Pompeii is hitting theaters this weekend, and although, let’s be honest, we’re probably not going to go see it, it did get us wondering which volcano is most likely to blow its top next and engulf us all in boiling lava.
We asked volcanologist Benjamin Edwards, Associate Professor of Geology at Dickinson College in Pennsylvania, for his take on what’s likely to blow when, and where. Obviously, it’s impossible to predict exactly when a volcano will erupt – there are, as he points out, “something like 1,300 volcanoes that are potentially active” – but the following are all likely candidates.
Mauna Loa, Hawaii
Photo: Flickr.com/ Matt MacGillivray
“Mauna Loa is the largest active volcano on the island. It hasn’t erupted in quite a few years and it’s only a matter of time before it erupts again, because it does erupt frequently. It can produce pretty big lava flows that travel quickly, so there’s certainly some danger to the people on the Big Island of Hawaii. It’s such a famous volcano that there would be people from all around the world trying to go see it because it’s so well known for having such a large outpouring of lava when it erupts. Lava flows are special things; they’re just fascinating. It’s like a slow-moving river that’s glowing orange and red and black. They are absolutely incredible. That’s one of the reasons that, when Mauna Loa goes off again - and almost for sure it will, maybe in five years - that’s one of the reasons why it’s a draw, because there are lots of places you can be to see the lava flows from a distance.
“Lava coming down from the summit would be between 1,100°C and 1,200°C, and it could actually flow all the way to Hilo, which is 15 or 20 kilometers away, but it wouldn’t be flowing fast enough that people would be dying in the streets because they couldn’t outrun it. The biggest danger from lava flows would be to structures and things that aren’t movable, because the lava either burns them down or buries them or crushes them.”
Photo: Flickr.com/ Axel Kristinsson
“Hekla erupts multiple times a century and it hasn’t erupted since, I think, the '90s, so it’s actually a volcano that I wouldn’t be surprised to see go off in the next five years. One of the things that’s interesting about Hekla is that it has sort of a deeper plumbing system. The bigger volcanoes often give you a few weeks of warning or even more - you start to get earthquake swarms, you start to get different gases. If it’s an ice-covered volcano, sometimes you see melting early on as magma starts to move. But with Hekla, it’s not unheard of for there to be only a few hours between the first signs of unrest and an eruption. It’s actually something that’s a bit of an issue, because in the summer, it’s quite a popular hiking place. It’s at least a three or four-hour hike, so if you were on top of the volcano and the earthquake swarm started, you might only have a few hours to get down.
“Like Mauna Loa, Hekla’s usually more of a local hazard, although it has had some pretty big eruptions in the past. If the jet stream was in the right position and Hekla decided to have a big blast, it certainly would cause similar problems to what Eyjafjallajökull caused in 2010, and it could potentially be bigger than that eruption. But what happens in Iceland and how it effects Europe is hugely dependent on the weather - if a jet stream is coming across Iceland and then going off to the north, even with a big eruption, most of the ash gets carried up into the Arctic and the Arctic Ocean. In 2010, the jet stream was in a mode where it was actually coming down across Iceland and then cutting straight to the southeast, which brought the ash really quickly over to Europe, so it got much more press. It’s complicated because it’s not just the size and the type of volcano, it really has to do with what the weather’s like when the eruption starts. Based on history, Hekla’s more likely to produce lava flows right now than it is to do something explosive, though - or at least, explosive in a big way.”
Photo: Flickr.com/ _CaTa_
“The whole western side of South America is chock-a-block full of volcanoes. It’s interesting to me because it’s capped by glaciers and snow - when a volcano like that erupts, you get this snow and lava and the contrast is pretty spectacular. Llaima has had several eruptions in the past century and when it erupts, one of the things that can happen is it can melt a lot of the snow and ice. That produces an extra hazard that we don’t see with other volcanoes - big floods. So you have a big explosive eruption and the ash comes down and covers the snow or ice with a thick blanket, and that can melt the snow quickly enough that you get flash floods that come down the river valleys.
“Chile is pretty on the ball when it comes to monitoring their volcanoes – they’ve had two or three eruptions ongoing in the last five or six years. A couple of big volcanoes that don’t erupt very often had big eruptions and it’s something we didn’t hear a lot about in the northern hemisphere. That’s actually another interesting thing about volcanoes - if you’re far away from the equator in the north and south, the effects of a big eruption tend to stay more in the northern hemisphere or southern hemisphere. But as you start to get volcanoes closer to the equator, they can produce gas and ashes that go to both the northern and southern hemisphere. So big eruptions from places like Indonesia, those volcanoes can actually cause more significant global problems, to the point where they can actually change the weather. When Pinatubo erupted in 1991, the following year there was actually a measurable but slight decrease in the global average temperature because of the gases and the ash the volcano put up in the atmosphere.”
Photo: Flickr.com/ Ben Beiske
“Since the 1883 eruption, there have been several smaller eruptions that have rebuilt a volcanic island there - it’s a small island called Anak Krakatoa that has formed slowly over the last hundred years. It has periodic small eruptions, so the kind of eruption I’m talking about in Krakatoa is actually more of a continuation of the eruptions at that small island. It’s mainly explosive, but relatively small explosions, or maybe a little bit of lava. As far as I know, there are no signs that the entire caldera area of Krakatoa is getting another large eruption like the one in 1883. With volcanoes, some eruptions are dominated by melted rock – lava - pouring out of the Earth’s surface, and that’s called an effusive eruption. The other type is called an explosive eruption – that’s when material comes out of the ground as fragments of ash, rather than a liquid. Those eruptions cause a lot more problems, not just locally but regionally - you can still find ash in Texas that traveled roughly 2,000km from Yellowstone Park.
“The reason the 1883 eruption is so famous is that it happened at the right time. The telegraph system had just been put up, so it was probably the most widely broadcast eruption in history up to that point. It was absolutely a big eruption, but there was an eruption in 1815 that was a lot bigger – the Tambora eruption, which has been blamed for causing a winter so bad in the Northeast United States, it caused crops to fail.
Syracuse, New York
“My prediction is that there will be an eruption in Syracuse, NY, today [February 21, 2014]. The story behind that is that Syracuse University has an artist named Bob Wysocki who started making lava flows. He has a big furnace that can melt up to 300kg of rock - we’re actually trying to make underwater lava flows. One of the most common types of lava is pillow lava, which forms on the bottom of the ocean. There are lots of questions about how these things form, so Bob has built himself up about a three-foot by six-foot swimming pool that we’ve already done some experiments with - we poured lava into the pool! The flows he makes are, in order of magnitude, smaller than real lava flows, but you see a lot of the same features as lava flows, so you can design specific experiments to see what happens to lava flow under certain situations. For me, that’s really important because my interest is volcano/ice interaction. Most of the time, when there is an eruption in a volcano, it’s usually too remote or too dangerous to get to, so we have to wait until the eruption is over and then try to figure out what happened. But at Syracuse, we can make these little lava flows that are relatively predictable, so we can measure how thick the ice is, we can measure temperatures, and we can control and understand what’s happening in these remote volcanoes that would be pretty dangerous to go to and understand in the field.”