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Volcanoes can be some of the worst natural disasters we can experience here on Earth, but life wouldn’t even exist without them. What are volcanoes good for anyway?
Show Notes
See the First Images NASA’s Juno Took As It Sailed by Ganymede (NASA)
VIDEO: The Daily Space 10 June 2021: Solar Systems Vary From Star Type to Star Type (CosmoQuest)
Flurry of photos capture China’s Zhurong rover on surface of Mars (Nature)
PHOTOS: Fissures, Lava Flow and Evacuations Continue On Hawaii’s Big Island (NPR)
What is the Mid-Atlantic Ridge? (Universe Today)
What is a hotspot volcano? (NOAA)
Active Volcanoes of Hawaii (USGS)
Soils from Volcanoes (UCSB)
Etna volcano (Volcano Discovery)
Nyiragongo volcano (Volcano Discovery)
Obsidian: Volcanic Glass (Geology In)
Obsidian (Mindat)
Topaz (Mindat)
Tourmaline (Mindat)
Zircon (Mindat)
Granite (Geology.com)
Plate Tectonics (National Geographic)
Earthquakes and the Earth’s internal structure (AMNH)
Eruption on Iceland’s Reykjanes Peninsula 2021: activity updates (Volcano Discovery)
Chasing Magma Around Iceland’s Reykjanes Peninsula (Eos)
NASA’s InSight Detects Two Sizable Quakes on Mars (NASA)
GPS Data (USGS)
Volcanoes on Mars Could Be Active, Raise Possibility of Recent Habitable Conditions (PSI)
What is a hydrothermal vent? (NOAA)
Paleomagnetism For Rookies-Part One (JOIDES Resolution)
Are we about to have a magnetic reversal? (USGS)
VIDEO: Astronomy Cast Episode 588: Lunar Resources: Lava Tubes
Geothermal Electricity Production Basics (NREL)
Manitou (Colorado) Cliff Dwellings
NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus (NASA)
ESA selects revolutionary Venus mission EnVision (ESA)
Volcanism on Venus (SDSU)
Researchers Discover What May Be 37 Active Volcanoes on Venus (Smithsonian Magazine)
Volcanic “pancake” domes in Tinatin Planitia, Venus (NASA)
This is our best look yet at the solar system’s most volcanic object (National Geographic)
Enceladus: Ocean Moon (NASA)
Transcript
Transcriptions provided by GMR Transcription Services
Fraser: Astronomy Cast, Episode 609, The Benefits of Volcanoes. Welcome to Astronomy Cast, your weekly facts-based journey through the cosmos where we help you understand not only what we know but how we know what we know. I’m Fraser Cain, publisher of Universe Today. With me as always is. Dr. Pamela Gay, a senior scientist for the Planetary Science Institute and the director of CosmoQuest. Hey, Pamela, how you doing?
Dr. Gay: I am doing well. It is glorious summer weather here, which means it isn’t good for observing because you will be carried away by the mosquitos before you get good data, but it also means we have four episodes before summer hiatus this year.
Fraser: That’s true. Two things that I think are really important right now that people should be aware of, one, Juno sent back new pictures of Ganymede, and they are stunning, the first time we’ve seen close up pictures of Ganymede since Galileo. They’re amazing.
Dr. Gay: Actually, I found out from one of the team scientists that Galileo’s data wasn’t as good as Voyager’s. So, this is the first time we’ve gotten data this good since Voyager.
Fraser: Oh, wow.
Dr. Gay: So, it’s amazing. And I learned something new looking at those images, and then talking with Candice Hansen. Did you notice how the craters have divots in the center?
Fraser: Yeah.
Dr. Gay: So, it’s a form of terracing that you get when you’re going into ice.
Fraser: That’s what I was wondering. The craters all have this weird look, and that’s because the asteroids are impacting ice, not rock. Wow, okay, amazing. We were actually wondering about that. That’s so cool. The second thing is we’ve got some new pictures of the Chinese Zhurong rover, which has been sent back. And it’s so adorable. And it’s so cool to see these pictures as well. So…
Dr. Gay: And it has something that I haven’t seen before. It has curved solar panels. So, it looks like it has butterfly wings instead of just your normal flat shelled rover.
Fraser: Is that to shed the dust a little easier?
Dr. Gay: I haven’t figured out why yet. I just saw that in the image, and now I need to go spelunking through the Internet to see what I can find out.
Fraser: Oh, that’s really cool. Now, volcanoes can be some of the worst natural disasters that we can experience here on Earth, but life wouldn’t even exist without them. So, what are volcanoes good for anyway? Pamela, now you famously love supervolcano events, volcanic disasters of all kinds. And so, obviously, the thing that volcanoes are good for is to entertain you as they destroy vast landscapes on planet Earth. Aside from that, what are they good for?
Dr. Gay: Oh, let me count the ways. Now, I do wanna say, I don’t like it when the volcanoes take people and buildings out. While, I was amused to see fissures opening out in people’s backyards, it was amused in a, I really hope they have good insurance kind of way. So, I’m a fan of the power of our planet’s geology, not of destruction of humanity.
Fraser: To just be clear, you’re not a supervillain. You’re merely a fan of the marvels of nature.
Dr. Gay: Exactly. So, volcanoes – Iceland is really the place to look to find some of the coolest examples of what they can do. First of all, they just add land. The nation of Iceland is straddling the mid-Atlantic rift. It is getting torn in half. It is also on top of a hotspot. And over the millennia, as the island nation gets torn in half, you don’t actually see a gap forming because all the volcanism there is just filling it in.
Now, the other side of this is there are islands all around the world, the Hawaiian islands are one of the most noticeable, where you have a chain of islands that on one end is all dead volcanoes that are well weathered over time and are a great place to go live, and then you have – as you move down the chain, you have younger and younger islands that are more and more mountainous, more and more active. And these islands, which are still growing for the active ones, have amazing land to farm. And if you want a nation to grow, well, this is a different way to do it.
Fraser: And I mean, a lot of the volcanic islands like the Hawaiians that you mentioned, even just across the whole Pacific, there’s tons of these islands. They provide stopping off points for birds that are migrating, various sea creatures. And as you said, the land around a volcano is incredibly fertile. We’ve known this back since the Greeks and the Romans, keep settling on Mount Etna. Why? Why are volcanoes so fertile?
Dr. Gay: Well, they’re bringing up a bunch of different minerals from deep in our world. And it turns out that when you leave soil on the surface of the planet, and you let plants grow in it long enough, those plants are gonna use up the minerals in the land. And they have to come from somewhere. Now, we can fertilize land, putting back our own biomass in the minerals that our body has decided to get rid of in different kinds of ways. But volcanic ash is a naturally spread out form of fertilizer that a nice friendly volcano that hopefully didn’t just destroy your village is capable of throwing up into the atmosphere.
Gravity brings it back down, scatters it in layers, which are annoying if you’re trying to walk, but great if you’re a plant looking to absorb it. And it’s this bringing the nutrients out from lower levels of the planet that allows our planet to constantly have rich places to grow new fruits, vegetables, trees, and everything else.
Fraser: And you get this situation. I mentioned Mount Etna. You get the situation where you have these really fertile areas because of the ash, because of the lava that’s been laid down, and people keep attempting to live there. And the keep living really close to a dangerous volcano, which can sometimes end badly.
Dr. Gay: And this is currently something that is being struggled with in the Congo area because they have a giant volcano that I’m not going to mispronounce, that is near a fairly large city and has been eating out part of the city as it covers it in lava. And this particular volcano has extremely runny lava that doesn’t have a lot of silicate in it. So, while some volcanoes, you can outrun the magma as it heads towards you, this one, it’s going more like 60 miles per hour.
Fraser: Oh, wow.
Dr. Gay: And you can’t outrun that. But the land is good to grow in, so they keep going back.
Fraser: And you’re just gonna get this cycle again and again. So, we know that wherever there’s a volcano, you’re going to get fairly nice material, nice, new growing material laid out. What else, what other value do volcanoes bring to life and just the planet?
Dr. Gay: Well, for humans, you have an actual value. In association with volcanoes, or as it gets put by geologists, extrusive rock, you end up with some of the most beautiful minerals. Volcanic glass is nicely named. You know exactly where it came from, but in addition to the volcanic glass, you have all different kinds, colors, and textures of obsidian that all come from volcanoes and get used to make all sorts of amazing jewelry and sculptures. So, there is literal value in those rocks.
Fraser: So, some of the precious gems that we think of, I forget which some of them are, they have to go twice – well, sometimes it’s once through the volcano. Sometimes, it’s twice through the volcano, right?
Dr. Gay: So, that I have to admit is beyond what my astronomer’s brain knows.
Fraser: Oh, sure.
Dr. Gay: But we have things like topaz, and tourmaline, and zircon. These are all associated with volcanic rock, igneous rock in this case. And so, you get beautiful obsidians. You get various gemstones. There are times when you actually get diamonds, and peridot, and all these beautiful colored stones that get turned into jewelry, all associated with volcanism.
Fraser: Another one is granite. Granite is a volcanic rock that – in igneous, a type of igneous rock. And so –
Dr. Gay: It’s what you get when the lava cools very slowly. So, it’s weird. You get different things depending on – well, first of all, what part of inside the Earth did the lava come from? How quickly or slowly did it cool? What was its consistency? And this is where you get geology students who sometime, as part of their PhD, mix things together, heat them up, and see what happens.
Fraser: We know that volcanoes give us lots of minerals, help us grow our food, help provide all kinds of biodiversity on planet Earth, but how do scientists use them to understand the Earth?
Dr. Gay: So, the volcanoes themselves are part of amazing networks. So, depending on which ones we’re dealing with, we use them in different ways. We find them where the plates of the Earth pull apart. We find them where the plates of the Earth are diving underneath one another. And in these different situations, the movement of the magma beneath the surface of the Earth will trigger little tiny earthquakes, hopefully, occasionally bigger earthquakes, unfortunately. And all of these waves passing through the ground allow us to map out underground structures.
There’s recently been some really cool work done in Iceland, where with the new volcano that’s going off near Reykjavik, there were massive numbers of earthquakes, sometimes a hundred an hour or more leading up to that eruption. And where the earthquakes were centered changed over time as the magma cavity expanded, as the magma was on the move. And now, thanks to all these little, tiny magma-induced earthquakes, they have been able to map out all that underground plumbing associated with a bunch of the different volcanic areas in that part of Iceland.
And they’d already mapped out other parts. And system by system, earthquake by earthquake, volcanic eruption after volcanic eruption, we are able to figure out what’s under the ground where we otherwise can’t see it.
Fraser: It’s an amazing thought. I mean, hilariously, we’ve got a similar situation happening over on Mars with the InSight spacecraft, which is sitting on Mars, and it’s measuring these little earthquakes. And it’s using these to help scientists to try to figure out the geology of the area around the InSight probe. But here on Earth, these astronomers – oh, sorry, these geologists, they set up the seismometers around the volcano. And each time they have one of these earthquakes go off, it’s like this little probe they pinged into the – below the ground to start to sense a little bit.
And over time, they build this incredible map of what’s going on underneath our feet. And it’s like – I remember, we were in Hawaii, and they were saying – some that are just – that lava is moving, causes the earthquake. Crazy.
Dr. Gay: And what’s amazing is there are now indications that within tens of thousands of years ago, there was active volcanism on Mars. And it’s thought because that volcanism appears in the same region on Mars, that InSight is sensing larger earthquakes, that there may still be not active volcanoes, but perhaps magma that still hasn’t fully solidified, that is triggering some of those earthquakes. So, this is how we map things, one earthquake at a time.
Fraser: Now, volcanoes will sort of leave behind wreckage of their eruptions, in some cases, showing different layers of rock, and sediment, and things like that. So, how do geologists use volcanoes and the lava coming out of volcanoes as a way to perform other science experiments?
Dr. Gay: Well, so we don’t use them for a lot of additional science experiments other than when we’re trying to simulate Mars environments, but we can look at the lava and know by how it weathers over time from the rains and other seasonal conditions, how old an area might be. We can use it to get a sense of what is the composition of the planet on the inside in different place, where different volcanoes are erupting with different mineral signatures, literally bringing us samples from deep inside the Earth. And then, we also use them to do science related to the origins of life.
It is thought by many people that life may have originated either in ice or around hot thermal vents. And if it’s hot thermal vents, it could have been deep in the ocean in conditions that exist not just on Earth but on moon after moon and dwarf world after dwarf world throughout our solar system.
Fraser: That’s one of the other things that I find the most amazing is this idea of paleomagnetism.
Dr. Gay: That is something I have to admit, I always forget about because it’s cool, it’s just not my jam. I get distracted by life because you’re looking at the same hydrothermal vents in both cases. In the deep oceans, there are places where the plates of the Earth are pulling apart, and you have volcano, after volcano, after volcano lined up across the ocean floor. And over the eons, as the lava has come out, it contains magnetic materials, iron in it. And as it cools, those minerals line up with the Earth’s magnetic field.
Now, our planet’s magnetic field changes over time. And as thing divide, as the lava moves further and further apart, we see essentially fossilized into the rock, the Earth’s past magnetic field. Now, we can do this on land as well. There’s just not as many really good places to go and see eons of lava spread out, but there are some examples. So, we see how our Earth’s magnetic field has changed by looking at how lava has solidified over the years.
Fraser: Yeah, we know pretty much exactly the last time the Earth’s magnetic field was reversed. And sort of – and people are able to actually start to track what happened during the time when the reversal was occurring. It’s a stunning piece of science. We’re due for reversal, by the way, but don’t panic. It’ll probably be fine. Now, we did a whole show on the advantages of lava tubes, but let’s give a quick – just a quick sort of reminder of that feature.
Dr. Gay: So, one of the problems we deal with is our sun as well as other objects throughout the galaxy and the universe beyond like to fling high energy particles. And if you don’t have a planet with a strong magnetic field, those high energy particles just might try to kill you, either quickly or slowly. I’m not sure which is better.
Fraser: Neither?
Dr. Gay: One way to avoid both these fates is to protect yourself from the high energy particles, which you can do by surrounding yourself with water or surrounding yourself with rock. And lava builds nice friendly, we hope, places where humans can live underground, on the moon, on Mars, and other places throughout the solar system. Now, there are issues. Lava tubes are sharp. They’re not well weathered. And on Mars, we don’t know what’s inside them. And when I say this, I mean, there are folks thinking it might be a good place to go looking for life, and we probably don’t wanna put ourselves someplace that is already occupied, no matter how small the occupants may be.
So, there’s this glorious hope of someday living, working, building habitats inside these naturally protected from radiation places. And there is hopes to someday go looking for life in some of these on Mars, hollows beneath the soil where there’s a chance that heat stayed over time. We actually use volcanic areas for hydrothermal electricity here on Earth, and heating water, and heating homes. And there may still be warmth in the depths of Mars and places where life continues to thrive, protected from radiation, warmed up, and waiting for us to come and find it.
Fraser: And also, as we mentioned in that other episode as well, they’re great places to go and search for life, places that are protected from the harsh environment of space, both – I mean, the moon, who knows, but Mars –
Dr. Gay: I don’t think we’re gonna find life there.
Fraser: Yeah.
Dr. Gay: But Mars, yeah.
Fraser: But Mars, more likely. But also, they’re good places – they’re just better protected places just for humans to set up as well.
Dr. Gay: And they’re prebuilt structures. Looking back at the history of humanity on our world, we know that over time, people have over and over again, lived in caves just because they’re there, and it makes it easy. From the cliff dwellers of Colorado, the Anasazi people, to early people, there’s amazing art scattered all throughout caves in Europe, all these different places. These are natural structures, and there are places where people continue to live in caves, to dig into the sides of hills because it’s thermally so much better protected.
You don’t have to insulate your house nearly the same way if you just build in a hill hobbit style. So, why not do I ton another world?
Fraser: And on some of those other worlds, they can be – with a third of the gravity, you can have vastly larger lava tubes on Mars. With ⅙ the gravity, you can have potentially hundreds of meters, even perhaps kilometers high lava tubes on the moon.
Dr. Gay: And that starts to be all you need to get a civilization started somewhere else. Seal it off, mud the walls, add a bunch of plants, and start up society on backup.
Fraser: So, when we’re recording this, NASA announced they picked the two vehicles as part of their Discovery program. They’re going to send two spacecraft to Venus. Now, obviously –
Dr. Gay: And ESA said they’re sending EnVision to Venus as well.
Fraser: And we still don’t know if there are volcanoes on Venus, any kind of active volcanism. There’s a slight hint maybe, but hopefully we’ll be able to find out if there’s volcanoes on Venus.
Dr. Gay: And the question isn’t as much, are there volcanoes at all, but how recently were there volcanoes that may have erupted? And so, just like we don’t volcanism today on Mars, but we’re seeing that there – may have been there 50,000 years ago, how recent was there volcanism on Venus? We may learn in the next few decades.
Fraser: And unfortunately, the terrible price that we had to pay for getting two missions to Venus was no missions to Io, which is the most volcanic place in the entire solar system. And what kind of a scientific volcanic boon do you think we would get from being able to examine Io?
Dr. Gay: Oh, I can’t even begin to guess the vastness of creativity that scientists have come up with for all the reasons they want to go. Luckily, JunoCam because of the orbit the Juno mission is on, will get some fairly close approaches to Io. Not soon, but they’re in the mission plans. So, we will at least get better images than we’ve had before. And what gets me about this is it gives us a chance to see how lava interacts essentially with the vacuum of space, this idea of volcanoes that erupt up into the surrounding space of a world.
With Enceladus, we saw geysers that added to the rings of Saturn. Well, with Io, we have volcanoes that spew fountains that we can see from far distances, hundreds, thousands of kilometers away. Just understanding that interaction is something that I for one really wanna see.
Fraser: And so, I – thanks, volcanoes, for helping reveal, I guess, the interior of the places that you form, both the rock volcanoes here on Earth, the ones that are gonna be on Io, perhaps even the cryovolcanism that we may see in worlds like Europa, Enceladus. You’re taking stuff that was hidden and throwing it out on the surface for scientists to scrabble through and see if they can learn any new insights. It’s much appreciated.
Dr. Gay: And life. Thank you for the life and the shinnies.
Fraser: Thank you for –
Dr. Gay: And the shinnies.
Fraser: Thank you for the life and the shinnies. And thank you, Pamela.
Dr. Gay: Thank you, Fraser.
Fraser: Do you have some names for us this week?
Dr. Gay: I do. So, this week, I’m gonna whip through a ton of names because we don’t have that many episodes left before we go to summer hiatus. We’re gonna be working our butts off through the summer so that when we come back in September, you’re hopefully gonna have a much higher media quality product, where we’re gonna be able to show you images of the things that we’re talking about during these episodes. To make all that happen, we need your help. Your donations are going to allow us to use our summer to improve the quality of the next season of this show.
Now, I’m gonna read a ton of names for the people who have already said yes, I’m going to help. And we are so grateful to all these people.
I wanna thank Mark Phillips, john öiseth, Bob the cat, Jeff Willson, Jim McGihon, Ruben McCarthy, Geoff MacDonald, Wayne Johnson, Iggy Hammick, Kevin Lyle, Catherine McCabe, Jordan Young, Burry Gowen, Birko Roland, Jeanette Wink, Aurora Lipper, Joe Hook, David, Gerhard Schwarzer, Andrew Peolstra, David Truog, Brian Cagle, Robwer Wenger, TheGiantNothing, Venkatesh Chary, Jean-François Rajotte, Ben Lieberman, William Baker. Laura Kittleson, Robert Palsma, Joe Hollstein, William, Jos Cunningham, Paul Jarman, Les Howard, Emily Patterson, Adam Annis-Brown, cacoseraph, Just Joe, Ed of the Universe, Helge Bjørkhaug, Matt, Nicole, Vorisek, Bill Hamilton, Gordon Dewis, Frank Tippen, Joshua Pierson, Jack Mudge, and Alexis.
Thank you all so much. You let us do what we do.
Fraser: Thank you, everybody, and we will see you all next week.
Dr. Gay: Bye-bye.
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