Another minor earthquake close to the Barnett Shale rumbled through north Texas this week.
The Ovilla earthquake’s magnitude registered as a 2.4 on the Richter scale. Although the United States Geological Survey (USGS) says that an earthquake with a magnitude of less than 3.5 isn’t typically noticeable, at least three people reported feeling the quake to the USGS web site.
Ovilla Fire Department Captain Brandon Kennedy said that he didn’t feel the earthquake, nor did he receive any calls about it. According to Kennedy, it was the first earthquake he’d even heard of in his hometown.
“I’ve never known of [an earthquake] since I’ve lived in Ovilla,” Kennedy said.
But Ovilla is on the eastern edge of the Barnett Shale, where oil and gas operators have been using hydraulic fracturing, or “fracking,” since the late 1990s. Fracking is a drilling process that injects millions of gallons of water, sand, and chemicals under high pressure into a well, cracking the rock to release oil and natural gas.
Research by Dr. Cliff Frohlich, a professor of geophysics at the University of Texas at Austin, has scientifically linked part of the drilling process to earthquakes, but not during fracking. Rather it’s the wastewater involved in drilling that is the likely culprit. His research shows that injecting wastewater from drilling into disposal wells can cause a fault to slip, resulting in an earthquake. The Texas Railroad Commission currently lists 29 disposal wells in Ellis County.
Although there has been a rash of these small quakes in the Barnett Shale over the past few years, the exact number couldn’t be verified because of the government shutdown.