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Wed June 20, 2012
Man-Made Earthquakes Get Geologists' Attention
Originally published on Wed June 20, 2012 8:16 am
RENEE MONTAGNE, HOST:
Geologists have noticed a remarkable increase in the number of small earthquakes in the U.S. They suspect the cause to be waste water wells. That's where polluted water from industrial processes is pumped deep underground. Now, none of the quakes have caused serious damage. But as NPR's Christopher Joyce reports, the seismic spike casts doubt on plans to bury underground all sorts of unwanted stuff.
CHRISTOPHER JOYCE, BYLINE: They're called induced earthquakes, man-made. They used to be rare. Pretty much only geologists paid attention to them. They suspected that waste water wells were one cause. Geologist Bill Ellsworth is with the U.S. Geological Survey.
BILL ELLSWORTH: Any time we're perturbing the state of stress underground, that has the possibility of causing earthquakes.
JOYCE: Underground rocks are filled with cracks - fault-lines. If you pump water near one, it's like lubricating a sliding door that's stuck. The rocks are going to slip more easily.
Now there's a new study by the National Research Council in Washington, D.C. that confirms that waste wells are causing quakes and that the oil and gas boom right now has a lot to do with that. They use lots of water to get at oil and gas underground.
MURRAY HITZMAN: So there's just more types of water to dispose of.
JOYCE: That's geologist Murray Hitzman of the Colorado School of Mines. He ran the NRC study. He says expect more quakes.
HITZMAN: We're going to cause more events as we drill more wells. I think there's not much question about that. But we understand what's happening pretty well and I think we can get in place, without too much problem, protocols and systems so that we can deal with it in a very reasonable way.
JOYCE: Such as taking a much closer look at where natural faults are underground before drilling a waste well. But it's more than water that people want to bury. Carbon dioxide, for example. Why CO2? Well, it's the main climate-warming gas, mostly from coal-fired power plants. The federal government is spending millions figuring out how to keep it out of the air, like burying it. But geologist Mark Zoback and his colleagues at Stanford University say let's not rush into this.
MARK ZOBACK: The real problem is the scale. You're talking about injecting a volume of fluid, oh, on the order of about 27 billion barrels a year.
JOYCE: Once injected, the CO2 acts like a fluid, lubricating the fault. And 27 billion barrels dwarfs the amount of waste water the oil and gas industry is producing.
ZOBACK: So it's an extremely large, costly, and we believe high risk endeavor.
JOYCE: Writing in the Proceedings of the National Academy of Sciences, Zoback says even a small quake could release the CO2 back into the atmosphere, where it would contribute to global warming.
ZOBACK: A leak need not threaten the public, but a leak would, you know, obviate the whole purpose of the endeavor. And you know, we're talking about spending literally trillions of dollars over, say, half a century to do this.
JOYCE: Zoback and Hitzman took their concerns to Congress, which is weighing new laws to develop so-called carbon capture and storage underground. Democratic Senator Jeff Bingaman of New Mexico was encouraged by the NRC report, which suggests that geologists should be able to avoid quake-prone areas. Hitzman wasn't so sure.
SENATOR JEFF BINGAMAN: As long as we stay away from the known faults that are naturally there, we pretty much deal with that problem.
HITZMAN: Right, but what happens is there are faults we don't know about. And that's where we've had the problems.
JOYCE: Geological Survey scientists are writing guidelines for locating faults near waste wells. But as for who finds them - well, the USGS says they don't have the money or the staff.
Christopher Joyce, NPR News. Transcript provided by NPR, Copyright NPR.