MICHEL MARTIN, HOST:
An earthquake rattled northern Oklahoma early Saturday morning with a magnitude 5.6, one of the strongest in the state's history. So far no fatalities have been reported, but people felt the quake as far away as St. Louis, Mo., Dallas, Texas, and even Memphis, Tenn. Now, Oklahoma has experienced a number of earthquakes this year, some of which have been linked to the underground disposal of wastewater from oil and natural gas production. To find out more, we called Joe Wertz. He's a reporter with StateImpact Oklahoma, and he's covering this story. Hi, Joe.
JOE WERTZ: Hey, how are you doing?
MARTIN: Good. So you spent some time in Pawnee, Okla., about eight miles from the epicenter. What did you see there?
WERTZ: I saw and talked to a lot of worried residents, people with a lot of damage inside and outside their homes, brick facades, sheering off buildings in downtown Pawnee. Inside people's homes lots of things broken - shelves broken on walls, cracked chimneys. I talked to one resident - Dave Denney. He lives in a trailer home, and his whole home had shifted off the foundation and crumbled some of the supporting blocks underneath.
DAVE DENNEY: Yeah, I've got busted blocks underneath. I wouldn't know how far, but it did bust my line. That's what I seen right there, the sewer line coming out.
WERTZ: Oh, wow.
DENNEY: That's where I seen that something happened more than what I thought happened.
WERTZ: So they were out there trying to make emergency repairs to that sewer line, wrapping some tape around it, trying to get it - a makeshift sewer line working until they could get somebody out to make a permanent repair.
MARTIN: Now, this isn't the first large earthquake that we've seen in Oklahoma. There was a magnitude 5 quake back in February. And there was another one in 2011. Now, we talked to Daniel McNamara. He's a researcher at the U.S. Geological Survey. And he told us...
DANIEL MCNAMARA: A number of these earthquakes have been linked to oil and gas wastewater disposal. This one that occurred today - we can't say yet if it's directly related to wastewater injection, but it looks very similar to events that have been linked.
MARTIN: Now, Joe, you've reported on this a fair amount yourself. Can you tell us about the impact of oil and gas wastewater on quakes? And to be absolutely clear, we're not just talking about fracking here, correct?
WERTZ: Right. In Oklahoma, the wells produce a lot of water that comes up with the oil and gas, and you have to filter that often and do something with that toxic water. You pump it back underground. And that's what's thought to be causing most of the shaking. We're up to more than a dozen peer-reviewed scientific research papers that have made the connection. A chorus of scientists seem to think that's what's causing the shaking.
MARTIN: So I understand that government officials in Oklahoma have started to acknowledge the role of wastewater disposal in the recent earthquakes, but that's a bit of a complicated conversation there. So can you talk us through the politics of this?
WERTZ: Yeah, so when science first started coming out making these links between the oil and gas activity and the earthquakes, state officials in Oklahoma were reluctant to publicly acknowledge the science. It was really only last year that our state geological survey came out and formally, publicly acknowledged the link, and some number of months later that Governor Mary Fallin came out and publicly acknowledged the link.
MARTIN: Before we let you go, any sense of where public opinion is about this?
WERTZ: Yeah, well, people who are experiencing the shaking, they're worried, and they want it to stop. And I think, at least in my interviews with people, who have maybe expressed reluctance to connect the oil industry, at least initially, have come around because the scientific evidence has been so persistent and has really built.
MARTIN: That's Joe Wertz. He's an energy reporter for StateImpact Oklahoma. Joe, thank you.
WERTZ: Thank you. Transcript provided by NPR, Copyright NPR.