Announcer: Welcome to Stuff from the Science Lab from howstuffworks.com.
Allison Loudermilk: Hey, guys, and welcome to the podcast. This is Allison Loudermilk, the Science Editor at howstuffworks.com.
Robert Lamb: And this is Robert Lamb, Science Writer at howstuffworks.com. This week we're talking about death by volcano. Which kind of takes me back because when I was a kid, I think everybody had a variation of this game, but me and my sisters would play this game where we'd be in the living room and suddenly somebody would yell out everything but the couch is lava. e'd all have to jump on the couch because if you were stuck on the floor then you were burned alive by lava. Sometimes it was a never-ending pit, but most of the time it was lava. Did you guys do that?
Allison Loudermilk: Yeah, occasionally. It wasn't one of our central games. We were more like ghost in the graveyard type of crew.
Robert Lamb: I don't know that one.
Allison Loudermilk: Oh, really? Ghost in a graveyard? Where you're outside, it takes place a night, and there's somebody who is, I guess, the ghost. Anyway, you have to make a lap around a prescribed circuit and make it back safely.
Robert Lamb: That sounds fun.
Allison Loudermilk: It's, actually, really fun. It's a really good summer game. But we did play the volcano game as well.
Robert Lamb: Okay. Well, yeah. Basically, we were talking about ways - since you weren't actually gonna have your living room suddenly turn into lava and burn you alive, but still volcanoes can be pretty deadly. We're gonna talk about them a little bit here today. Do you have any personal experience with volcanoes?
Allison Loudermilk: Yeah, not so much. I've seen some, but the story that stuck out to me when we decided on this podcast topic was there was this story in winter 2010 about this climber who fell into the crater at Mount St. Helens. Did you hear about that?
Robert Lamb: No, I don't think I did. I missed that.
Allison Loudermilk: Yeah. He was a pretty expert climber. I think he'd climbed Mount St. Helens to the tune of almost 70 times. He was up at the summit and he removed his backpack and he took off his jacket and he was gonna pose for a picture. Why not?
Robert Lamb: Yeah. And he fell into the volcano?
Allison Loudermilk: Yeah, yeah. That cornice gave way.
Robert Lamb: That's a great way to go. I mean, that's like the manliest death ever.
Allison Loudermilk: Oh, I don't know. I've got to debate that because what if you're still living and he's at the bottom wherever he fell and he's wondering if somebody is gonna get to him or maybe he's kind of dying slowly and he sees help because they did actually recover his body.
Robert Lamb: Yeah. But I'm just thinking it's later and they're talking about mountaineers and mountain climbers and they're like, oh, yeah, there's old Carl and he died in that old folks home up there in Coffee County. Oh, how about Doug? Oh, he sprained his leg real bad. He's still around, but he doesn't do much. Well, how about what's his name? Oh, he fell into a volcano. That's the most awesome death ever.
Allison Loudermilk: I guess it is just -
Robert Lamb: Like, people were probably thinking when I'm cremated I want my ashes to go into a volcano. That's just so epic. This guy, that's how he died. If you have to pick a way, that's pretty fantastic.
Allison Loudermilk: Right. So that's one way to die by way o f a volcano. What are volcanoes, again? In case you guys need a quick review, I'm happy to provide such review to you.
Robert Lamb: Yeah. Well, most of the time, we do think about Mount St. Helens or we think of a big fiery mountain, like the kind of place where a dark lord might forge some sort of a horribly powerful ring to enslave the population of a fantasy world. They can be a little more than that. Generally speaking, a volcano is any place on a planet where some material from the inside of the planet makes its way through to the planets surface. Sort of like a pimple or something, except in more geologic terms.
Allison Loudermilk: Right. The geologic terms would be lava, ash, and gases, right?
Robert Lamb: Right. The layers wouldn't be skin, muscle, etc. They would be core, mantle, and outer crust. So magma can rise where two plates meet. That's one way.
Allison Loudermilk: Right. So where the crust of the earth is divided into about 12 different plates, right?
Robert Lamb: Um hm.
Allison Loudermilk: Yeah. Right. Like you were saying, Robert, doing a fine job, magma can rise up where the two plates meet.
Robert Lamb: Right. It's like the ring of fire and all that stuff. It's like wherever they meet you, basically, have this rift where magma can rise. Magma can also push up under the middle of a plate. It's much less common, but the inner plate volcanic activity is caused by an unusually hot mantle material forming in the lower mantle and pushing up into the upper mantle.
Allison Loudermilk: Okay.
Robert Lamb: All right. And this wells up and, basically, creates a hotspot.
Allison Loudermilk: And it's not just some tiny hotspot. It's a hotspot that's hundreds to maybe even a thousand kilometers wide. We're talking about a huge hotspot.
Robert Lamb: Yeah. And due to the unusual heat of the mantle material, it melts, forming magma just under the earth's crust. Then that bursts up and you have a volcano. This is kind of interesting, since a continental plate moves over this spot, the magma will create a string of volcanoes, which die out once the plate moves past the hotspot. So you have situations like the volcanoes in Hawaii, which are created by the spot forming this volcano and then this, it's like an assembly line of geologic strife, if you will.
Allison Loudermilk: Yeah. I mean, speaking of geologic strife, the ring of fire has to take the cake. Incidentally, Indonesia has the most volcanoes.
Robert Lamb: Oh, yeah. They're rife with them.
Allison Loudermilk: Although in the U.S. I feel like Mount St. Helens gets a lot of volcanic credit, but really there are 169 active volcanoes in the U.S. Did you know that, Robert?
Robert Lamb: I did not have that figure floating around in my head. Of course, we have Hawaii, too, and they have some awesome volcanic activity there as well, which I got to see firsthand several years back.
Allison Loudermilk: Oh, did you?
Robert Lamb: Yeah.
Allison Loudermilk: I didn't know you've been to Hawaii.
Robert Lamb: Yeah. A friend of mine -
Allison Loudermilk: Did you honeymoon there?
Robert Lamb: No, no. No, we d id not. We honeymooned in Mexico.
Allison Loudermilk: Oh, right.
Robert Lamb: But this is during a time when I didn't know what I was doing, but a friend of mine, JP Callan, if he's listening, moved out to Honolulu. He had an architect job up there, so he's like, hey, if anybody wants to come visit me, you've got a free place to stay in Hawaii. So I went out there and visited him for as long as he'd put up with me.
Allison Loudermilk: How long was that?
Robert Lamb: So I got to see the - it was awesome. I got to see the volcanoes. Beautiful place.
Allison Loudermilk: Yeah. I was a big fan of Hawaii. I've only been to Maui twice though.
Robert Lamb: Oh, yeah. Well, you can - pretty much any of those islands are great. Even the leper ones, or the one, it's just the one.
Allison Loudermilk: So death by lava, what have you got for me?
Robert Lamb: Yeah. While I was in Hawaii I saw a guy get hit by a bus, but I did not see anybody killed by a lava flow. That's what we're gonna talk about here.
Allison Loudermilk: Did you really see a guy hit by a bus?
Robert Lamb: I didn't see it happen, but I went in to get a coffee, came out, and I'm like, huh, what are they doing over there in front of that bus. It's parked in the middle of the road and it's like some guy with a lei on had been hit by a bus. Yeah. Anyway, back to the lava. All right. So lava flows are streams of molten rock that pour ooze out of an erupting vent. All right. Now, this can come out explosively, like an eruption. Lava fountains like we're used to seeing or used to seeing images of anyway. It can also occur non-explosively where it just seeps out in a slow way. The speed at which lava moves depends on several different factors. It depends on the type of lava erupted, its viscosity, the steepness of the ground over which it travels. If you're up hill from the lava, you're a lot safer than you are if you're looking up at it on a mountain peak.
Also, whether the lava flows in a broad sheet or it's confined to a channel down a lava tube, etc. It's kind of the difference between putting a kink in the hose. Water moves faster through the kink, lava is gonna move faster through a confined space. Fluid basalt flows can extend tens of kilometers from an erupting vent. The leading edges of these flows can travel as fast as six miles per hour, ten kilometers per hour, on steep slopes. When they're confined to a channel or something, they can hit 19 miles per hour.
Allison Loudermilk: Okay. So I wasn't really thinking that death by lava flow was a real certainty for a lot of us who can move quickly, but now that you're getting into some of these faster speeds, it seems like it's posing more of an issue.
Robert Lamb: Yeah. One of the things I was reading is it basically still moves slow enough that most of the time the lava itself is not a risk because, generally, you're gonna hear, oh, the mountain is now spewing fire and ask into the air and it just becomes pitch dark, so maybe I should run away.
Allison Loudermilk: Right. But maybe you're in the middle of a very serious text to your partner, to your girlfriend, boyfriend, you're not paying attention, here comes the lava.
Robert Lamb: Well, more than likely you're texting, hey, I don't know what the shortcuts for this would be like, hey, volcano just erupted, I'm gonna go get a picture of it, and send you a picture with my iPhone. So they run out to the lava to get a picture of it and then get burned alive. That is, actually, the more common form of people getting killed by lava. Or getting around it and suddenly getting cut off from their escape by the flow of lava. One thing that they have to be real careful with on the big island in Hawaii, at Volcano National Park, when I was there, I actually got to go down and walk on the lava flows and get really close to lava where people were being really disrespectful. I don't know. I thought it was disrespectful to bring marshmallows, so you could get your picture made with a marshmallow over the lava flow.
Allison Loudermilk: I wonder if the marshmallows were tasty.
Robert Lamb: I don't know, but it's like - so you get tourists down there around lava and it's a wonder they don't lose people every day. One of the things about this particular area , this is where it's flowing out towards the water and you can walk on where it's become rock, but a lot of times there is molten rock right underneath there. If you don't know what you're doing, you could easily walk out onto an area where there is not all that much rock. It's like walking out onto thin ice and you get killed that way. So, yeah, generally, you're gonna be pretty safe from the lava unless you're stupid or slow.
Allison Loudermilk: So the next method is perhaps not as exciting as lava flow, it's vog. No, I did not say fog. I said vog.
Robert Lamb: Yeah.
Allison Loudermilk: So let's take you into the vog. In June of 1996, New Zealand's Mount Ruapehu erupted violently. It had an ash cloud blotting out the sun for miles and that ash cloud climbed almost 30,000 feet into the atmosphere.
Robert Lamb: It is a classic example of erupting volcano, fire mountain, ash, all of the bells and whistles you'd expect.
Allison Loudermilk: Yeah. We're talking 7 million tons of rock and ash were ejected. But, good news, nobody was killed. At least initially and, at least, not within 60 miles of the volcano. In the cities of Auckland and Hamilton, however, which are located hundreds of miles from Ruapehu, something strange started to happen. There were no warning sounded and the skies mostly appeared normal, but a lot of people started showing up at hospitals. A lot of them started dying of aggravated respiratory diseases. In fact, about 69 people in the two cities died from unexplained respiratory illness that July, according to public health statistics.
So you could surmise that, perhaps, it was undiagnosed flu or something else, but a bunch of researchers had just published a study in the Journal of Atmospheric Environment think no. They think it was invisible particles of acid coated volcanic ash wafting into the cities. I mean, you don't want that stuff in your lungs.
Robert Lamb: Yeah.
Allison Loudermilk: Over in Hawaii, Kilauea has been erupting since 1983, oozing streams of lava in a relatively peaceful volcanic way.
Robert Lamb: This is where we get the term vog, right, because it's volcanic fog or voc. Little portmanteau going on there.
Allison Loudermilk: Right. I wonder how Hawaiians feel about their vog versus the Los Angeles folks with their fog. Which would you rather have?
Robert Lamb: What's in Los Angeles?
Allison Loudermilk: Fog. Smog. Oh, right. Right. Right. Los Angeles has smog, San Franciscans have fog, and Hawaiians have vog.
Robert Lamb: Yeah. I think vog is definitely more exciting.
Allison Loudermilk: Yeah. Vog is pretty much more exciting. So, like I said, Kilauea has been erupting since 1983, but these are pretty mellow eruptions as far as eruptions go. The gas from the eruption is rich in sulfur dioxide. What happens is that trade winds regularly waft it towards small communities on the southern part of the island. Along the way, some of the gas can morph into these hazy sulfate particles. Together, this is what makes up Hawaii's much maligned volcanic smog a/k/a fog.
Robert Lamb: Yeah. And they started looking at how it was affecting people. Between 2004 and 2009 they found that the high exposure to vog nearly doubled the risk of coming down with sore throat or asthma attack. It also elevated bronchitis risk in adults by 57 percent actually.
Allison Loudermilk: Yeah. And, of course, children pretty susceptible to vog related diseases with risk of upper respiratory infections nearly doubling. The likelihood of an asthma attack rose by a factor of five. Also, bronchitis, which you just were talking about, the risk for bronchitis was six times higher. So vog poses a serious public health threat.
Robert Lamb: Yeah. They started kind of where they're doing a lot more real time air quality monitoring. Just making sure that they're on top of it and they're aware of the situation.
Allison Loudermilk: Yeah. It's a sparsely populated area by the name of Ka'u that's by far the most grievously affected.
Robert Lamb: Yeah. I guess we drove through Ka'u when we were there.
Allison Loudermilk: Did you know that Hawaii also boasts the rainiest place on earth?
Robert Lamb: Seems like I have heard that. Well, that's why they have so many rainbows. They have the rainbow on the license plate and all.
Allison Loudermilk: Yeah.
Robert Lamb: It's amazing. You go to the Volcano National Park and you can see complete rainbows inside a crater. I walked under a rainbow and looked back and saw it.
Allison Loudermilk: That's pretty darn cool.
Robert Lamb: One point we were at the top, looking down into a crater, looking down at a complete rainbow underneath us. It was crazy. I didn't even think it was possible. So, yeah, our next method that a volcano might use to attempt to kill you is kind of a double, pyroclastic flows and lahars. These are pretty awesome, unless you're in their path. A pyroclastic flow is a cloud of hot volcanic gas, ash, and volcanic bombs that sweep down the volcano sides and other steep hills at speeds approaching 100 miles an hour.
Allison Loudermilk: Wow, that's fast.
Robert Lamb: Yeah.
Allison Loudermilk: That's a heck of a lot faster than those silly lava flows.
Robert Lamb: Yeah. This one is really far more of a killer than just lava flows. When a volcano erupts violently, it's large volume of rock to just pulverize in the explosion and they're reduced to these tiny particles. These mix with high temperature gases, ash, larger pieces of rock, and it all forms together into this big, hot cloud. Like, imagine opening your oven to check on the cookies or whatever and that blast comes out, just imagine a huge blast like that except intensely hot.
Allison Loudermilk: And it doesn't smell like cookies.
Robert Lamb: Right. Does not smell like cookies. Now, if you're cooking pork, I guess, that might be accurate because of all of the burning flesh. This is a great example.
Allison Loudermilk: Oh, Robert. I can't believe you just took it there.
Robert Lamb: Well, we're talking about ways it would kill you. The classic example of this is when Mount Vesuvius erupted in Italy back August 24th in AD 79. It was on the 25th that the pyroclastic flow came down and hit Pompeii, so it damaged the walls of the buildings. It ripped roofs off and it killed everybody in their path. They found about 2,000 bodies later when they excavated the site. This is what's really weird and grotesque is that they discovered all of these fractured skulls among the Pompeian dead, signs that, basically, the pyroclastic flow heated them up so fast that it boiled their brains in their skull and shattered their heads like eggshells.
Allison Loudermilk: Again, a very nice image.
Robert Lamb: Yeah. The other thing to worry about is the lahar. All right. This is actually caused by the pyroclastic flow. When the pyroclastic flow mixes with water then the ash and water mix can form into a type of mud that sets like concrete the instant it stops. Think of it as a pyroclastic mudflow really. This happened with Mount St. Helens, pyroclastic flow melted the snow and the ice on the upper slopes and it formed all of this fast flowing mud, swept down the mountain and into the river. It instantly heated the river up. The mudflows ended up going through houses, picked up trucks, cars, etc. Then once it settled into place it just sits.
Allison Loudermilk: Yeah. It's like a moment in time of destruction. Just frozen forever.
Robert Lamb: Yeah. Like when Mount Vesuvius went off, the town of Herculaneum was hit by the lahar. They've been digging around in that for a while now. Everything was just sealed up in this concrete.
Allison Loudermilk: So this is one of those ways to die that if you're looking to die a fast death, I would think that this would be the way to go.
Robert Lamb: Yeah. They pyroclastic flow is definitely gonna hit you hard, just instant death.
Allison Loudermilk: Yeah. So the next one is a volcanic winter. If you've ever sat by a campfire, and I know you guys probably have, you're probably noticed the smoke and the bits of ash that are rising from the flames, these are the product of combustion. The smoke you see ascending out of an erupting volcano, on the other hand, consists mostly of these tiny mineral particles formed by the explosive release of gases. Once volcanic ash is airborne, three factors determine how far it will travel before falling back to the earth. Can you guess one of the factors?
Robert Lamb: Particle size.
Allison Loudermilk: Right. The larger the particle, the closer it's gonna fall to the volcano. The smaller the particle, the farther the winds are gonna be able to carry it and drift it into a town near you. Another factor that determines how far it's gonna fall from the volcano is the wind speed and direction. I mean, what kind of winds do we have blowing? If it's just a strong direct wind then the volcanic ash is gonna blow in a relatively straight line, but throw some storm type winds into the mix and they're gonna be much more effective at distributing volcanic ash in many different directions. Eruption type also determines how far away the ash is gonna fall. There are several different kinds of volcanic eruptions. Their severity plays into both of the above factors.
If you have a particularly powerful eruption, then that's going to be able to blast particles, perhaps, into the upper levels of the planets atmosphere. If you have kind of a non-descript run of the mill explosion then the volcanic ash won't be blasted quite as high into the atmosphere. So once in the air, the volcanic ash kind of mills around and it joins other dust particles and it forms what's called condensation nuclei, which water vapor condense around to form clouds. Some violent eruptions can even add volcanic ash cloud cover to the atmosphere to drop global temperatures by several degrees. This is sort of like your nuclear winter. Back in 1883, the eruption of Krakatoa lowered global temperatures by 2.2 degrees Fahrenheit.
Robert Lamb: Yeah. In fact, some of these are cases that scientists point to when making arguments and calculations about nuclear winter.
Allison Loudermilk: There's one theory called the Toba Catastrophe Theory, so named for Lake Toba in Indonesia. According to this theory, modern human evolution was affected by a recent large volcanic event. That's the thought.
Robert Lamb: And by recent we mean 70 to 75,000 years ago, but it's still pretty recent in geologic terms.
Allison Loudermilk: The even that they point to, they think there was a category 8, or what's called a mega colossal eruption, on the volcanic explosivity index.
Robert Lamb: Yeah. This was a six-year-long volcanic winter fall of this. That was followed by an estimated 1,000-year-long instant ice age.
Allison Loudermilk: Yeah. Of course, also followed by decimation of humanity.
Robert Lamb: Yeah. By recent, we mean 70 to 75,000 years ago.
Allison Loudermilk: Yeah. The Toba Caldera in Indonesia underwent a category 8 eruption on the volcanic explosivity index, so this is the mega colossal as it's so dubbed.
Robert Lamb: That's the actual term.
Allison Loudermilk: Yeah, mega colossal.
Robert Lamb: I wonder what it's over. Is it mega awesome after that?
Allison Loudermilk: There is some pretty serious ramifications after this particular eruption. There was a six-year-long volcanic winter. Pretty much there was a 1,000-year-long instant ice age that followed Mount Toba's eruption. Of course, modern man was decimated. The population of modern man just plummeted.
Robert Lamb: Yeah. Fell to, they think, around 10,000 adults between 50 and 100,000 years ago. The survivors, they think, would have found refuge in isolated tropical pockets, mainly in equatorial Africa. Meanwhile populations living in Europe and Northern China would have been basically wiped out. Just a 12 degree change in temperature can have just catastrophic effects.
Allison Loudermilk: Right. So that's volcanic winter. Why don't you talk to us about tsunamis and earthquakes?
Robert Lamb: Yeah. Well, earthquakes related to volcanic activity can produce hazards, which include ground cracks, ground deformation, and damage to manmade structures, obviously. There are two categories of volcanic earthquakes. Volcano tectonic earthquakes and long period earthquakes.
Allison Loudermilk: Okay.
Robert Lamb: All right. Volcanic earthquakes are pretty simple to imagine. All right. A volcano erupts and this creates all of these stress changes in the solid rock, due to either the injection or withdrawal of magma. You have all of this liquid rock moving around. Suddenly there's areas that used to have rock under them end up falling in. Other areas blast out and produce all of these large ground cracks. The earthquake can occur as rock as moving in to fill the spaces where magma is no longer present and they just happen. They're just a part of the volcanic eruption. The other category are long period earthquakes. These are produced by the injection of magma into the surrounding rock.
These are the result of pressure changes during the unsteady transport of magma. These are the type of seismic activities that scientists will study and be able to say, like, well, the seismic activity is increasing around this particular volcano.
Allison Loudermilk: We better watch out for eruption.
Robert Lamb: Exactly. Yeah. Whereas the other type just is a part of the eruption and a byproduct of the eruption.
Allison Loudermilk: I see.
Robert Lamb: Yeah. Then, of course, if volcanoes are producing seismic waves, this can also produce tsunamis, especially in the case of submarine volcanoes. They quickly collapse downwards, spew forth lava, which heats the surrounding water quickly, which generates these massive waves, which can be catastrophic.
Allison Loudermilk: So Krakatoa, the explosion in 1883, actually had a pretty large impact on the population due to a crazy tsunami. The tsunami in that instance killed about 36,000 people.
Robert Lamb: So, yeah. I think out of all of the ones that we've mentioned, I think the way to go is falling off of a mountain into a volcano.
Allison Loudermilk: No, I disagree. I think that I would much rather be gone in one of those pyroclastic flows easily.
Robert Lamb: You'd rather your skull explode?
Allison Loudermilk: Yeah. Yeah, I would, Robert.
Robert Lamb: Okay.
Allison Loudermilk: That's the way I want to go, I think.
Robert Lamb: All right. If you want to find out more about volcanoes and other topics, you can also check out our blogs, which you can reach via the homepage.
Allison Loudermilk: Or you can send us an e-mail and tell us about your volcanic experiences at firstname.lastname@example.org.
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