Did Fracking Wastewater Disposal Cause East Texas’ Biggest Earthquake? - Pacific Standard

Did Fracking Wastewater Disposal Cause East Texas’ Biggest Earthquake?

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It would appear so, according to a new study. Yet the Texas agency tasked with regulating oil drillers has never publicly linked any earthquake to industry activity.

By Francie Diep

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A fracking site is situated in Texas. (Photo: Spencer Platt/Getty Images)

The largest-ever recorded earthquake in eastern Texas was caused by a common oil-drilling practice called wastewater or fluid injection, a new study finds.

Past research has come to a similar conclusion. Previously, another science team’s investigation found that the magnitude 4.8 quake, which struck the 1,200-person town of Timpson in 2012,was “possibly triggered by fluid injection.” Both studies are part of a growing body of evidence pointing to the fact that, over the past several years, fluid injection has caused earthquakes throughout oil-rich America. Yet certain oil companies and at least one state agency—the one in charge of monitoring frackers in Texas— don’t seem to agree.

Fluid injection is the practice of disposing of the toxic wastewater that fracking produces by pushing it into deep wells drilled into the Earth. Wherever all that wastewater is pumped in, it creates intense pressure. If the wastewater wells are located near a fault in the Earth, that pressure can reduce the frictional forces that hold faults steady, making the fault slip, triggering an earthquake.

Between 2009 and 2016, central and eastern states saw more than 2,300 earthquakes of magnitude 3 or higher.

It can be difficult to scientifically prove any specific earthquake was caused by a wastewater well and not by a fault slipping on its own, but geologists agree that wastewater injection is to blame for the recent uptick in earthquakes in normally quiescent states such as Oklahoma, Kansas, and Texas. Between 2009 and 2016, central and eastern states saw more than 2,300 earthquakes of magnitude 3 or higher. That’s nearly three times as many earthquakes of that size as hit those same states in the previous 39 years.

Most injection-triggered earthquakes aren’t severe enough to cause damage, but some do. Timpson’s big one broke windows and damaged a chimney, according to a local news station.

The new study demonstrates that the science exists for oil companies to better plan their injection wells to be less likely to cause bigger quakes, says Manoochehr Sirzaei, a geophysicist at Arizona State University who worked on the new study, which published today in the journal Science. “We’re going to have wastewater injection. It’s going to happen,” he says. “The solution is to customize the injection. You can come up with an injection strategy.”

Depending on the geology of the site where oil companies want to bury wastewater, they may cut their risks by injecting smaller volumes, or by more strategically locating wells. Sirzaei’s study found that there were four wastewater injection wells within a six-mile radius of the Timpson quake, but because of the structure of underlying rock where they were located, only two of the wells likely caused the tremblors.

The Texas Railroad Commission, the agency in charge of regulating oil drilling in the state, has never publicly acknowledged that wastewater injection caused Texan earthquakes, the Texas Tribune reports. Yet the commission’s actions sometimes make it seem as if it is indeed aware of a link. In a recent review, the federal Environmental Protection Agency praised the Texas Railroad Commission for laying down stricter rules aimed at reducing Earth shaking from wastewater injection wells — while indicating the EPA itself “believes there is a significant possibility that North Texas earthquake activity is associated with disposal wells,” contrary to the railroad commissioners’ claims.

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