Another North Texas quake raises more questions about drilling

By Bill Hanna

billhanna@star-telegram.com

After 10 earthquakes in the past month, the questions about what's causing the ground to shake in Johnson County refuse to go away.

The latest quake, magnitude 2.7, was measured Friday morning between Godley and Pecan Plantation, but few noticed. Both the Johnson and Hood County sheriff's departments said there were no reports of damages or injuries.

Former Johnson County Commissioner R.C. McFall's home isn't far from the epicenter, but he said his wife, who was home, didn't feel a thing.

"She saw it on the dang TV and then called me and said we had another quake," McFall said.

The earthquakes have become so commonplace that most residents take them in stride.

"We talked about it at the coffee shop this morning, but nobody felt it," Johnson County Judge Roger Harmon said. "I think they've become so prevalent that everyone is like, 'Well there goes another one.'"

Though seismologists have said the possibility of a major quake in North Texas is minuscule, Harmon said county officials can't help but wonder whether it is possible.

"What if, instead of 2.6, it was 6.2?" Harmon said. "That would be devastating. We really don't have any plan for dealing with an earthquake. We do for every other natural disaster. And we really don't have an answer for what's causing them."

Harmon said many residents are asking whether the wastewater disposal wells associated with the surge in natural gas activity have anything to do with it.

Last month, a report by the National Research Council found that hydraulic fracturing poses a small chance for causing quakes but said there are higher risks from wastewater injection wells, where the fluid from the drilling and production process is injected back into the ground.

Ken Morgan, associate dean and director of the TCU Energy Institute, said most of the attention is focused on wastewater wells because that process occurs at the same depth as the earthquakes. Hydraulic fracturing (fracking) takes place at a much shallower depth.

"We have to take into account that these disposal wells are going down to the depths where these quakes are occurring," Morgan said. "They're relatively small but still unsettling."

Research suggests that reducing that flow rate of wastewater into the ground could lessen the frequency of quakes, Morgan said, and he expects the industry to look more closely at this issue.

The increased look at wastewater wells was a focus this year in Fort Worth as the City Council debated whether to lift a moratorium on those wells inside city limits. Ultimately, council members voted in April to ban the wells.

"I think the City Council was very wise to prohibit them in Fort Worth," said Libby Willis, president of the Fort Worth League of Neighborhoods.

She had said research nationwide raises questions about links between quakes and disposal wells.

The recent round of Johnson County earthquakes, she said, demonstrates that there are still too many unknowns about the process.

There are two disposal wells in Fort Worth -- a pilot project in the Brentwood Stair area and one that was recently annexed on the far north side.

But Ed Ireland, director of the Barnett Shale Energy Education Council, said the focus should be strictly on disposal wells at or near fault lines, noting that no seismic activity has been recorded near most of the 50,000 disposal wells statewide.

Ireland said he doesn't believe that research has found conclusive links between disposal wells and quakes but said the issue does have the industry's full attention.

"I think there's a lot of interest, especially for those who use or own disposal wells," Ireland said. "I think there is interest in understanding if there is any connection and if there are practices, for example, like reducing the rate of flow that could reduce any problems."

Bill Hanna, 817-390-7698

Twitter: @fwhanna

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