IRA FLATOW: For the rest of the hour, the volcano on the island of La Palma continues to erupt. It’s been going for over a month now, causing destruction and evacuations on the island and dramatically changing the coastline. But elsewhere on Earth, a volcano can be a major tourist attraction. Here to talk about the terror and wonder of volcanoes is Robin George Andrews. He’s a volcanologist turned science journalist and author of the upcoming book, Super Volcanoes. He comes to us from London. Welcome to Science Friday.

ROBIN GEORGE ANDREWS: Hey, thanks for having me.

IRA FLATOW: We’d love to have you. Is there another– there is another eruption elsewhere this week, is there not?

ROBIN GEORGE ANDREWS: Yeah, this week, Mount Aso in Japan on its western isle of Kyushu suddenly woke up. Well, not suddenly. It was grumbling for a while and hissing and spitting. But a large explosion cloud emanated from its active crater this week. And there’s some amazing footage of it online of billowing clouds of superheated gas and dust. But fortunately, the area is not densely populated. And it’s quite far from any cities or anything. So hopefully, it should be fine. And so far, no casualties.

IRA FLATOW: That’s good to hear. So let’s talk about this volcano in La Palma that has been erupting for weeks. What’s the latest?

ROBIN GEORGE ANDREWS: Well, the latest is that it’s going to keep on going, really. I mean, it’s one of these volcanoes that seems to quite enjoy sticking to a routine. And its routine right now is to just keep pumping out lava. So there’s no sign that it’s going to do anything drastically different at the moment. It’s just going to keep erupting lava. But yeah, it’s whether there are things in its way, structures in its way or not, it’s just going to keep [INAUDIBLE] eating itself until, at some point, it will stop.

IRA FLATOW: Yeah, so it’s not an exact science about volcanoes, meaning we don’t know when to predict they’re going to happen or how long they’re going to make their run.

ROBIN GEORGE ANDREWS: No, no, knowing when a volcano is about to erupt is much more of a known science, but not known exactly. So that’s why scientists like using the word “forecast.” They may kind of– volcanoes normally give signs that they’re going to do something. It’s not necessarily erupt, but this volcano started swelling up. It started playing this little seismic symphony that kind of indicated that it was magma rising to the surface. So it seemed pretty likely it was going to erupt roughly where it did start erupting. So that was kind of forecast in advance.

But in terms of when a volcano is going to stop erupting, it’s a big unknown. Sometimes volcanoes can be full of magma still, full of eruptable magma like Kilauea in 2018. And one day, it will just stop. But sometimes they can keep going on for months of weeks. They can peter out, have another crescendo. That is the real unknown.

IRA FLATOW: This is Science Friday from WNYC Studios. And when they do erupt, they can produce different kinds of lava flows.

ROBIN GEORGE ANDREWS: Yeah, so volcanoes erupt quite differently. Even each individual eruption from a single volcano is quite different. But there are kind of a few main types of eruptions. So what you’re getting on the Palma is called an effusive eruption. It’s kind of coughing every now and then. A bit of gas gets stuck in its throat. And that’s where you get those little explosions. It’s mainly just lava oozing out, a bit like someone standing on a tube of toothpaste or something.

And Mount Aso in Japan, it’s an explosive sort of eruption, where you have lots of trapped gas and really sticky magma, so the gas can’t escape very easily. So when it does break through to the surface, it’s as if you’ve shaken up a Coke bottle and then just decapitated it. It will just rush out in one big go. So quite different eruption styles. And yeah, it varies from volcano to volcano. And there are thousands around the world.

IRA FLATOW: And sometimes they can be quite destructive, moving very quickly down the side of the volcano.

ROBIN GEORGE ANDREWS: Yeah, yeah, so lava is your best chance. If you want to try and outrun an eruption, lava is your best chance. I mean, if it’s going down slope, it’s obviously going to move faster. But generally speaking, if lava moves on a flat surface– I don’t know if you saw footage of the eruption earlier this year in Iceland, and it’s on Reykjanes Peninsula. But that eruption was happening basically in a valley, and this lava was very slowly oozing out. And you could outwalk it. People actually went up to it and started cooking things on it. There were wedding proposals in front of it. There were gigs in front of it. It was considered a tourist eruption because it was so safe and so kind of predictable in that sense.

But every now and then, you kind of get weird chemistries. And there’s a volcano in Africa called Nyiragongo in the Democratic Republic of the Congo. And that lava can sometimes move somewhere between 40 and 60 miles per hour.

IRA FLATOW: Wow.

ROBIN GEORGE ANDREWS: So good luck outrunning that. And yeah, if you’re looking at these explosive clouds of hot ash and gas, there is no chance you can outrun those or outdrive them. These things move so fast, like sometimes 70 miles an hour or hundreds of miles an hour sometimes, and actually are so forceful. They can actually go uphill. So they’re the real things you have to worry about, I think.

IRA FLATOW: People have this mental image from Hollywood of a huge pool of molten rock right beneath the surface. Is that really what’s going on?

ROBIN GEORGE ANDREWS: That kind of pool, that kind of lava-like bubbling thing, that kind of Mount Doom Lord of the Rings thing. Lava lakes are incredibly rare, actually. I think there’s only six or seven volcanoes on Earth that have got long-lived, multi-year lava lakes. And no one’s quite sure why that is. It’s like a direct pipe into the sort of magma reservoir inside a volcano. So they’re really rare.

Normally, what you have with volcanoes is you either have something mountainous or you have something like the volcanoes of Hawaii, which are really big mountains, but they’re kind of very spread out. Or you have just like an Iceland. That eruption, it just came out of cracks that open up in the ground as the magma forced its way through.

IRA FLATOW: Is there ever really such a thing as an extinct volcano?

ROBIN GEORGE ANDREWS: Yeah, yeah, so there’s loads. I mean, an extinct volcano, I guess in general terms, means a volcano that has no chance of erupting ever again. And essentially, once a magma supply to a volcano stops, it dies kind of thing. It’s almost like oxygen to the brain, really. I mean, volcanoes will inevitably eventually die out.

It’s just, it seems hard to imagine, really, because they don’t really operate on human timescales, right? They are way beyond our kind of existence. There are volcanoes on Earth that are as old as our species and even older. So volcanoes can die out, but some can live seemingly forever on our timescales. But eventually, sadly, everything dies, including volcanoes.

IRA FLATOW: What amazes you the most about them? I see you’re very excited. You talk about volcanoes. You’re right about them. What have you found that amazes you most?

ROBIN GEORGE ANDREWS: I think they kind of come across as these sort of tempestuous giant beasts. I mean, they’re much better understood than they were 2,000 years ago, say, when people were describing the eruption of Vesuvius that buried Pompeii. I mean, people consider that to be the end of the world kind of thing. It was so frightening and so strange and surreal and kind of awe inspiring in a sort of perverse way.

And even now, when you speak to volcanologists or when I see these things, even though you know the science behind them, you know the physics of what they can do, they still have that visceral sense of awe. It kind of shakes you to the bone sort of thing. And I think the best way anyone has described it to me is someone that lives on an island called Santorini, which is an active volcano. They said that volcanoes bring fear and joy together. And I can’t think of many things that simultaneously make you feel afraid for your life, but exhilarated to be alive. And I think more than any scientific thing, that’s the thing that really hits me. I can’t think of anything else quite like that.

IRA FLATOW: Robin, thank you for taking time to be with us today.

ROBIN GEORGE ANDREWS: Oh, thanks for having me. Anytime.

IRA FLATOW: Dr. Robin George Andrews is a volcanologist turned science journalist and author of the upcoming book, Super Volcanoes.

Copyright © 2022 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of Science Friday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies/