IRA FLATOW, host:
You're listening to SCIENCE FRIDAY from NPR News. I'm Ira Flatow. It wasn't too long ago, a few weeks ago that Louisiana Governor Bobby Jindal denigrated something called volcano monitoring as sort of a waste of money. And well, they're denigrating it there in Alaska today, where they're seriously watching a volcano. Alaska's Mountain Redoubt continues to spurt and sputter. It began erupting last Sunday, and since then scientists at the USGS has been keeping a close eye on this 10,000-plus-foot volcano. And it's latest eruption occurred earlier this morning, sending a plum of ash to an altitude of 32,000 feet.
And the volcano activity has caused some airline flights to be postponed, has disrupted the operations of some fuel oil terminals in the area, and put the residents of Kenai Peninsula on high alert. But don't expect a lava to start flowing down the side of Mt. Redoubt anytime soon. Joining now to tell us why and give us an update on the activity is my guest David Schneider, a Geophysicist at the US Geological Survey's Alaska Volcano Observatory. He's on the line with us now. Give us an update, Dr. Schneider. What's happening?
Dr. DAVID SCHNEIDER (Geophysicist, US Geological Survey's Alaska Volcano Observatory): Well, our latest eruption was this morning at about 8:40 a.m. local time, and it was another pretty highly explosive eruption, put an ash cloud up to about 50,000 feet this time.
Dr. SCHNEIDER: But it's not drifting towards any heavily populated parts of Alaska. It's been a pretty busy week here.
FLATOW: Mm-hmm. Is it dumping ash? It's not dumping ash on anybody yet, though.
Dr. SCHNEIDER: Well, they don't really live near the volcano. And so, in this, the way the wind is blowing today, it's headed away from the - the populated parts of Alaska.
FLATOW: And the last time we had an eruption like this was when?
Dr. SCHNEIDER: About 12 hours prior to that.
(Soundbite of laughter)
FLATOW: Well, I…
Dr. SCHNEIDER: Yeah. We have had over 10 explosive events here in the past week. Prior to that the most recent activity at Redoubt was in 1989 to 90 over a period of about four months or so.
FLATOW: Thank you for being kind and anticipating what I really wanted to ask you.
(Soundbite of laughter)
FLATOW: Well, you know, the people have a vision of a volcano erupting and sending - spewing out the ash and dust, the clouds, and then all this hot red lava coming down the side.
Dr. SCHNEIDER: Yes. This is a kind of boring lava for a lot of people. You know, it's a very viscous type of lava that doesn't really flow. And that leads to its explosivity, because it doesn't flow out of the vent. It tends to plug it up until the pressure becomes so great that it gets blasted out. Or, in the case of Redoubt, the dome continues to grow on a very precarious slope and it just fails due to over steepening. And that failure, that gravitational failure will sort of uncork the bottle, if you will.
FLATOW: Mm-hmm. And volcano watching, can you tell a volcano is going to be active before it actually happens?
Dr. SCHNEIDER: If the volcano is instrumented, we can give some advance warning. We've been watching read out, really, since last fall. And when - increased our level of concern there for aviation and for ground hazards back late last year. And so, people had a fair bit of warning here to make preparations for ash fall and for the airlines and actually the Air Force base here, just north of here in Anchorage, to redeploy some aircraft as well.
FLATOW: Give us an idea of the geology that we're talking about here. We know about Mount St. Helens on the area down there along the American Pacific and the Seattle area. Is this is the same as the Cascades? Is it the same kind of chain that goes up the coast into Alaska?
Dr. SCHNEIDER: Yeah, that's correct. There's about 50 historically active volcanoes in Alaska that stretch about - along about 1,200 mile arc from just west of Anchorage, all the way out to the tip of the Aleutians. So, if you picture the - you know, usually, Alaska's down there south of California in most maps, but there's an arc of islands that stretches out across the North Pacific, and those are mainly volcanic islands. You know, some of these volcanoes rise up, you know, in excess of 10,000 feet.
And readout's quite spectacular, because it's - you know, it's altitude's about 10,000 feet, but it's only about 25 miles from the ocean. And so there's a quite a lot of relief there visible from the Kenai Peninsula. And you can even see it here from Anchorage.
FLATOW: So, is this part of the famous Ring of Fire?
Dr. SCHNEIDER: Absolutely, this is the northern branch of the Ring of Fire. And, you know, these volcanoes tend to erupt explosively because of the magma type that's produced.
FLATOW: So there's not going to be the lava dome here?
Dr. SCHNEIDER: Well, there be a - we're anticipating at some point that Redoubt will stabilize and produce a lava dome, like it did during 1989 to 90, where there was a whole series of domes that were in place. There just won't be much of a flow of lava down the slopes. It just piles up because it's a very, very sticky substance.
FLATOW: And the, as you say, these volcanoes tend to explode rather than flow around.
Dr. SCHNEIDER: Yeah. That's right, just based mainly on the type of lava that are produced. We do have some volcanoes further west in the Aleutians that produce more of a lava flow type of eruption. But you can get really good pictures of those, because they're underneath the clouds.
FLATOW: Yeah. Well, tell us what kind of sensors you have. Where do you put them? How do you monitor a volcano?
Dr. SCHNEIDER: Sure. Volcanoes are monitored - our bread and butter is a - seismometers. And those are placed in networks around the volcano because the precursory earthquakes tend to be very small, maybe magnitude ones or twos, and so - at largest. And so the sensors need to be very local to the volcano. Then we put some farther away because typically what happens during eruption is seismometers are destroyed. In some volcanoes, we'll have real time, GPS sensors that can telemeter the data back, radio the data back to the observatory, and can measure deformation of millimeters.
That would give some idea of the volume of magma that might be in the volcano. We conduct overflights that measure volcanic gases, and we use satellites routinely to look down and look for evidence of increased thermal activity.
FLATOW: And how many - you mentioned there were dozens of these volcanoes. How of them are actually monitored?
Dr. SCHNEIDER: You know, we - of the 50 historically active volcanoes in Alaska, about 30 of them have real-time seismic monitoring networks. And a smaller - a much smaller number have - continuous GPS receivers on them.
FLATOW: And will you get closer to try to see what's happening actually inside the volcano?
Dr. SCHNEIDER: You know, closer's a - you know, we - closer's never good. And so we can do quite a bit of work safely by taking overflights and looking down on the volcano, measuring gas. We have thermal imagers - a thermal imager that we can use out of a helicopter to take the temperature of the volcano remotely. We also Web cam - a battery powered Web cam just north of the volcano that sends us back information, to give visual observation as well. And what's really become very valuable in this eruption are a couple of weather radars. One, just the regular weather radar, FAA weather radar located about 40 miles away, and then a new USGS radar we just installed last Saturday…
Dr. SCHNEIDER: …it just became operational - to scan back and forth very rapidly over the volcano to detect an ash cloud.
FLATOW: Wow. So you're going to be watching this very closely.
Dr. SCHNEIDER: We have been. It's a bit of busy week. You know, it's been busy year in Alaska, actually. This is the third major eruption of a volcano since July. We had two out in Aleutians in July and August that were very large explosive eruptions that produced drifting gas and ash clouds that disrupted aviation across the Lower 48.
FLATOW: So, it seems like it's making it's way around the rim, there. It started out in the Aleutians…
Dr. SCHNEIDER: It does seem to be that way - kind of feel like a slot machine where you pull the lever and see which, you know, how the bars line up.
(Soundbite of laughter)
FLATOW: So this is an active season, so to speak. Would you expect more, then? More volcanoes to erupt?
Dr. SCHNEIDER: You know, right now, the ones that are active, we can - where there's earthquakes occurring, we can give a more short-term forecast. But, you know, quiet for the next day is the same as quiet for the next year. I mean, for things that are quiet, there's differentiating between stages of quiet.
Dr. SCHNEIDER: So we'll just keep our eyes and ears on the ground here to see what's going on.
FLATOW: Thank you, Dr. Schneider.
Dr. SCHNEIDER: You're welcome.
FLATOW: David Schneider, out there volcano-watching. He's a geophysicist at the US Geological Survey's Alaska Volcano Observatory.
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