Researchers have found that the disposing of fracking wastewater might be associated with an increase in earthquakes.
Fracking drilling for natural gas involves horizontally injecting tons of silica sand, a massive mix of more than 600 chemicals, and water at least one mile underground via a drill into a concrete well that extends to a bed of shale rock deep beneath the earth’s surface. When this combination reaches the rock, it is blasted apart and natural gas is released and supposed to be returned to the surface and captured; most of the water remains underground. Industry has injected more than 30 trillion gallons of toxic fracking wastewater deep into the earth.
Now, researchers from Columbia University and the University of Oklahoma have found what they describe as a “profound” increase in the number of earthquakes at three different sites in which fracking wastewater was injected into the ground, said the study’s lead author, Nicholas van der Elst, a scientist at Columbia’s Lamont-Doherty Earth Observatory in Palisades, New York, according to Bloomberg News. van der Elst’s article on the research appears in Science.
The researchers found that fracking wastewater disposal might impact fault zones, making them more prone to earthquakes. As subsurface rocks become saturated with fracking fluids, area fault lines, in turn, may become less stable, van der Elst said, according to Bloomberg News. “This study helps show the link between the pumping and the earthquakes,” van der Elst said in an interview.
In fact, the report indicated that “significant seismic activity” taking place in other locations on earth—even as far away as on other continents—might “induce” an earthquake in a fracking injection zone days, even hours, following injection. “Seismic waves from the distant earthquake can squeeze the rock like a sponge,” van der Elst told Bloomberg News.
The team researched fracking injection sites in Oklahoma, Texas, and Colorado, recording “hundreds” of earthquakes in one year “where you might have expected a dozen,” they said, according to Bloomberg News. Injecting fracking for permanent underground storage might significantly impact fault lines, even more so than the fracking process itself, which is significantly invasive. The report revealed that more than half of the U.S. earthquakes recorded with magnitudes of 4.5 and greater in the past 10 years, “occurred in regions of potential injection-induced seismicity.”
We have long written about the connection between fracking activities and increased seismic activity and earthquakes. For example, a 2011 earthquake that was widely felt in Oklahoma and considered “unusual” was likely caused by drilling activities and was not a natural event. That 5.6-magnitude quake was believed linked to oil drilling waste that was pushed too deeply below ground, according to a scientific team of university academics and federal staff, said The Associated Press (AP).
Geophysicists at the University of Oklahoma, Columbia University and the USGS say that, on November 5, a smaller quake occurred in an old oil well that was used to get rid of wastewater. That well sits along a fault line, said the AP. According to the groups, the smaller quake set off the larger quake, as well as a third, smaller aftershock. The tremors occurred at the wastewater storage location and there was an increase in well pressure, which all point to injections causing the larger quake, the groups said. That area of Oklahoma was the site of oil drilling as far back as the 1950s; wastewater had been pumped into that area’s disposal wells since 1993.
Fracking might also have been the culprit in three Dallas area earthquakes, according to a geophysicist and earthquake expert. Also, in the last few years, especially, there has been a rise in seismic activity in areas not typically the site of earthquakes.
Underground injection wells for disposing fracking wastewater have been used since the 1960s but only recently has more and more fluid been used in the process. This has created a massive amount of wastewater and a need for more disposal sites. Prior studies suggest the briny, salty nature of the drilling fluid causes lubrication of underground rock. If the site of the underground well is near a natural fault line, the wastewater may eventually cause the rocks to move.
“While the earthquakes are natural, relieving natural stresses, you’re making them happen in your lifetime rather than somebody else’s lifetime,” van der Elst told Bloomberg News. “They can’t just be dismissed.”