississippi valley between December 1811 and March 1812. In the course of her research Valencius noticed online posts from people worried that hydraulic fracturing, or fracking, would “set off the New Madrid fault and crack the United States in two.” Again, she wanted answers.

Fracking involves drilling holes deep into layers of subterranean shale and then pumping in millions of gallons of water, sand, and chemicals to release oil and natural gas trapped in the rock. In some shale formations, a large volume of toxic water comes up along with the hydrocarbons. The injection of the wastewater from the process back into the earth can trigger seismic activity, scientists say.

According to the U.S. Energy Information Administration, there were approximately 26,000 hydraulically fractured wells for natural gas in the United States in 2000. By 2015, the number had grown to 300,000.

While at the Radcliffe Institute for Advanced Study Valencius has been working on a book that explores what’s known and what’s not about earthquakes caused by fracking’s deep-level wastewater injection wells. (She also found a co-author during her fellowship, connecting through Radcliffe colleagues with Anna Kuchment, a contributing editor for Scientific American and a staff writer for The Dallas Morning News, who has covered connections between fracking and the earthquakes for years.)

Studies conducted over the past decade have documented close correlations between wastewater injection wells and earthquakes, Valencius said. The findings indicate that the massive amounts of water pumped into the earth create intense pressures that can trigger a fault.