Earthquakes Hit Dallas/Ft. Worth Area
Published: Monday, November 5, 2012
Updated: Tuesday, November 20, 2012 17:11
Residents living near the Dallas-Fort Worth may have noticed the ground has become shakier in the last few years.
Around 10 p.m. on Oct. 16, a 2.7 magnitude earthquake struck near the town of Midlothian, Texas, according to the United States Geological Survey. It was yet another earthquake in an area that until a few years ago had been seismically silent.
“I heard thunder and thought it was just a storm coming in. I never would have thought it was an earthquake because the floor didn’t move,” SMU senior Robin Brock, who lives in Dallas, said.
Unlike major earthquakes that cause a lot of damage, the Texas earthquakes didn’t make national news because there wasn’t a significant amount of damage done.
The earthquakes have become ammo for opponents of the natural gas drilling procedure known as fracking because of suspicion the earthquakes have been caused by the drilling.
Others say the earthquakes are caused by natural events on the large existing fault system that lies under Texas.
The Dallas/Fort Worth area, which isn’t normally prone to repeated earthquakes, has experienced several earthquakes in recent years. On Sept. 26, 2012 an earthquake hit a few miles southeast of the Dallas-Fort Worth International Airport. On Sept. 30, 2012 another earthquake hit southeast of Las Colinas Country Club.
“Although the recent earthquakes are small, its important we try to understand them in more detail and try to understand the process. We owe it to our community,” said Seismologist and Southern Methodist University professor, Brian Stump.
Fracking, a drilling process that uses a mixture of water, sand and chemicals to fracture rock formations deep underground and extract oil and gas, began near the Dallas-Fort Worth airport in 2007.
The rapid expanse of fracking has also led to an increase in the number of wells required to dispose of the water used during the drilling process. Once that wastewater comes back up the well, it has to be disposed of, so drillers inject it into deep wells underground, as deep as 13,000 feet below the surface.
Many scientists believe that the wells used to dispose of fracking wastewater are responsible for the repetitive and recent earthquakes.
Oliver Boyd, a USGS seismologist and a professor of geophysics at the University of Memphis, was quoted in an article on the Huffington Post website that, “links between wastewater injection and seismic activity are plausible.”
Disposal and injection wells are permitted and inspected by the Railroad Commission of Texas, which oversees oil and gas drilling in the state.
The Railroad Commission of Texas stated on its website, “at this time has no data that links hydraulic fracturing activities to earthquakes.”
Other experts also agree that there is little connection between gas drilling and the recent earthquakes in North Texas.
“Fracking itself doesn’t cause earthquake,” said Stump.
Stump said it is important to understand the role of fluids, whether it is wastewater in gas production, carbon dioxide in fluid form, or any kind of wastewater injection process. If fluids are disposed of in a nearby fault for instance an earthquake may be generated.
In order to understand why earthquakes occur it is necessary to understand fault lines and not blame the oil and gas industry for being the only cause.
There are small faults everywhere, even in none tectonic areas of the US; the fluids may allow a resisting stress on the faults and therefore cause frictional change. It’s important to learn how to properly dispose of fluids because if fluids are disposed of by a nearby fault an earthquake may be generated
Stump said some people have made the linkage of earthquakes to fracking because of the fluids that are injected during the process, but later have to be disposed. It’s important to distinguish the issue is the disposal of larger volumes of fluid. Beyond the question of oil and gas…it’s fluids in general.
“Wherever there are large disposals of fluids is the problem that exists,” said Stump.