How Volcanoes Work

especially not particle physics or spooky physics. It's pretty straightforward. Really. It was very richly detailed dance and structuring content. But really, if you break it down, volcanoes, well that's what that's what we're paid to, due Chuck, and that's what we are going to do. Let me do my introt. First, you ever see Joe versus the Volcano? One of my favorite all time movies all time, like probably top five. I've seen it at least twelve times. It's so great,

the pre serious Tom Hanks best role. Yeah, I think so beats the tired of bosom buddies. I'm a big bachelor party guy. Are you really? Um? But In this movie, he is sent to Wapani Wu right, which means a little island with big volcano to write to jump into the big woo to basically appease the wall ponies. Um who needs somebody to sacrifice himself into the volcano, to call him the volcano God. So everything keep going out right and they can keep drinking their orange soda, which yeah,

they're famous for loving. Yes, was it fanta? Uh? I think it was in the brand for the movie? Um? So you remember then when he jumps in. What happens? Well, I don't want to spoil it for anybody, but you remember what happens? Right? Okay, Chuck, do you realize that, as of this week, we've reached a weird point in our life where we can explain what happened Yeah in that movie because it's not explained by the great John Patrick Shanley who wrote and directed that. No, we needn't

need to because it's a movie. Yeah, but isn't that weird that were we sitting next to our other significant others watching this movie, we could turn to them and say, here's actually what happened, and this is the type of thing that just happened. Yeah, of course it really wouldn't happen that way, but well, we'll figure it out. I don't want to ruin the movie for anyone who hasn't seen it, because we've been chastised for spoiling like thirty year old movies before in series that ended like ten

years ago. Yeah, good series, thought phoned home. Let's talk about volcanoes and how they work, Josh. A volcano, a lot of people might say, is a big mountain with a square top that's bits fire everywhere and kills people. I don't know about square top. That is not true, because any place on the planet Earth where the Earth, the inner Earth, leaks out into the outer Earth, is a volcano wherever Earth gets a boo boo. Yeah right,

it's exactly right. Yeah. So the Earth is composed of three we should we should really just do the broad stroke basics real quick. The Earth is composed of three general mega layers. Right, You've got the thinnest layer, which is the outer crust, which is what we walk around on, which is the bottom of the ocean, the kind of things deep in land. And that sounds no on yes, you're right, that sounds super big, but that's actually really thin.

So from its thinnest part at the bottom of the ocean, it's three miles down, we're thick up to like you said, yeah, forty four miles right, and then under that you've got the mantle, right, and then you have the inner core, which is um where the the inner core the inner earth people that right, Yeah, And the mantle is the biggest part, really really hot but not melty because of one word that is the key to all things volcano pressure.

Pressure pressure. Any time, like everything about volcanoes is pressure related. It seems like it's, yes, it's hot enough this so this mantle it is solid, but it's so it's hot enough to melt, but the pressure is so great it can't melt. It can't be liquid. It's forced to stay in this solid form, right. Um. The other key thing that we need to we need to touch on before we get into volcanoes is the continental drift theory plate tectonics.

Right that there are set at least seven large plates and some minor plates as well that are the outer crust that are moving over the um mantle via the athenisphere. And it's like this kind of liquid layer, this lubricating layer between the crust and the mantle. Right. And then so any time these boundaries where these boundaries are, there's there's a potential for volcanic activity. Right, But that's not

the all encompassing explanation for volcanoes, right the right. There are several ways that volcanic activity can occur as far as plate tectonics goes. Let's cover those first, Chuckers, I'll take the first one. Uh, these plates can move away from each other, sometimes not necessarily toward each other. They can move away when they move away from each other. Um, if you're if it's over water, I'm sorry, underwater. Under the water, it's a specific subsurface. Subsurface, then that's an

ocean ridge. If it's under the land, it's a continental ridge. And Uh, these plates drift apart, and then the mantle all of a sudden doesn't have as much pressure, so it can actually melt finally because it's so hot, and then it bubbles up through the little cracks there. Then once it gets there, it gets cool, hardens again, forms an all new crust and kind of just fills up that gap. And that's called spread spreading center volcanism. And

that's where two plates are moving apart, moving apart. Now, if you want to talk about subduction zone volcanism, which I do feel allow me. That's where two plates are moving together. And if you remember from the earthquake podcast, we covered a lot of this and that too. A subduction zone is where one where plates are pressing up against one another and one is pushed under the other. Right, this forms a trench, a hole in the earth big time. Okay.

So with the spreading center volcanism, magma flowed out because of this, uh, this lower pressure, it was allowed to go to its liquid form. With um subduction. We haven't said what magma is. That's liquid rock. Nice, very important it is. This is the this is what makes up the mantle for the most part as well. Right, So this is the stuff that can that is very hot but is under so much pressure it stays solid. Well,

I think it becomes magma once it turns fluid. Okay, and then once and here's the distinction between magma and lava once it exits the earth, lava, it's lava. So go ahead, okay, nice one, chuck, good catch um. So with subduction zone volcanism, uh, the magma actually the melting point is lowered with the introduction of water. So either water enters the trench created by this subduction zone or um ambient water from the rock around it enters it,

or it's like squeezed out of it exactly. So either way, this introduction of of water lowers the melting point and allows this, uh, the mantle to become magma, as is its destiny. Right, So that's colliding and then shifting under one another subduction you can also collide and you just collide. You meet each other head on, two plates collide and boom, you've got mountains, not volcano right, right, But this is

usually just a subduction zone that hasn't happened yet. Eventually one of them is probably gonna slip under the other and but for the kind of just like pull of rams. Yeah, and then you've got plates moving up against each other. I think that was a slip strike fault, wasn't it in the earthquake podcast, I don't remember. I think it was where they're just like one's going south and one's going north. Um, that forms a transformed plate boundary and

there's almost never volcanic activity. Uh, there's another way they can form, and this is kind of a cool one, uh, interplate or hot spot volcanic activity. Right, we should say that everything we just talked about, all of those were found along plate boundaries. And this is like within a solid plate, right, Yeah, within a plate, you can get a hot spot in the middle of it because the

mantle basically forms a hot plume. It comes up from the bottom and gets hotter and hotter, and then eventually reaches you know, right underneath I guess, I guess the lithosphere. I guess the lithosphere and creates a hot spot, and it's really an unusual heat. It forms magma right under the earth crust and that stays there, but then the

plates move over it. And as each plate moves over it, it forms the whole string of little volcanos, which is how the Hawaii volcanoes were created seventy million years old. By the way, this is a very slow process, but it is a process if you sped it up really fast and be like, okay, yeah, this plate is moving over it, and that's that's that hot spot volcano. Right.

Interplate volcanic activity is what it's called. Yeah, And I think they point out that most of the land volcanoes are the subduction zone that you mentioned, and then the hot hot spot ones and then in the ocean it's mostly the um spreading center of volcanism I belief, yes, right, yes, all right, So Chuck, we've got magma, right, yeah, Or let's say we don't have magma, we have a mantle. Yeah. And then something happens. So this this mantle shifts a

little bit in starts to move upward. Right. Um. Something is something is given way to the downward pressure of the rock surrounding it. And so this magma, which is hot, it's just under a lot of pressure. Uh, And it wants to be liquid. It's less dense, and it's able to move up. The further moves up, the less pressure there is. So it's just gonna keep going upward and upward and upward. And that's how magma starts to move

towards the Earth's surface. Right. And one thing I used to build ponds for a living, and one thing that is, uh, you'll find when you ever try to build a pond. Water is very lazy and it wants to go to the path of least resistance. Liquids are, right, So it will always find something you overlooked and cause a leak. Same thing I imagine with lava or magma. It's liquid, so it's going through any crack or crevice that can find.

And as long as the upward pressure created by the lower density of the magma is greater than the downward pressure of the surrounding rock, it will keep going up. Yeah. But once there is enough pressure, like let's say it just kept going up and eventually with spew out and

you've got a volcano. But if there just happens to be enough pressure and it's like no stop, then it kind of has a little waiting zone in a magma chamber, right, and it just fills up and it's like I can wait seventy million years, right, don't don't be a mistaken brother. Don't there that that We just sounded like zazy top

um Jerry like that, so chuck um. That explains how lava enters the Earth's crust, holes in the Earth's crust and creates um what we'll talk about in a second Hawaiian type volcanoes Hawaiian type eruptions, I should say, we're basically the lava is just coming out, bubbling up over the surface and flowing real slowly um creating little lava ponds, right,

and creators and stuff like this. Just it's cool looking, not very dangerous if you can walk at all, yeah, I mean it's slow, right, or even drank yourself slowly, you could probably beat the lava. But the one that everybody wants to know about our eruptions, like the spectacular, like the um Iceland volcano. Right, I'm not even going to attempt a pronunciation of this, which, by the way, caused at least one point seven billion dollars to the airlines alone in lost revenue. Yeah. Um, it was a

strato volcano by the way. We'll talk about that in a minute. Okay, yes, but with a huge explosion. It's not just this lower density of the magma now, it's it has to do with the gases inside, and magma is what magma eats, right, Yeah, And I mean this is sort of like the It reminds me of the Lake Nyos exploding lakes. It's it's a build up of

gas pressure internally within the magma. Uh, it's a lot of dissolved gas and they're they're stuck that way dissolved, which is all fine, and they're kept you know, thanks to pressure confined in there. But when the vapor pressure gets greater than the pressure surrounding it, it forms little vesicles, which are little gas bubbles, and then it's time. And that's when you know you've got some trouble because those bubbles they gotta get out. It's like a soda soda can.

It's exactly like it's the exact same principle of a soda. Right. So if you open a soda, all the bubbles rushed to the top, and that's if it's just a regular old, non shaking touched it or anything. If you shake it up, you're actually mixing those bubbles in with the liquid. So when those bubbles rushed to the top, they're going to bring a lot of the liquid with them. This is the same exact principle that's behind a volcanic eruption. Okay, but in this case, magma is the soda exactly, and

the bubbles are the gases from the dissolved rock. Okay, right, yeah, I'm with you. So then there's two factors you said that um that pressure was had everything to do with volcanic activity with eruptions, there's two um two factors, two general factors that really have an effect on what kind of volcanic. Volcanic eruption takes place, and that is viscosity, which is I can never keep it straight, but now I've got it. Viscosity is the ability to resist flow,

rightlid Right. If it's high viscosity, which means it has a high ability to resist flow, which means it's thick stuff, it's molasses. If it has a low ability to resist flow, meaning you're pouring something out of a cup and creating flow. If as a low ability, it's going to flow very easily and quickly out of it. So it's low viscosity. So viscosity and the amount of gas bubbles present are going to determine what kind of volcanic eruption you have. Right.

If it's high viscosity, which means it's very thick, then it will be a big eruption, right because it tried

very hard to get out exactly. And then the opposite is true if it's a low viscosity and the more gas is present, the more imagine just these little bubbles, the more little bubbles that are trying to get out, the higher the viscosity, the harder they're going to try to get out, and then when they do get out, kaboom, right, which is determined by how much silicon is in the magma, which I thought it was a little weird or not weird, but just I had no idea, So Chuck, we have.

Um when when it does go kaboom, that's called the eruption column, right, it's composed of hot gas ash pyroclastic rocks, which is lava in solid form. Right. Um. And that one, that one flow I was talking about Hawaii, the real slow kind of lumbering flow where's just bubbling over its effusive. Yeah, and that I mean that's not super dangerous because it's so slow, but it's still destructive eventually, Yeah, slowly destructive. If you're a plant that's stationary, you're in trouble because

plants can't walk at all. Let's talk about the different types of eruptions, man, Yeah, there's a bunch of these. Uh. My favorite is a Strombolian. It's definitely the most delicious for one reason and one reason alone. It's pretty impressive, not too dangerous. About fifty feet in the air. It's gonna be spewing a little short bursts, very highly viscous, so gas really has to build up in order for

this to happen. But they're pretty the small eruptions, not much lava going on, they make a big boom, yeah, a little ashy tefra, which is always nice in your volcanic eruption, right, and tefras that that fall in volcanic material. A lot of things like uh, undergo a change in name after they become after they've been a verb at some point, so like it goes from magma to lava to tefra. Yeah, right, and that's all rock or it depends. It could be asked, tefra is just any of the

material that comes out of volcano and is landed. Oh I thought you said originally it was all magma. That's well yeah, yeah, you're right, you're right, you're good, good chuck. Right. And then we also have the plenty in eruption, right, which the Yeah, this is the type of eruption that covered that came out of Mountain Vesuvius and I think and covered Herculaneum and Pompeii. Yeah, these are the big daddies that you think of when you think of volcano.

The big upward thrust, the thirty mile column of junk that is shooting out. That is the plenty in eruption, right yeah. I mean it's bad news for anyone around there, don't you think I would think so? Yeah, and not even right around there. I mean, like it can shoot pyroclastic material thirty miles into the air undred hundreds of feet per second. That's a big explosion. Um and uh so, I imagine I couldn't find it. Looked all over the place to find out what type of eruption the Iceland

volcano underwent in April. It couldn't find it. But this sounds a lot like a plenty in eruption. I mean, if they were shutting down air service in like southern Europe because of the ash that it entered the atmosphere. From this, it sounds like it was probably plenty allans I guess was to right, Yeah, basically all the ones you can rattle off off the top of your head, there's a probably plenty in volcan What about the Hawaiian

Those are the really slow effusive ones, right yeah. But they have like fire fountains, like they're cool to look at, yeah for sure, and it's cool sounding, yeah, And they can produce a lava lakes which are ponds of lava craters. Pretty cool. Yes, I've never been to Hawaii though, you know Strickland has, Oh yes he has. He loves talking about the Hawaiian eruptions ives butchering the Hawaiian names of things too. Are those other ones smaller and less frequent?

The the volcanian, hydro volcanic, and fissure. Yeah, the most common eruption types of the plenty in Hawaiian and Strombolian, and then less common like the real. Like, if you're an aficionado of of volcanoes, then you're gonna want to know about the volcano and hydro hydro volcanic and fisher. Like you said, the fisher has the curtain of fire. It occurs along like a a trench. It's not like a mountain. It's basically there's a tear in the earth and the the magma is becoming lava and like this

big curtain of fire. I can't really call it anything else in it be is dead on sure. The volcan ian is cool because of the pyroclastic bombs that it will shoot into the air, like football size bombs of of hot rock. This is the Earth being angry. The gods are awakening. Well, this is the other saying I'm

I'm moving around, dude. And then hydro volcanic compares a little um explaining this is a volcano that it takes place not underwater, but near water, near um, a very high humidity area, and basically the interaction of the water creates this chain reaction that turns the volcanic material into this fine ash right Um. It can also melt a lot of surrounding snow um, which can cause landslides and a lot of trouble for people. Yes, so those are the types of eruptions. Are you still awake and are

you still with this so far? Anyway? Right? People like, oh, yeah, the sun. Uh should we talk about the shapes or just the frequent the of eruption? Well, let's talk about the shapes, because there's there's the basically, there's three components to a volcano. Every volcano, right Um. You've got the magma chamber, which we talked about, it's where it builds up. You've got the central event, which is the the this

little connecting area, this is where it starts to. This is the fissure that it comes out of the crater, right you've got the summit crater, which is where it explodes out of right, and then um, you've got different types of volcanoes, three main shapes, and the strato volcanoes. So a strato volcano with a plenty in eruption is what everyone thinks of as a volcano, right, the classic what what you would build for your science school project

with the baking soda. That's a strato volcano. That's right. Unless you're a really forward thinking kid and you're like, I'm going to build a scory of tone volcano for extra points, which actually, if you did do that, you'd be pretty smart, because, um, while the strato volcano is the most familiar, the scory of cone volcano is the

most common. Yeah, I guess would be a very smart kid. Yes, And if there's any seventh graders out there looking for a cooler volcano, you want to add a little zing your volcano, make a scory of cone and say, Josh and Chuck, san't you and get prepared to be beaten fire classmates. Score of cones, by the way, if you need a little help, are Um, they're smaller, they're steep on both sides, um, and they're very wide right, uh, And they're usually composed of ashy tephra ashy telfra shield volcanoes,

that's the last kind. They're wide short, low viscosity dispersal of lava. So it's just a big using blob basically, and it builds up into like a shield like dome. And these these are repped like every few years, very frequent. So um, we'll talk about eruption a second. A good example of a shield volcanoes Mounta Looa, and a good example of a score of cone is Sunset Crater in Arizona. Yeah all right, Chuck, Josh, you ever heard of Crater Lake in Oregon? Yeah? Yeah, Gortis. Isn't there like a

down World War two plane or something in there? I don't know. Is that just like a cloud Cussler novel I'm thinking of? I have no idea. Well, Crater Lake was actually in extinct. We imagine an extinct volcano. Um Basically, the magma chamber blew it all at once, collapsed in on itself. The the crater collapses in on itself and it eventually fills in with water. It's called the caldera, yes, until it's full of water. Then it's called the lake.

That's right. Once again, add something, change the name. How many volcanoes are there active right now working in the world today, I'm gonna guess four. You would be off by about a hundred. What do you mean you're gonna guess you have the same information I do. Let's trying to mix it up. Uh, they are active volcanoes five hundred around the world. And the classifications a little inexact, even the revised classifications a little inexacutive. I didn't vers.

Here's why though. This is why it's inexact and subjective, because we don't have anything that won't melt if we try to really get a good look inside of a volcano. Yeah, so it's all just kind of like, well, yeah, it's smoking, so we're gonna call that an active volcano. The ones in uh, there was at least one when we were in Guatemala, remember, and then one went off right after Jerry was there? Really I think, so yeah, wow, yeah,

we'll find out after we stopped recording an ASCAR. So the classifications, even though it's inexact, we will quote them here if it's erupting obviously or or demonstrating some kind of activity within recorded history, right, then it's active. And why we say it's inaccurate because recorded history varies big time. Uh. If it is not showing any signs, but it has erupted with years, then uh it is you know, could potentially erupt again. So it's dormant, but it could could

go off. If it has not erupted in ten thousand years, then it's extinct, they say, right, but I say, all bets are off. Man, you never know. No, I agree wholeheartedly. I think, Um, if you're dealing with plate tectonics and um, there's clearly not any kind of magma chamber around that

we can detect, it probably is extinct. But as we said, they have revised the the rating of volcanoes, right, Um, so now if it's showing anything, is that what you just did was the revised version, because they really are similar to the original version. Basically. The only change is now if it's showing anything, then it's it's active. Right. Yeah. Weird, And uh here's the cool fact of the day. Right. Uh. And any given day, ten volcanoes are erupting. Yeah, that

aren't a big deal. Probably, well they are if you're staying next to Yeah, but it's not newsmakers, I would say. Yeah. And then one volcano is thought to have wiped out an entire civilization, Sanderini in Greece. Really yeah, the Minoan civilization suddenly disappeared, and they're starting to think that it was because they melted pretty much. Yeah, well, that's it

for volcanoes. If you want to see some really boss volcano pictures, I know where you can just type volcanoes into the search bar at how stuff works dot com. You've made it through this one. Pay yourself on the back. But hey, we've all got to understand volcanoes, right all right? So yeah, okay, since I said search bar, that means it's time for listener mail. So that is not only the end of volcanoes, Josh, that's the end of this is something else. Can you believe this? Can you believe?

I know you we're in the future like I thought. I thought it'd be in like spaceships and have pill meals that I could eat. I have pill meals in my pocket right now. Really, what you got? I have pot roasts and turkey and stuff. Did you add water and it becomes a big meal. You just eat it, you see, and it tastes like all that and get pulled up. So uh, you know, at the end of every year we like to say thanks. Obviously we're still on the air, and we wouldn't be if you guys

weren't listening. No, we would be, you know, just doing our regular thing right in the articles, crying ourselves, crying ourselves to sleep. Yeah, thank you for listening to all of you, a new people, all of you vets, all of you returning friends, everybody. Happy New Year to all of you very much. Um yeah, yeah, that's all I got. I mean, I I don't want to make a big deal out of it because I just want to keep on going through. Here's to the next year and eleven

months in eleven days left of earth? Yeah right, you want me to sing uh all anzig? Please? Can we get can we get Jerry to put it over? Or at leastly there's no rights on all at least Fogelberg's same old Anzig the Satas song in history. Oh that is a good one. Let's hear it shun oh no never, but I do have listen to mail. Well do you know an album that hear it on? Uh? The Innocent Age? Okay, So do you. Was it a good album? Yeah, I mean I actually owned that. I was a little kid.

I was like twelve listening to that song thinking it was sad when I was the wealth and that's Dan Fogelberg and uh it's what's the name, same old things on and what's the album The Innocent Age the Seas. So this is listener mail Josh from Kyle and this is about our our Chronica podcast which we got some pretty good marks from from our Jewish friends. Yeah, we

did here there, although I got good try. I had a few people that are are converted Jews say, hey, Chuck when he said it's not the same thing, that really hurt my feelings. I wasn't saying for you, it's not the same for me like I would I would feel like a I would still feel like a boy. So it's not the same for you. But in Chuck's opinion of you, it's the same. Yeah, that's that doesn't make you any less Jewish if you're if you've converted. I wasn't saying that at all. I was a kid.

I don't want to hur anyone's feelings. Hey, guys, great job on the Hanaka podcast. I'm a seventeen year old from De Plaine, Illinois. It's the home of the McDonald's Museum, right home of the first McDonald's. He says, I was raised atheists my whole life until the fourth grade, when I learned about religion, and as much as research a fourth grader can do, I decided I wanted to be Jewish. I love this guy in the fourth grade. He's like, I want to be Jewish. That's pretty cool, and he

did it. I realized that in college and I didn't do it. I ended up converting, being bar Mitzvoued, learned Hebrew, and now plan on joining the Israeli Army. Wow, I heard. I heard about this the real deal. I find it to be an amazing religion, and I loved your podcast on it. I just want to show you something you

might find interesting. None gimmal hey shin, which appear the dradle in almost every country in the world nska dol haya sham means a great miracle happened there, while in Israel the Dradel says none gimmal hey hey, which means a great miracle happened here. Cool. So in Israel they have a different radel because it's like could happened here and not there, as I've always found that interesting. Just want to let you in. Thanks for the podcast. And that is from Kyle the New Jew. I really think

Kyle was on MPR. I've heard an interview with somebody who had converted in the US and was now like going to Israel to join the Israeli army. Was a young guy like that? Yeah, he was young dude. It might be him. I wonder if it was, we'll have to check it out. That'd be pretty cool. Yeah, he should have come to us first, though, I agree whole hard at time, he's making the rounds of the media secure right hey, by the way, I mean that's what he's saying to everybody, right, Yeah, I was on stuff

you should know and MPR. Right, well, chuck again. Happy two thousand and eleven to you. Happy New Year. Congratulations sir on another year making it through another year with me having to deal with me. Hey, it's every year gets easier. Is gonna be a breeze? Nice? Um. If you have a New Year's resolution that you think is worth writing down and sending to us, you can also bring it up on Facebook. I'm sure there'll be plenty

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you by the reinvented two thousand twelve camera. It's ready, are you