SCOTT SIMON, HOST:
If any of the NATO leaders from this side of the Atlantic flew back over Iceland in their return flights and looked down, there's a chance they would have seen the active spouting Bardarbunga volcano. It's been spewing lava since last month - fire, ash and a few dauntless human beings.
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SIMON REDFERN: We're approaching the fissure eruption near Bardarbunga.
SIMON: This is audio recorded by scientists from Cambridge, who are just about as close to that rolling wave of lava as people can get without being too daft to be scientists.
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UNIDENTIFIED WOMAN: You should not go any closer than this, though.
SIMON: We spoke to one of the scientists, Simon Redfern. He's posted pictures and video on Twitter this week of the slow-moving lava.
REDFERN: When it's moving in this state, we can get up to about a yard from it. But it's very hot. It's at about 500 centigrade to 300 centigrade at the surface.
SIMON: That's over 900 degrees in this country - even hotter. Lava is hot. It can also be loud.
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UNIDENTIFIED WOMAN: You hear the noise?
REDFERN: Yeah.
SIMON: That sounds a bit like stepping on packing popcorn. Simon Redfern says the lava crackles as it moves.
REDFERN: Because actually, as the molten rock cools very rapidly it actually forms a glass. Then as it moves forward, that glass breaks and fractures and it crackles, just like breaking glass.
SIMON: Surveying volcanoes is risky and not only in the obvious ways you may think. Simon Redfern says that this week his team accidentally popped two tires on their SUV.
REDFERN: Potentially a dangerous situation because should the Bardarbunga volcano erupt, not only would it produce an ash cloud, it would melt the glacier that's above it as well and that would create a local flood. And so you would want to be able to get away.
SIMON: I'd say. Dr. Redfern says this volcano could still release an ash cloud that could blot out European airspace, like another Icelandic volcano did just four years ago. That might keep him from getting back to ivied Cambridge. But he says this past week seeing the volcano up close has been...
REDFERN: Actually, in this case, the adjective that best described the experience was awesome, which I know many in North America use the regular word, but in this case, I mean it was an experience that was full of awe.
SIMON: Simon Redfern, professor of mineral physics at the University of Cambridge on being up close at the Bardarbunga volcano in Iceland. Transcript provided by NPR, Copyright NPR.