People in North Texas worry about tornadoes, not earthquakes. That's not the case in the small town of Cleburne, just south of Fort Worth. They've had six quakes so far this month.
Cleburne happens to sit on a huge, recently discovered natural gas deposit called Barnett Shale. There's been a lot of drilling, and some people wonder if that has triggered the earthquakes. Here, a four-story drilling rig can pop up in as little as a couple of days. In the past eight years, 2,000 gas wells have been drilled here.
While most of rural America slowly dies on the vine, Cleburne is building civic center additions and opening championship municipal golf courses across the street from lakefront McMansions.
The 18-hole Cleburne Municipal Golf Course was built in part with money that the city received from royalties from natural gas companies that built on city ground.
Nobody thought much about it when a small tremor shook the town in early June. It was 2.8 magnitude quake and was the first in town history. But then a couple of days later, another earthquake. Then another quake. Then another.
Natural gas recovery in the Barnett Shale involves drilling down several thousand feet and then drilling sideways thousands of feet more. Liquid is then pumped down the wells at very high pressures, which fractures the strata releasing the pockets of natural gas. Could this be causing little quakes?
The city itself is raking in millions of dollars in natural gas royalties — more than $9 million last year alone. That goes a long way in a town of 30,000. And hundreds of other property owners are getting anywhere from $300 to $400 to tens of thousands of dollars in the mail each month.
"Everybody has an opinion, and it largely depends on whether you have mailbox money," says Chester Nolan, Cleburne's city manager.
In order to feel any of the Cleburne quakes, you had to be in the right place at the right time.
"I have talked to a few customers who said they felt it slightly, but most have not felt it," says Jena Williams, who runs the Red Horse Antique Mall. Williams wants the city to try to find out if the tremors are a fluke of nature or man-made.
"If it's the drilling and they continue to drill, what's going to be the consequences?" she asks.
Matt Smith, reporter for the Cleburne Times Review, has been covering the story.
"A lot of people are thinking it's overblown, that these are minor events. I don't think anyone's overly concerned that I've talked to," he says.
Smith says even though there's not a scintilla of evidence about whether the quakes are natural or man-made, many in Cleburne have already made up their minds.
"People that lean right say this is natural; people that lean left say it's the drilling," Smith says.
The city leaders in Cleburne asked Brian Stump, seismologist with Southern Methodist University, to investigate. Stump is installing four seismometers around town, which will gather more detailed data. He's avoiding the politics of the situation.
"We're really focusing on the science issues, and then we'll let people judge for themselves," Stump says.
Could injection of fluids in the crust be responsible? Perhaps it's one of the fault lines that run from Austin to Oklahoma 3 miles down? The driller, Chesapeake Energy, says it'll cooperate with Stump.
One thing is certain: It's 102 degrees in the shade this week in the Lone Star State, and all that natural gas is being burned up as fast as it's brought up — powering air conditioning condensers as far as the eye can see.