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Tuesday, March 18, 2014

Is Fracking Causing East Texas Earthquakes?

The water tower in Timpson wasn't build to withstand earthquakes. "After 4.0 [on the Richter scale], we get pretty nervous," says Debra Smith, the mayor. "We have buildings in town that are over a hundred years old." (Terrence Henry/StateImpact Texas)

The water tower in Timpson wasn’t build to withstand earthquakes. “After 4.0 [on the Richter scale], we get pretty nervous,” says Debra Smith, the mayor. “We have buildings in town that are over a hundred years old.” (Terrence Henry/StateImpact Texas)

Earthquakes have been rocking Texas recently. In the last several years since a fracking boom began, the number of recorded earthquakes has increased tenfold.

Scientists in Texas and other states are studying whether wastewater sent to disposal wells are the culprits. It’s a question that has been around for years, but there are no simple answers.

Now, scientists at the University of Texas at Austin have connected a relatively large earthquake in East Texas to disposal wells.

From the Here & Now Contributors Network, Terrence Henry of StateImpact Texas reports.




Well here in the Los Angeles area, many of us were woken up by a 4.4 magnitude earthquake yesterday morning, the biggest quake to hit Southern California since 2008. But L.A. is not the only place that is shaking. Parts of the country that up until recently only rarely felt earthquakes are now seeing them on a near daily basis, and some of them are likely manmade, linked to the process of oil and gas drilling.

From the HERE AND NOW contributors network, Terrence Henry of KUT in Austin reports.

TERRENCE HENRY: Ever wonder what it feels like to be woken up in the middle of the night by an earthquake?

PAULA MULLENS: Freaky, it really is, like screaming, your heart's racing, and you just - it's bad.

HENRY: You might expect to hear something like that out of California, but Paula Mullens(ph) lives in the East Texas town of Timpson. The quakes here have been some of the strongest in the state. Chimneys have fallen down, TVs knocked off the wall. They've even rearranged furniture, says Debra Smith, Timpson's mayor.

MAYOR DEBRA SMITH: My four poster bed sits on a hardwood floor, and it was moving around with me in it. That's not pleasant.

HENRY: Many of the earthquakes across Texas in the last few years have been relatively small, but Timpson has seen quakes as strong as 4.8 on the Richter scale.

SMITH: After four, it's not fun. After four, we get pretty nervous. We have buildings up in town that are over 100 years old.

LARRY BURNS: You know, if the quakes get much over a five, then yeah, we suspect we will have some damage. It could be anywhere from broken lines, broken mains to water tower in the ground.

HENRY: Larry Burns is the emergency coordinator for Timpson. He's showing us around town. Timpson's water tower is about two decades old and sits next to the Union Pacific rail line. That goes right through the middle of town.

BURNS: The elevated water tower was not built to earthquake standards at all. I mean, we just didn't live in an area where, you know, that happened. So they didn't include that.

HENRY: So what's causing the quakes here and in other parts of Texas? Scientists are studying whether wastewater from oil and gas drilling is the culprit. In Timpson, that wastewater is trucked to one of the area's disposal wells, like this one just a few miles outside of town. Jacob Shelton(ph) is an operator for Gator Services.

JACOB SHELTON: This is our disposal pit right here. There's a rack up there where the trucks pull up and just unload.

HENRY: Gator Services runs this disposal well, and on a busy day, several tanker trucks will pull up and unload wastewater from fracking and drilling.

SHELTON: The water comes into this little pit right here, and we have a transfer pump that actually puts that water back down the hole over there toward the well head.

HENRY: The wastewater is then sent into a well that goes nearly two miles underground, and that's the point where a small operation like this could turn out to be causing big tremors that can be felt miles away. But to understand how, let's take a little trip to Austin.

CLIFF FROHLICH: Yeah, this is Cliff Frohlich. I'm the associate director and senior research scientist at the Institute for Geophysics at the University of Texas at Austin. The last couple years, I've been interested in earthquakes that might be caused by fluid injection of fluids that are for waste disposal.

HENRY: Frohlich's workspace isn't full of test tubes, bubbling beakers and sparkly rocks. Instead, it's a world of paper: maps, spreadsheets, books - oh, and some bowling balls, appropriately named...

FROHLICH: Quake and The Aftershock and The Tremor. A seismologist has to try these things out if he's a bowler. It's a seismoscope. If a magnitude 4.3 earthquake happens here, those balls will roll off and bounce on the ground. Well, my desk, you notice they're not right over my desk.

HENRY: Frohlich says the science behind the phenomenon of manmade quakes is nothing new. We've known about manmade quakes for years.

FROHLICH: In the earthquake research business, the idea that injection could cause earthquakes first came up in the 1960s. The Army in Denver had a disposal well.

HENRY: What you'll hear next is from a 1970 science series called "Understanding the Earth" hosted by a geologist named David Pearson.


DAVID PEARSON: Denver was previously a rather stable city with little in the way of quakes, but suddenly it was hit between 1962 and 1965 by about 700 quakes. They came as something of a shock to many of the Denver residents.

FROHLICH: And they never said what they were disposing of, but most people think it was stuff related to the production of nerve gas. You know, what do you do with that stuff? You don't dump it in the creek. And so they were pumping it back in the ground.


PEARSON: It's about 150 million gallons of it down a three-mile-deep hole.

They got some earthquakes that caught people's and scientists' attention.


FROHLICH: This fluid had lubricated a fault, which ran right through the position of the well.

HENRY: Frohlich has a simple way of explaining the complex geology at work here.

FROHLICH: I call it the air hockey model. If you put the puck on there, but the air is not on, the puck will just sit there because of friction. As soon as you turn on the air, the puck slides.

HENRY: And that's not all that different from what can happen with a disposal well.

FROHLICH: The same thing a fault. I mean faults, there's stress everywhere. Most faults are pressed together by the weight of the rock. They're stuck. If you force fluids in there, you still have the stress that wants to make them slip.

HENRY: When those faults slip due to the pressure and liquids, earthquakes can happen. So that's how a disposal well can cause tremors. But how do you determine if it's behind a particular one, like the ones in Texas. After all, the state's always had some earthquakes. But Texas has seen the number of recorded earthquakes increase by a factor of 10 since the drilling boon began several years ago. How do you determine if there's a relationship between the two?

FROHLICH: All you do is you assemble as much evidence as you can and just try to see how that evidence leads.

HENRY: For Frohlich and other researchers looking at Texas quakes, that means data, lots of it. For instance Frohlich and some other scientists noticed a swarm of quakes near Dallas-Fort Worth on Halloween in 2008.

FROHLICH: We found that the earthquakes were about the same depth as an injection well. They were within about a kilometer of an injection well for waste disposal. And they started six weeks after the injection started.

HENRY: It was just one of several peer-reviewed studies that have shown some disposal wells in certain areas can cause earthquakes, and it isn't just Texas. In Arkansas, Ohio and Oklahoma, studies have also linked disposal wells to quakes. Frohlich published a study in January that tied the largest of those Timpson quakes to disposal wells. And as for the ongoing earthquake swarm in North Texas, researchers say it could take years to get to the bottom of it.

And even then the answers won't be 100 percent black and white. Science rarely is. For HERE AND NOW, I'm Terrence Henry in Austin, Texas.

HOBSON: You're listening to HERE AND NOW. Transcript provided by NPR, Copyright NPR.

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