Hello and welcome to the Physics World Stories podcast. I'm Andrew Lester, and in this episode we're going to be exploring Pele's hair and Pele's tears. These extraordinary wave structures formed by volcanic eruptions can help us understand the dynamics of those eruptions. Atmospheric processes and planetary geology here on Earth, and quite possibly out there in the solar system.
And there are plenty of tales of derring do, including exploring the depths of the ocean, volcanoes in submarine, because we'll hear from two people who spent their careers so far studying volcanoes soon we'll hear from Tamsin Mather of the University of Oxford. But first, I wanted to know why the name Pele in Pele's and Pele's tears came from and in case you're wondering, it's nothing to do with the footballer. Here's Kenna Rubin, who spent 30 years as a volcanologist on the island of Hawaii.
Pele is volcano goddess in Hawaii and interestingly enough, she resize or is thought to reside underneath Kilauea volcano. And, you know, a little bit just to inject a tiny bit of Polynesian history here. There were various waves of migration of Hawaiians or the people that populated the Hawaiian Islands, first from the areas that, we now know or of as French Polynesia and Marcos's in Tahiti, and they brought various Polynesian gods with them in the volcano.
God that they brought was named Isla out and Isla and was, very, sort of waterfall God, a God who was subject to fits of temper. And in fact, scientists at the Hawaii Volcanoes have correlated this observation and personification of Isla out with a phase of explosive volcanism. A Kilauea volcano which ended in the 1790s, and Pele was brought to Hawaii as a concept by Samoans that started to migrate to the islands maybe 3 or 400 years later.
There are many, of the Davies in the Polynesian religion which are similar across the islands. Pele's one who is different. And so when Pele came to the islands, she took on a somewhat different vibe. Pele is, also, known to be a vengeful god. She lusted after many men. And then after, enjoying relations with those men, she would oftentimes turn them into features of the landscapes. There are many volcanic features on all of the islands are named after people that Pele supposedly turned into.
These features, for one reason or another, and her arrival in the Hawaiian Islands is thought to coincide with the transition to a more, subdued, lava flow, what we call effusive volcanic style. Just a little tidbit. The 2011, excuse me, 2018 eruption at Kilauea on the, eastern south southeast rift zone that erupted in the neighborhood. If you recall, it was the Leilani Estates eruption.
Some people thought that that was a return or resurgence of either out because of the violence of the eruption, as well as the collapse of the volcanic caldera that was happening up at the summit of the volcano. That hasn't necessarily been borne out in the subsequent, activity.
But this is this is something that, very important to the people in Hawaii is, personifying processes not just in the volcanoes, but up in the atmosphere, different states of weather, the who controls the wind in the waves and the coral reefs with the deities.
And so I say that because while it's important to respect everyone's cultural perspectives and their religions, it also gives us an important way of understanding the way Hawaiians interact with their natural landscape, the renewal of the land that happens because of volcanic phenomena, and the instability of the land because of the volcano. We'll hear much more from kind of later in the podcast, including her adventures exploring underwater volcanoes.
But first, let's go to Tamsin Mae, the professor of earth sciences at the University of Oxford. For more than 20 years now, I've been studying the world's volcanoes. I guess some of the highlights are going out there and, and seeing volcanoes in the wild, so to speak.
So standing next to fire fountains on Mount Etna in Italy, down in Sicily, staring into massive, roiling lava lake, going to Hawaii and, and studying the, emissions coming out to the hello mama crater, hiking down into the jungle in Guatemala to sample rocks. That's just a few amazing Pele's hair and Pele's tears. Oh, they're really extraordinary rocks. Actually, they really, really do look like, hair.
When you have a basaltic lava lake or lava event or lava flow with bubbles bursting on its surface, when the the bubbles break, they can kind of, extrude and stretch, the glassy rock. So the magma, freezes and forms glassy threads, which then blow up or waft up with the volcano's hot gases, and get deposited on the ground or caught in fences or on, on ridges and vegetation around the volcano.
And it looks just like from a distance, looks pretty much like kind of animal hair, like dark sheep's hair or something like that, caught on a fence. But then when you pick it up, it's brittle, and glassy and actually can be quite sharp and you can get it stuck in your fingers and things. So it's really extraordinary stuff. That is a away you have, they sit, they, they fly out and you have the, the droplets from the top of bubbles bursting.
So if you ever looked at, a slo mo of a water bubble bursting, sometimes you get a drop at the top. So sometimes they're formed like that, and then sometimes they're just the sort of more gloopy end of the, of the extrusion. So you actually get a Pele's hair, which terminates in a police tear, and they are exactly as they sound. The that shaped glassy blobs, that then, pretty small, and then get wafted up with the volcanic gases. So they must be cooling very quickly then. Yes.
Particularly the glass shards, because they're so fine and thin. They have a very high aspect ratio. They call really, really quickly. And that's why you get glass rather than having many crystals forming in them. Okay. But if you were sort of walking along, not that you'd want to be while this was going on right now, I assume. But if you were walking along in this sort of did get in your hair, that would be problematic.
I the worst place it could be in your eyes because, as I say, these, these glassy shards that if you rubbed your eyes, you might break them and you get sharp. But since you're into your eyeball, which would be, I'd imagine, deeply unpleasant. Fortunately, it hasn't happened to me as yet. Okay, but imagine the tears are quite if one of those struck you as it had been blasted out of a volcano, that would hurt quite a bit. They're pretty small, and actually, not that they're not that heavy.
They're quite light. So, that's not too much raw. Okay. So enough. But what you can do with them is pick them up, take them back to the lab and study them. Yes. So the great thing, I mean, utterly beautiful and amazing. Wonderful. And fascinating. But the great thing, as well as because they've quenched so they've cool really, really quickly. And you've got this glossiness, it means you've, you've got a, kind of, you've got a total composition, if you like.
It hasn't separated off into the different crystal phases. So you can just crush it up, or probe it with, with a different beam technology. And you can get the composition of the glass that was there in the lava, like, you know, pretty much as you walk past. So, so that's a real advantage to them. You know, you kind of know the, you know, that they, they don't persist for long, long periods of time in the environments. You know, that they've just been there probably a few weeks at maximum.
And if you clear a surface and then collect some more of them, you know, that that's really fresh stuff. So you know, that of representative of the magma composition there and then in the lava lake or on the lava flow. But what does that tell us, knowing that kind of composition? So, a bunch of different things, really. So one of the things we might be interested in is the fluid properties of the magma. So, how viscosity is, how sticky it is.
So one of the things we want to know about for that would be the, the silica content. So silica and oxygen, because silica shouldn't form polymers in the magma. So the more silica an oxygen you have, the stickier a magma tends to be. So the lower that is, the runny and magmas are if it's getting stickier, then that might change the way that the dynamics of the lava flows or the eruption might go.
You might also want to look at things like dissolved water content, because that also affects how sticky a business of my flour is. And also the dissolved water content, determines how volatile, how volatile rich the magma is and how explosive it might or might not be. So if you, for example, looking, at a long lived lava lake like in Hawaii, you might be interested in how these different parameters are changing with time.
And that might also give you clues about what's going on deep inside the volcano. How often would you be finding them? How often do these conditions arise? It's hard to say how often this I mean, this is quite specific set of conditions. You need a dynamic, lava or magma, interface with bubbles bursting or that you need the, the, the the magma to be low enough viscosity that you can get this extrusions happening.
So it's not you know, it's certainly in my career, I've been in this situation sort of 3 or 4 times where that being said, if Pele's had deposits around, so it's not it's not super rare, but it's also not something you necessarily expect every single time you go to a volcano. So all of the volcanoes that you've looked at are on land. Most of the world's volcanoes are underwater, most of them at the mid-ocean ridges, but those are pretty deep under the waves. They're quite hard to study.
I certainly studied some, some shallow submarine volcanoes. I believe that people have found Pele's hair in submarine volcanoes, but I've never studied that myself. When you set off to go to a volcano, you're looking for specific things. Or you just like, let's go and find out what's going on there.
Well, I mean, I go to volcanoes for a number of different reasons, but probably the times that I've been and collected Pele's hair as well is when I've been studying the gas emissions from the volcanoes. And I want to understand how much of the different components are coming out. And sometimes that might be the major gas species, like water, carbon dioxide, sulfur dioxide.
And then we might be wanting to see think about what we can tell in terms of what those gases tell us about the subterranean plumbing of the volcano and its status in terms of hazard. But other times I'm thinking about the environmental impact of volcanoes. So I'm interested in all sorts of different elements coming out, all sorts of, different metal species coming out.
One of the interesting things there is if we, if we measure the metal, species, metal, chemical, chemical species, if I did the plumes, the different salts and and things like that. You're interested to find out how that compares to their concentrations in the magma? Because what you'd like to understand is how volatile the different metals are. So how easily they are transferred from the magma to the gas phase.
Because if we can understand more about what that means, we can make predictions about how it might behave under volcanoes based on just a lava sample or, or a glass sample. So we're not we're not always there yet, but that's the sort of aspiration we'd like to understand more about that degassing process of, of different elements in the periodic table. So that's somewhere where I might be very excited to find some place that's going to tell me about the magma in the, in the, in the magma event.
Right at the moment, pretty much that I'm measuring the gases sitting on the edge of the volcano. Different, different chemicals are cycled through our planet in natural cycles and different ways. Volcanoes are part of that in terms of providing a conduit for different chemicals between the solid Earth and the environment on the atmosphere. So we'd like to understand how it's operating today so that we can think about how it might have varied over geological time.
Is that something that would inform our understanding of climate change? More broadly, yes. I mean, the carbon dioxide and sulfur dioxide are a major, major sort of, climate, elements. So we are interested in how volcanoes are forced climate back in geological time, because sometimes that gives us clues in terms of the sort of massive carbon release experiment that we're currently undertaking as a species, the consequences thereof. Volcanoes have released, a lot of carbon.
So big events and volcanic past these things called large igneous provinces. So if you go to somewhere like the Deccan in India, actually we've got some here in the UK, if you go to northern sky, you can see these big stacks of basaltic lava flows. And these are the remnants of, of large igneous provinces. And these are these enormous outpourings of largely basaltic magma onto the surface of the planet. And they last about a million years.
But they put about 1,000,000km³ of magma onto the surface of the Earth. So just one cubic km of magma would cover the whole of Greater London to about 60cm. So this is we're putting millions of these out. They cover big areas in places like Siberia. The Columbia River in not in North America, for example. So during these logic, these provinces that sort of doubled the rate of volcanism on our planet and doubled the rate of carbon dioxide being put out by the world's volcanoes on our planet.
So we're interested to see what the environmental consequences of that are, because right at the moment, we're doing even more than that. You know, we're we're we're doing 60 times the amount of carbon dioxide that comes out of the world's volcanoes. So, you know, we're beating the logic. These provinces, we've been at this a much shorter length of time. We've only been at it for a couple of centuries.
But, you know, so far we're we're best in class at carbon dioxide emissions compared to volcanoes. And and so we are we're interested to study, understand how much carbon came out, which is where sitting in volcanic plumes today is of interest. And and also just the consequences. And, we see some pretty strong consequences. We see, we see mass extinction events associated with these large igneous provinces. We see episodes of global ocean anoxia.
So when all the oxygen in the oceans got depleted and you get these black shale layers and the geological record of, of oxygen depleted, of oxygen, diagnostic of oxygen depletion in the oceans, for example. So, so that's why it's a sort of interesting comparison to understand the environmental impacts of volcanoes. It's not the only way to understand what we're doing, what what our consequences are as a geological force, by any means. But it's one of the ways that we might go after that.
What is it that attracted you to to this area of study? Well, so I did a chemistry degree and, and then had a couple of years at science and decided I wanted to go back to doing science. I would do I didn't just want to be in the lab. I liked lab work, but I also wanted to be outdoors and sampling the world and kind of understanding large scale processes, as well as the sort of what was going on in, in a test tube or even smaller.
And so I was looking around at environmental chemistry projects, and I happened to find this one, on the, the atmospheric chemistry of volcanic plumes. And I'd done some specialist modules in atmospheric chemistry, so I thought I might be able to give that one a go. And, the rest is history. As I say, I think the study of Pele's hair is part of a wider projects in volcanology. I mean, there are there are papers written specifically on Pele's hair, talky Pele's tears.
It talks about the shapes, cataloging the shapes, looking at, the singularity. This is a bubble structure within the Pele's tears. And talk about how those relate to things like the viscosity of magmas, for sure. But, but for me, I think, they are really interesting as part of our wider endeavor to really understand volcanic processes, both looking, peering in and looking down and thinking deeper into the earth, but also, looking outwards and thinking about the consequences of volcanoes.
So the other piece of the puzzle, they tell us another piece of, information, other pieces of information that we can build into bigger pictures. It seems like it would be a slightly treacherous, way to spend your time studying volcanoes, if you had any particularly hairy adventure, Harry. No pun intended. Well, it was it was intended. Fortunately, not too much. I mean, I've certainly been scared of the volcano. I think it's right to be a bit scared.
Your your, you know, your high alert. You should be. You're on a an unpredictable, natural phenomenon. I do try to be very, very careful. I, I am not, I do not take risks for the sake of taking risks. I, very, very adamant that no measurement is worth taking undue risk for. We always talk very carefully to the local scientists who are monitoring the volcano. Now, not all volcanoes worldwide, are perfectly monitored. Or or even well monitored.
So sometimes you do have to take a bit of a risk. But. Yeah. Just to get me to give you an example. So, Santi, due to volcano in Guatemala, which is where we were hiking down into the jungle to do some play, it was a bit frightening because the volcano has, you know, small, smallish, but still sizable explosion. About every 45 minutes. So you'll go down the jungle, there's this volcanic, cone above you. Boom. Every 45 minutes. Pyroclastic flows come down the side of it.
Now, we'd looked at the map, so we talked to the local scientists. We need the pyroclastic flows basically went down into a big, big valley and went off a different direction. But when you're underneath a volcano, you can't see that. You just see the power tastic flame coming towards you. And, you know, just hoping it's not going to appear up the other side of the, of the other sides of the valley. And it didn't, we sampled our rocks and and hiked out again. But, but yeah, it is.
They are you must we it is really important to respect the the volcanoes and to be as careful as you possibly can. How long is the risk assessment? Yeah, well, it could run to several, many pages. Normally had some very detailed maps and lots of notes of contact numbers. I wanted to know more about these underwater volcanoes and the possibilities and realities of exploring them. Kind of.
Reuben is a professor at an associate dean for research at the Graduate School for oceanography at the University of Rhode Island. So in my current position, I am responsible for the research portfolio of a school of oceanography that means shepherding programs and projects, managing our ship and shore based facilities, managing our research personnel. I also have about a third of my job. The still dedicated to research. My research is in volcanology and oceanography.
I moved to the University of Rhode Island two years ago, from a 30 year career as a professor at the University of Hawaii in, the Department of Earth Sciences, where I spent a great deal of time studying both Hawaiian volcanism and my particular specialty, which is submarine volcanism, including the deepest known active volcanic spots under the sea on the planet, on the volcano side. Who doesn't love volcanoes? They're spectacular. They're awesome.
They are, fascinating to study, I guess, understanding how they function. For me, I'm especially interested in how they erupt, how often they erupt, how eruptions impact the environment, how they impact ecosystems. And that's part of my interest in both. So the aerial meaning above water and submarine, which is underwater eruptions. My love of the ocean started from a very, very young age. I've always enjoyed the sea, studying it, being in it, being around it, being able to see it.
And so, I have a merger of those two things. It's been a wonderful, an exceptional career. I've had more than 30 expeditions at sea. I've had more than, 60 dives in, human occupied submersible, another several hundred in remotely operated vehicles and one of the things that few of us who study submarine, volcanoes, it's a relatively small community, but few of the other folks who do this kind of work also have experience, working on volcanoes, on land.
So for me, seeing what happens on land and understanding which which features are similar, which features are not, and how the, increasing depth as we go down further from the surface, under the ocean affects volcanic processes to some extent. It doesn't affect them at all. To other extents, it affects them very greatly.
And this is something that is interesting not only for studying the range of volcanism on the planet, but also understanding how volcanism might happen on other planetary bodies, such as Venus, whose atmospheric pressure is very similar to what we find in relatively deep submarine settings on Earth. Okay, going in submersibles and looking at underwater volcanoes, I mean, that sounds like something James Cameron would want to do. He and he has done it.
And so most of my work, especially my deep diving work below about two kilometers, has happened with, Woods Hole Oceanographic Institution using their vehicle. Alvin. In fact, we just published an article last week in EOS, the American Geophysical Union's weekly news magazine, about the recent deep diving upgrade to the vehicle. We can now take it to 6500m depth, which is, you know, more than 20,000ft for those who still use the imperial system.
And on one of the dives on that program, I discovered what we now know is the deepest on Earth, submarine volcanic deposit, about 60 100m depth in the Mid Cayman Rise.
And what's fascinating is, is that even though the very high hydrostatic pressure, the pressure from the weight of all that water pressing down on such a deep, seabed location, one would think would have that would affect the evolution of volatiles or gases that become unresolved from magmas and drive a lot of eruption processes, including Pele's hairs. But to some extent, those phenomena happen even at those very great depths.
And this is one of the things is so interest ING about getting to make these observations in those locations. Can you just sort of describe that experience to me, of being in one of those submersibles and arriving at the volcano here? It's it's not for everyone. So, in fact, it is a two meters here in about, a third of that sphere in the horizontal direction is filled up with equipment.
And then you sort of, you know, you sit on your side or lie on your belly and then you've got equipment all over you two. So there's three people in there, a pilot and two observers. The observers, are mostly, involved in obviously making observations, taking notes, managing the cameras. I, I've done it enough that I've been able to drive the vehicle, but there's a pilot who's the primary person and will spend somewhere between ten and maybe 12 hours on the seafloor.
It, descends at about 30 to 40m a minute. So when we're working those depths of over six kilometers, we're spending a couple hours to descend another couple of hours to come back up, and then, you know, leaving us maybe six hours or so on the seabed. And during that time, because we're untethered from the ship. We're not it's not doesn't have a tether like a remotely operated vehicle. Power is quite limited. Payload is quite limited.
But on a typical geology dive, which is something that untethered vehicles are really good for, so we can drive around and explore, we might cover a kilometer to a kilometer and a half of seabed. We might pick up something like 20 rocks using the manipulators. The pilot does all of that. It's, it's a tight, enclosed space. I don't notice it myself because I spend all my time looking out the window, being excited about what I'm seeing.
But in my, you know, many, dozens of dives, I've experienced the full range of partners in the sub. Some freak out, many of them get ill. But it's it's truly a surreal experience. And this that you you load into the sub while it's still on the ship. And from the moment they pick you up, you go inside and they seal the hatch, and then they pick you up on a on a winch, and then they kind of swing you overboard.
And so as soon as the vehicle starts swinging independently of the ship, and then when they drop you in the water and there's a big splash and there's scuba divers around that are disconnecting things and getting you ready to deploy. It's it's just an amazing experience. And I would say that you you stop feeling the movement of the ocean, maybe within the first ten meters of descent, it really and they don't launch in Rothesay State anyway.
But once once you get down a little bit below the surface, becomes very calm. The lighting is amazing. It gets less and less as you go down until, you know, roughly about 150, 160m is where we stop seeing any, any light. And if we descend without the lights on, you can see all sorts of, organisms that phosphorescence. It's, it's it's a incredible thing. And I still remember the, you know, the first time I saw an active hydrothermal vent is just absolutely incredible.
You know, the world's all dark. Then you turn on the lights, you see this incredible, otherworldly ecosystem popping out in front of you. It's it's spectacular. I wish everyone could have that experience. And and in a way, everyone can, because there are now several, organizations that do live streaming of their remotely operated vehicle operations on the seabed. And, that brings this science to, you know, many people around the globe.
When I participate in those expeditions, we have people that sort of follow the different organizations that do these things. You see the same people on in the chat asking questions. And it's it's it's an honor to be able to bring that science to the general public.
But I will say at the same time, being in the Alvin submersible, where there's just three of us in there, there's no communication with the surface, but we're in a vehicle this much more nimble, much, more able to, make delicate sampling operations. We're seeing things in true 3D representation by looking out the portholes. Whereas with a remotely operated vehicle, the pilots are using a series of cameras to infer the 3D relationships.
It's it's a it's a much better experience for those in the vehicles. It's essentially like being a geologist on land and walking to outcrops and as we're driving along and if I see something interesting, I can see the pilot, hey, can we go back and look at that thing I just saw? I want to understand it a little bit more. They can do that when you're, on with a tethered vehicle, a remotely operated vehicle. This is very complex interplay between the pilots that are controlling the vehicle.
One person is managing the cable, which connects it back to the ship, the ship which is also moving. And you have to worry about never touching the seabed with that cable. And if you're in steep terrain, which is what a lot of volcanic terrain is, it's you can't necessarily just stop and go back and look at something. You have to sort of watch it go by and keep moving. Yeah. So if there's, an underwater volcano, can you see them without turning the lights on? The only two times.
And I participated in both those expeditions where we've seen active volcanism in the deep ocean. One was it Northwest Rota volcano, which is in the Marianas arc in, the year 2005. That was a very, very small, subdued eruption. But it was the first we had seen. And, you know, it's it's only 570m deep, which it's officially considered the deep sea. But, for me, it's not really all that deep. The most impressive display we saw was at West model Kino.
This is in Tonga, and that summit is about, 1200 meters deep. And in 2009, we went out there and, observed for about a week an active volcanic eruption. And it's absolutely spectacular view. And your listeners can search on the, on the web for West Mata eruption, and you will find plenty of video footage. That was a research expedition co-sponsored by National Science Foundation in the US and the National Oceanographic and Atmospheric Administration's Ocean Explorer program, also in the US.
And I've been back to that volcano ten times since, including with funding from both those agencies as well as Schmidt Ocean Institute, which runs a global philanthropic oceanographic organization. We've never seen it erupting again. And in fact, that's sort of how I convinced Schmidt Ocean Institute to to take us back there. We we, you know, nicknamed our expedition submarine fire. And when we arrived on the volcano, we found out the heat erupted about two months before we were there.
We just missed it. But this place erupted quite frequently, interrupts much more frequently than, Axial volcano, which is the famous volcano on the wonderful ridge of the north western coast of the United States. I've also studied it's 1998, 2011 and 2015 eruptions, the last two in person. After the fact, of course. The 2015 eruption was interesting because they had just installed infrastructure on the volcano that forms the basis of a submarine volcano observatory.
It was still being tested and and preliminary, and we detected the event, but debated about whether or not it was eruption or not, because the signals we were seeing weren't the same kind of signals that we've picked up from land base stations at other volcanoes in that area. And so it wasn't until several months later that we decided to go out there. And in fact, there had been an eruption that had been an extensive eruption.
People are now predicting that that volcano might be ready to erupt, this year, those predictions are very first order. They're not particularly precise. They're based on how much the volcano inflates as magma comes in from below. But as we know from other volcanoes that are well instrumented, such as Kilauea, which is currently erupting on the big Island in Hawaii right now, that magma does come in and cause the volcano to inflate, and we have various ways we can measure that.
But, certain amounts of inflation will sometimes lead to an eruption and sometimes not. Mauna Loa volcano, the world's largest active volcano, which had last erupted in 1984. And I moved to Hawaii in 1992. And I was waiting for years and years and years. We would see very signals of inflation and seismic and unrest, and then the volcano wouldn't erupt. And then, of course, a couple of years ago, it finally did erupt.
And it was it was an amazing eruption sequence that was, well observed by people at the U.S. Geological Survey's volcano observatory. But just the fact that multiple times in that sort of 30 year, 40 year period, that inflation was observed and it didn't erupt tells us that sometimes magma comes into the shallow part of a volcano and it doesn't breach the surface. It fills in the cracks and voids. It will sometimes migrate along with zones. And so it's this is a complicated process.
And in fact, more salicylic or more viscous high silicon content magma such as we find it, island arcs and continental arcs and other continental volcanic settings often slowly accumulate in volcanic edifices and don't necessarily erupt.
They can accumulate for hundreds of thousands of years between eruptions and lead to much larger and more explosive eruptions, so that something about how viscous the magma is, which is a combination of the temperature and the composition and the crystal content. And of course, viscosity is a measure of how runny or sticky a magma is. That really affects how it erupts, how often erupts, how it behaves. One it arrives. What kind of deposits it makes. One it erupts.
And so the the nature of magmas that are relatively hot and relatively thin, or what we call low viscosity, are the kind that we tend to find at volcanoes and erupt quite frequently, and to make the types of deposits that we'll be talking about today, one of the fascinating things about both Pele's hairs and Pele's tears is we find them at submarine volcanoes as well.
The deepest place they've been identified yet is, at about 4500m depth at some, submarine, Hawaiian volcanic sites known as North Arch. They're the north of the island of Oahu. Famously a former, Ted of the, Hawaii Volcano Observatory in the 90s who then later became, researcher at the Monterey Bay Aquarium Research Institute. Dave Clark is the person who who spent much of his latter career looking for these materials. The rest of us thought, no, come on, that's not actually happening.
But in how we would find them is mostly, rooting around in the sediment that's around these volcanoes and finding these, sieving the sediments and separating out these materials. And he's published multiple papers on them. There's some debate about the mechanisms through which they form. Again, because of the impacts of pressure as we go down deeper in the ocean. But, yeah, they tend to be found that the hairs tend to be much shorter.
It's hard to find a Pele's hair, and this could just be because of how we do the sampling. But it's hard to find one more than 5 or 6cm when we're in an underwater setting. And of course, in, on land settings, we can find these things to 20, 30cm long, and they'll oftentimes occur in clumps where many hairs are together. Whereas when we see them, in submarine settings, they tend to be individuals. Strands. If you do find them on land, is it sort of like a small bush? Is it?
I don't know, like a field of it. So you can find them in a variety of different settings. The primary location is very close to a volcanic finch. When isn't all that active.
So oftentimes at basaltic fissure volcanoes, which is what, all the main Hawaiian volcanoes are, which means that there is oftentimes a crater or a caldera at the summit, and then rift zones, which are areas of repeated injections of magma in the subsurface in a particular direction, which then will erupt along these eruptive fissures, very, very similar to the processes that happened in Iceland. In fact, the ongoing eruption in Iceland is also a Fisher eruption and also makes Pele's hair.
And in those cases, real life times see a series of small volcanic vents along the line. Some of them that are maybe erupting a little bit less intensely are the ones that we will find the Pele's hairs at. There's some famous locations near the summit of Mount Ulloa, where some past, prehistoric eruptions have produced large deposits of both Pele's hairs and something else that we call reticulate.
And it doesn't have any, specific Hawaiian name that I'm aware of, but but reticulate is a spongy texture, sort of spun glass material that has hair like filamentous features, but it's much more three dimensional. And so within those passes, we can oftentimes find Pele's hairs and in clumps that, you know, might be the size and shape of something like a cucumber or banana.
It's rare to find it, more extensive than that, but you can find occasional deposits that are that are larger, perhaps as big as your arm. Now, of course, scientists should be always aware of working with and understanding the needs and beliefs and cultures of local communities whenever their work encroaches on their land or land that they deem as sacred.
You may remember that the construction of telescopes on Mount Kenya has led to significant conflicts between the scientific community and the Native Hawaiians. They do consider that mountain to be sacred, and it was out of those tensions that a new oversight board, the Manicare Stewardship and Oversight Authority, was established to manage the mountain top.
The board has representatives from both the Astronomical Observatory and the Native Hawaiian communities, and the aim is to foster collaboration and ensure that future developments respect cultural and environmental concerns. And I wondered whether there are similar discussions or need for such discussions with regard to the volcanoes and Pele's tears and Pele's hair. So that's that's a it's an it's an intriguing question.
I would say that the name Pele shares and Pele's tears, is a name that was, added by Westerners after they arrived. So you know that, although there's some people that think that perhaps the Spanish arrived in the islands, before Captain Cook. The first documented Western appearances were in 1790, and the, pretty quickly introduced the English language. And so, you know, obviously, Pele's hairs in tears are in, English adaptation of, of this feature or English naming.
So I would say, while Hawaiians, have, a reverence for pretty much all volcanic processes, all volcanic activity, I don't think that, the hairs and tears necessarily have any specific significance, in part because they are pretty commonly formed feature and they don't represent any sort of extraordinary behavior of a volcano. So there can be times when the volcano is behaving very violently, which would be thought of as manifesting, you know, the emotion of the God at the time.
Pele is upset at someone, for instance. There are many periods of time where the volcano can, erupt very quiescent, quietly. So, for instance, during, the first part of this century, until 2018, starting in about the mid 2000, there was a lava lake, which is a kind of boiling caldera or cauldron. I should say, of magma within the caldera. For most of the latter third of the 19th century, the volcano also had active, lava lakes. And this was one sort of tourism.
Hawaii just started, and people would go and stand there in their Sunday best and take a photo in front of the volcano and when someone's acting like that, the magma is injected from below and there's this sort of molten lake of lava that is constantly overturning and stir stirring, but it doesn't produce any any Pele's hairs. Interestingly enough, every once in a while we observed, during the active lava lake activity in the summit, in holy mackerel mantle crater, earlier this century.
Sometimes rocks would fall in from the wall and they splash and they would kind of disrupt the lake and allow some more gas rich magma that was being suppressed deeper in the lake to come up and erupt. Explosive. And then we would see here, hairs and tears and other associated, gentle pyroclastic associated with that. So that's something that we would call a secondary eruption deposit, because it's not juvenile magma on its first way up from depth to the surface.
And, and erupting at the site or wherever it happens to erupt on a volcano. It's something that was already, in effect, erupted. But then disturbed and re erupted. Another related phenomena which is again super common in Iceland.
And not as common in Hawaii, but happens sometimes is another kind of what we call secondary volcanic deposit, where if you have a lava flow is flowing across a land surface and encounters a wet or a boggy area, or encounters the coastline in the ocean, then that water can flash to steam and come up through the lava flow and create the. The formation of small pyroclastic, which are molten volcanic fragments, are injected into the air. Getting Pele's hairs.
And Pele's tears can be made in that process. And we call when when it's lava that's meeting the ocean, we call that a lateral eruption. And so this is this is a very common phenomenon there in Iceland. The most famous example other than 30, which, of course was the island that formed in the 60s off the coast is, at the volcano in the northeast, where Lake Netherton, which is a very large, broad, lake next to the volcano, has experienced lava flows that have been poured into it.
And so there's a whole series of volcanic cones which you can still find today. Pele's hairs and tears associated with those cone deposits. And these were formed because lava flows flowed maybe ten kilometers from, the volcanic caldera over this wet landscape.
Everything that comes out of volcano gets studied, whether it's, pieces of the magma, whether it's fragments of dust, whether it's volcanic gases, and pretty much everything tells us about the pantheon of processes that happen at a volcano. You can imagine these are incredibly dynamic environments where we can have a range of compositions. We can have a range of, conditions in evolution of pressure and temperature. Particles can be flying at supersonic velocities.
They can be, cooling at different rates and the magma composition can be different. And so Pele's hairs and tears are part of the range of particle types. Allow us to interrogate some of the more quiescent, shall I say volcanic phenomena that happen. It doesn't it doesn't mean that it's safe to go up to a volcano when they're producing these things, but these tend to be at the lower energetic rate of processes that can happen when, magma is erupted onto the land surface.
And so by studying them, studying, for instance, the range of compositions, the range of textures, the amount of gases in the stored and still dissolved in the magma, the rate at which crystals seem to grow as we look at, Pele's hairs and tears deposits as we move with distance from an active volcanic vent. All of these things tell us about the kinetics or the rate of phenomena that are happening within the volcano, in the rate of change of conditions in volcanic parameters.
So they're super, super important. As you know, a monitor of what's happening in a volcano we can observe with our eyes today. And therefore, when we find them in deposits in the past, for instance, think of, you know, eruptions that happened in Roman times at Vesuvius. How might some of those eruptions have taken place on a minute by minute basis, as a function of the deposits that we find, including the the tears and hair?
If you was sort of given the opportunity to be part of a mission to IO or somewhere where there were, yes, yes. Oh, no. Amazing. Amazing, really, even even at the drop of a hat, you can. Absolutely. You know, it didn't didn't take me a nanosecond when I did my first dive. I've gone to volcanoes. This is highs. Cotopaxi is 17,000ft above sea level in Chile. I, the opportunity to witness these things in person, obviously would be amazing.
I don't think we're ever going to get there in person at least. You know, in, in in the next few centuries, perhaps in millennia. But, for instance, if there were an opportunity to get to Mars and to study the volcanism there, for sure. And the reason being that the, the cause of volcanism on io is so interesting, right? It has to do with the gravitational attraction of, of Jupiter and some of the neighboring moons.
But in the type of magmas that are being produced, the types of volcanic deposits that are forming, these are to some extent we can see these things remotely, but the way that they impact the both the types of magma compositions in the volcanic materials as they're, ejected onto the land surface would be invaluable to see happening in real time.
Because even when when we saw those very first volcanic eruptions under the sea, the the range of things that we were seeing with our own eyes was well beyond what I could imagine. By having spent hundreds of hours looking at old volcanic eruption deposits. You know, you can see a lava flow and you can imagine your mind what must have been happening when it was produced, until you see it actually happening and you realize, oh, that's just curious.
And that that isn't what I thought was, you know, going to be the phenomenon. So I think it's it's it's definitely something that we need to strive for is to, to get observational tools to as many active volcanic bodies as we have in our solar system to get a better feeling. The range of processes. Do you have a look at the moon and wonder what it was when it was? Absolutely.
It's, it's it's a wonderful thing to look at with a high powered telescope, because you can still actually see quite a few features there that the, the there's still some debate about when the last significant volcanism happened on, on the moon. But but most people put, you know, a date of about three and a half to 3.9 billion years on it. And most of that volcanism was very extensive.
Even bigger than, but equivalent in scale to, for instance, the very large igneous provinces we find on Earth, which is the, Cretaceous, tertiary or now named pillaging, Cretaceous pillaging boundary deposits in India, the Deccan Traps, the Columbia Flood River basalts, the Siberian Traps, the. These are very large outpourings of of lava that we we can only infer. Very few of the volcanic vent structures are still left. So we can see these very thick lava flows.
It must have been enormous injection of material into the atmosphere that we don't really find the evidence for anymore. But the the lava flows themselves, we we make emphasis on the basis of what we see at places like, like Kilauea and, you know, other basaltic volcanoes around the world. But but we actually be able to see something like that would be amazing. Yeah. Anybody would. Listen, I probably should let you go very much.
I just, there's places that people can look up, a little bit more if they're interested. In addition to, you know, the material is found in the physics world, article that was recently written, but there's also, in information about Pele's, hairs and tears at the U.S. Geological Survey website. British Geological Survey has a little section on it.
So it's something that when if people want to Google about it, they can actually find reputable sources of information from scientific organizations on the web. I'd like to thank both Professors Thomson and Kenna for talking to me for this episode of Physics Bull Stories podcast, and if you would like to know more, and indeed read that article that kind of just mentioned on Physics Welcome, you'll find it entitled Pele's Hair Raising Physics Glossy Gifts from a Volcano Goddess.
But Samir Sagal will be back next month with something else from this wonderful world of physics. And thank you very much for listening. Hello and welcome to the Physics World Stories podcast. I'm Andrew Lester, and in this episode we're going to be exploring Pele's hair and Pele's tears. These extraordinary wave structures formed by volcanic eruptions can help us understand the dynamics of those eruptions.
Atmospheric processes and planetary geology here on Earth, and quite possibly out there in the solar system. And there are plenty of tales of derring do, including exploring the depths of the ocean, volcanoes in submarine, because we'll hear from two people who spent their careers so far studying volcanoes soon we'll hear from Tamsin Mather of the University of Oxford.
But first, I wanted to know why the name Pele in Pele's and Pele's tears came from and in case you're wondering, it's nothing to do with the footballer. Here's Kenna Rubin, who spent 30 years as a volcanologist on the island of Hawaii. Pele is volcano goddess in Hawaii and interestingly enough, she resize or is thought to reside underneath Kilauea volcano. And, you know, a little bit just to inject a tiny bit of Polynesian history here.
There were various waves of migration of Hawaiians or the people that populated the Hawaiian Islands, first from the areas that, we now know or of as French Polynesia and Marcos's in Tahiti, and they brought various Polynesian gods with them in the volcano. God that they brought was named Isla out and Isla and was, very, sort of warful God, a God who was subject to fits of temper.
And in fact, scientists at the Hawaii Volcanoes have correlated this observation and personification of Isla out with a phase of explosive volcanism. A Kilauea volcano which ended in the 1790s, and Pele was brought to Hawaii as a concept by Samoans that started to migrate to the islands maybe 3 or 400 years later. There are many, of the Davies in the Polynesian religion which are similar across the islands. Pele's one who is different.
And so when Pele came to the islands, she took on a somewhat different vibe. Pele is, also, known to be a vengeful god. She lusted after many men. And then after, enjoying relations with those men, she would oftentimes turn them into features of the landscapes. There are many volcanic features on all of the islands are named after people that Pele supposedly turned into.
These features, for one reason or another, and her arrival in the Hawaiian Islands is thought to coincide with the transition to a more, subdued, lava flow, what we call effusive volcanic style. Just a little tidbit. The 2011, excuse me, 2018 eruption at Kilauea on the, eastern south southeast rift zone that erupted in the neighborhood. If you recall, it was the Leilani Estates eruption.
Some people thought that that was a return or resurgence of either out because of the violence of the eruption, as well as the collapse of the volcanic caldera that was happening up at the summit of the volcano. That hasn't necessarily been borne out in the subsequent, activity.
But this is this is something that, very important to the people in Hawaii is, personifying processes not just in the volcanoes, but up in the atmosphere, different states of weather, the who controls the wind in the waves and the coral reefs with the deities.
And so I say that because while it's important to respect everyone's cultural perspectives and their religions, it also gives us an important way of understanding the way Hawaiians interact with their natural landscape, the renewal of the land that happens because of volcanic phenomena, and the instability of the land because of the volcano. We'll hear much more from kind of later in the podcast, including her adventures exploring underwater volcanoes.
But first, let's go to Tamsin Mae, the professor of earth sciences at the University of Oxford. For more than 20 years now, I've been studying the world's volcanoes. I guess some of the highlights are going out there and, and seeing volcanoes in the wild, so to speak.
So standing next to fire fountains on Mount Etna in Italy, down in Sicily, staring into massive, roiling lava lake, going to Hawaii and, and studying the, emissions coming out to the hello mama crater, hiking down into the jungle in Guatemala to sample rocks. That's just a few amazing Pele's hair and Pele's tears. Oh, they're really extraordinary rocks. Actually, they really, really do look like, hair.
When you have a basaltic lava lake or lava event or lava flow with bubbles bursting on its surface, when the the bubbles break, they can kind of, extrude and stretch, the glassy rock. So the magma, freezes and forms glassy threads, which then blow up or waft up with the volcano's hot gases, and get deposited on the ground or caught in fences or on, on ridges and vegetation around the volcano.
And it looks just like from a distance, looks pretty much like kind of animal hair, like dark sheep's hair or something like that, caught on a fence. But then when you pick it up, it's brittle, and glassy and actually can be quite sharp and you can get it stuck in your fingers and things. So it's really extraordinary stuff. That is a away you have, they sit, they, they fly out and you have the, the droplets from the top of bubbles bursting.
So if you ever looked at, a slo mo of a water bubble bursting, sometimes you get a drop at the top. So sometimes they're formed like that, and then sometimes they're just the sort of more gloopy end of the, of the extrusion. So you actually get a Pele's hair, which terminates in a police tear, and they are exactly as they sound. The that shaped glassy blobs, that then, pretty small, and then get wafted up with the volcanic gases. So they must be cooling very quickly then. Yes.
Particularly the glass shards, because they're so fine and thin. They have a very high aspect ratio. They call really, really quickly. And that's why you get glass rather than having many crystals forming in them. Okay. But if you were sort of walking along, not that you'd want to be while this was going on right now, I assume. But if you were walking along in this sort of did get in your hair, that would be problematic.
I the worst place it could be in your eyes because, as I say, these, these glassy shards that if you rubbed your eyes, you might break them and you get sharp. But since you're into your eyeball, which would be, I'd imagine, deeply unpleasant. Fortunately, it hasn't happened to me as yet. Okay, but imagine the tears are quite if one of those struck you as it had been blasted out of a volcano, that would hurt quite a bit. They're pretty small, and actually, not that they're not that heavy.
They're quite light. So, that's not too much raw. Okay. So enough. But what you can do with them is pick them up, take them back to the lab and study them. Yes. So the great thing, I mean, utterly beautiful and amazing. Wonderful. And fascinating. But the great thing, as well as because they've quenched so they've cool really, really quickly. And you've got this glossiness, it means you've, you've got a, kind of, you've got a total composition, if you like.
It hasn't separated off into the different crystal phases. So you can just crush it up, or probe it with, with a different beam technology. And you can get the composition of the glass that was there in the lava, like, you know, pretty much as you walk past. So, so that's a real advantage to them. You know, you kind of know the, you know, that they, they don't persist for long, long periods of time in the environments. You know, that they've just been there probably a few weeks at maximum.
And if you clear a surface and then collect some more of them, you know, that that's really fresh stuff. So you know, that of representative of the magma composition there and then in the lava lake or on the lava flow. But what does that tell us, knowing that kind of composition? So, a bunch of different things, really. So one of the things we might be interested in is the fluid properties of the magma. So, how viscosity is, how sticky it is.
So one of the things we want to know about for that would be the, the silica content. So silica and oxygen, because silica shouldn't form polymers in the magma. So the more silica an oxygen you have, the stickier a magma tends to be. So the lower that is, the runny and magmas are if it's getting stickier, then that might change the way that the dynamics of the lava flows or the eruption might go.
You might also want to look at things like dissolved water content, because that also affects how sticky a business of my flour is. And also the dissolved water content, determines how volatile, how volatile rich the magma is and how explosive it might or might not be. So if you, for example, looking, at a long lived lava lake like in Hawaii, you might be interested in how these different parameters are changing with time.
And that might also give you clues about what's going on deep inside the volcano. How often would you be finding them? How often do these conditions arise? It's hard to say how often this I mean, this is quite specific set of conditions. You need a dynamic, lava or magma, interface with bubbles bursting or that you need the, the, the the magma to be low enough viscosity that you can get this extrusions happening.
So it's not you know, it's certainly in my career, I've been in this situation sort of 3 or 4 times where that being said, if Pele's had deposits around, so it's not it's not super rare, but it's also not something you necessarily expect every single time you go to a volcano. So all of the volcanoes that you've looked at are on land. Most of the world's volcanoes are underwater, most of them at the mid-ocean ridges, but those are pretty deep under the waves. They're quite hard to study.
I certainly studied some, some shallow submarine volcanoes. I believe that people have found Pele's hair in submarine volcanoes, but I've never studied that myself. When you set off to go to a volcano, you're looking for specific things. Or you just like, let's go and find out what's going on there.
Well, I mean, I go to volcanoes for a number of different reasons, but probably the times that I've been and collected Pele's hair as well is when I've been studying the gas emissions from the volcanoes. And I want to understand how much of the different components are coming out. And sometimes that might be the major gas species, like water, carbon dioxide, sulfur dioxide.
And then we might be wanting to see think about what we can tell in terms of what those gases tell us about the subterranean plumbing of the volcano and its status in terms of hazard. But other times I'm thinking about the environmental impact of volcanoes. So I'm interested in all sorts of different elements coming out, all sorts of, different metal species coming out.
One of the interesting things there is if we, if we measure the metal, species, metal, chemical, chemical species, if I did the plumes, the different salts and and things like that. You're interested to find out how that compares to their concentrations in the magma? Because what you'd like to understand is how volatile the different metals are. So how easily they are transferred from the magma to the gas phase.
Because if we can understand more about what that means, we can make predictions about how it might behave under volcanoes based on just a lava sample or, or a glass sample. So we're not we're not always there yet, but that's the sort of aspiration we'd like to understand more about that degassing process of, of different elements in the periodic table. So that's somewhere where I might be very excited to find some place that's going to tell me about the magma in the, in the, in the magma event.
Right at the moment, pretty much that I'm measuring the gases sitting on the edge of the volcano. Different, different chemicals are cycled through our planet in natural cycles and different ways. Volcanoes are part of that in terms of providing a conduit for different chemicals between the solid Earth and the environment on the atmosphere. So we'd like to understand how it's operating today so that we can think about how it might have varied over geological time.
Is that something that would inform our understanding of climate change? More broadly, yes. I mean, the carbon dioxide and sulfur dioxide are a major, major sort of, climate, elements. So we are interested in how volcanoes are forced climate back in geological time, because sometimes that gives us clues in terms of the sort of massive carbon release experiment that we're currently undertaking as a species, the consequences thereof. Volcanoes have released, a lot of carbon.
So big events and volcanic past these things called large igneous provinces. So if you go to somewhere like the Deccan in India, actually we've got some here in the UK, if you go to northern sky, you can see these big stacks of basaltic lava flows. And these are the remnants of, of large igneous provinces. And these are these enormous outpourings of largely basaltic magma onto the surface of the planet. And they last about a million years.
But they put about 1,000,000km³ of magma onto the surface of the Earth. So just one cubic km of magma would cover the whole of Greater London to about 60cm. So this is we're putting millions of these out. They cover big areas in places like Siberia. The Columbia River in not in North America, for example. So during these logic, these provinces that sort of doubled the rate of volcanism on our planet and doubled the rate of carbon dioxide being put out by the world's volcanoes on our planet.
So we're interested to see what the environmental consequences of that are, because right at the moment, we're doing even more than that. You know, we're we're we're doing 60 times the amount of carbon dioxide that comes out of the world's volcanoes. So, you know, we're beating the logic. These provinces, we've been at this a much shorter length of time. We've only been at it for a couple of centuries.
But, you know, so far we're we're best in class at carbon dioxide emissions compared to volcanoes. And and so we are we're interested to study, understand how much carbon came out, which is where sitting in volcanic plumes today is of interest. And and also just the consequences. And, we see some pretty strong consequences. We see, we see mass extinction events associated with these large igneous provinces. We see episodes of global ocean anoxia.
So when all the oxygen in the oceans got depleted and you get these black shale layers and the geological record of, of oxygen depleted, of oxygen, diagnostic of oxygen depletion in the oceans, for example. So, so that's why it's a sort of interesting comparison to understand the environmental impacts of volcanoes. It's not the only way to understand what we're doing, what what our consequences are as a geological force, by any means. But it's one of the ways that we might go after that.
What is it that attracted you to to this area of study? Well, so I did a chemistry degree and, and then had a couple of years at science and decided I wanted to go back to doing science. I would do I didn't just want to be in the lab. I liked lab work, but I also wanted to be outdoors and sampling the world and kind of understanding large scale processes, as well as the sort of what was going on in, in a test tube or even smaller.
And so I was looking around at environmental chemistry projects, and I happened to find this one, on the, the atmospheric chemistry of volcanic plumes. And I'd done some specialist modules in atmospheric chemistry, so I thought I might be able to give that one a go. And, the rest is history. As I say, I think the study of Pele's hair is part of a wider projects in volcanology. I mean, there are there are papers written specifically on Pele's hair, talky Pele's tears.
It talks about the shapes, cataloging the shapes, looking at, the singularity. This is a bubble structure within the Pele's tears. And talk about how those relate to things like the viscosity of magmas, for sure. But, but for me, I think, they are really interesting as part of our wider endeavor to really understand volcanic processes, both looking, peering in and looking down and thinking deeper into the earth, but also, looking outwards and thinking about the consequences of volcanoes.
So the other piece of the puzzle, they tell us another piece of, information, other pieces of information that we can build into bigger pictures. It seems like it would be a slightly treacherous, way to spend your time studying volcanoes, if you had any particularly hairy adventure, Harry. No pun intended. Well, it was it was intended. Fortunately, not too much. I mean, I've certainly been scared of the volcano. I think it's right to be a bit scared.
Your your, you know, your high alert. You should be. You're on a an unpredictable, natural phenomenon. I do try to be very, very careful. I, I am not, I do not take risks for the sake of taking risks. I, very, very adamant that no measurement is worth taking undue risk for. We always talk very carefully to the local scientists who are monitoring the volcano. Now, not all volcanoes worldwide, are perfectly monitored. Or or even well monitored.
So sometimes you do have to take a bit of a risk. But. Yeah. Just to get me to give you an example. So, Santi, due to volcano in Guatemala, which is where we were hiking down into the jungle to do some play, it was a bit frightening because the volcano has, you know, small, smallish, but still sizable explosion. About every 45 minutes. So you'll go down the jungle, there's this volcanic, cone above you. Boom. Every 45 minutes. Pyroclastic flows come down the side of it.
Now, we'd looked at the map, so we talked to the local scientists. We need the pyroclastic flows basically went down into a big, big valley and went off a different direction. But when you're underneath a volcano, you can't see that. You just see the power tastic flame coming towards you. And, you know, just hoping it's not going to appear up the other side of the, of the other sides of the valley. And it didn't, we sampled our rocks and and hiked out again. But, but yeah, it is.
They are you must we it is really important to respect the the volcanoes and to be as careful as you possibly can. How long is the risk assessment? Yeah, well, it could run to several, many pages. Normally had some very detailed maps and lots of notes of contact numbers. I wanted to know more about these underwater volcanoes and the possibilities and realities of exploring them. Kind of.
Reuben is a professor at an associate dean for research at the Graduate School for oceanography at the University of Rhode Island. So in my current position, I am responsible for the research portfolio of a school of oceanography that means shepherding programs and projects, managing our ship and shore based facilities, managing our research personnel. I also have about a third of my job. The still dedicated to research. My research is in volcanology and oceanography.
I moved to the University of Rhode Island two years ago, from a 30 year career as a professor at the University of Hawaii in, the Department of Earth Sciences, where I spent a great deal of time studying both Hawaiian volcanism and my particular specialty, which is submarine volcanism, including the deepest known active volcanic spots under the sea on the planet, on the volcano side. Who doesn't love volcanoes? They're spectacular. They're awesome.
They are, fascinating to study, I guess, understanding how they function. For me, I'm especially interested in how they erupt, how often they erupt, how eruptions impact the environment, how they impact ecosystems. And that's part of my interest in both. So the aerial meaning above water and submarine, which is underwater eruptions. My love of the ocean started from a very, very young age. I've always enjoyed the sea, studying it, being in it, being around it, being able to see it.
And so, I have a merger of those two things. It's been a wonderful, an exceptional career. I've had more than 30 expeditions at sea. I've had more than, 60 dives in, human occupied submersible, another several hundred in remotely operated vehicles and one of the things that few of us who study submarine, volcanoes, it's a relatively small community, but few of the other folks who do this kind of work also have experience, working on volcanoes, on land.
So for me, seeing what happens on land and understanding which which features are similar, which features are not, and how the, increasing depth as we go down further from the surface, under the ocean affects volcanic processes to some extent. It doesn't affect them at all. To other extents, it affects them very greatly.
And this is something that is interesting not only for studying the range of volcanism on the planet, but also understanding how volcanism might happen on other planetary bodies, such as Venus, whose atmospheric pressure is very similar to what we find in relatively deep submarine settings on Earth. Okay, going in submersibles and looking at underwater volcanoes, I mean, that sounds like something James Cameron would want to do. He and he has done it.
And so most of my work, especially my deep diving work below about two kilometers, has happened with, Woods Hole Oceanographic Institution using their vehicle. Alvin. In fact, we just published an article last week in EOS, the American Geophysical Union's weekly news magazine, about the recent deep diving upgrade to the vehicle. We can now take it to 6500m depth, which is, you know, more than 20,000ft for those who still use the imperial system.
And on one of the dives on that program, I discovered what we now know is the deepest on Earth, submarine volcanic deposit, about 60 100m depth in the Mid Cayman Rise.
And what's fascinating is, is that even though the very high hydrostatic pressure, the pressure from the weight of all that water pressing down on such a deep, seabed location, one would think would have that would affect the evolution of volatiles or gases that become unresolved from magmas and drive a lot of eruption processes, including Pele's hairs. But to some extent, those phenomena happen even at those very great depths.
And this is one of the things is so interest ING about getting to make these observations in those locations. Can you just sort of describe that experience to me, of being in one of those submersibles and arriving at the volcano here? It's it's not for everyone. So, in fact, it is a two meters here in about, a third of that sphere in the horizontal direction is filled up with equipment.
And then you sort of, you know, you sit on your side or lie on your belly and then you've got equipment all over you two. So there's three people in there, a pilot and two observers. The observers, are mostly, involved in obviously making observations, taking notes, managing the cameras. I, I've done it enough that I've been able to drive the vehicle, but there's a pilot who's the primary person and will spend somewhere between ten and maybe 12 hours on the seafloor.
It, descends at about 30 to 40m a minute. So when we're working those depths of over six kilometers, we're spending a couple hours to descend another couple of hours to come back up, and then, you know, leaving us maybe six hours or so on the seabed. And during that time, because we're untethered from the ship. We're not it's not doesn't have a tether like a remotely operated vehicle. Power is quite limited. Payload is quite limited.
But on a typical geology dive, which is something that untethered vehicles are really good for, so we can drive around and explore, we might cover a kilometer to a kilometer and a half of seabed. We might pick up something like 20 rocks using the manipulators. The pilot does all of that. It's, it's a tight, enclosed space. I don't notice it myself because I spend all my time looking out the window, being excited about what I'm seeing.
But in my, you know, many, dozens of dives, I've experienced the full range of partners in the sub. Some freak out, many of them get ill. But it's it's truly a surreal experience. And this that you you load into the sub while it's still on the ship. And from the moment they pick you up, you go inside and they seal the hatch, and then they pick you up on a on a winch, and then they kind of swing you overboard.
And so as soon as the vehicle starts swinging independently of the ship, and then when they drop you in the water and there's a big splash and there's scuba divers around that are disconnecting things and getting you ready to deploy. It's it's just an amazing experience. And I would say that you you stop feeling the movement of the ocean, maybe within the first ten meters of descent, it really and they don't launch in Rothesay State anyway.
But once once you get down a little bit below the surface, becomes very calm. The lighting is amazing. It gets less and less as you go down until, you know, roughly about 150, 160m is where we stop seeing any, any light. And if we descend without the lights on, you can see all sorts of, organisms that phosphorescence. It's, it's it's a incredible thing. And I still remember the, you know, the first time I saw an active hydrothermal vent is just absolutely incredible.
You know, the world's all dark. Then you turn on the lights, you see this incredible, otherworldly ecosystem popping out in front of you. It's it's spectacular. I wish everyone could have that experience. And and in a way, everyone can, because there are now several, organizations that do live streaming of their remotely operated vehicle operations on the seabed. And, that brings this science to, you know, many people around the globe.
When I participate in those expeditions, we have people that sort of follow the different organizations that do these things. You see the same people on in the chat asking questions. And it's it's it's an honor to be able to bring that science to the general public.
But I will say at the same time, being in the Alvin submersible, where there's just three of us in there, there's no communication with the surface, but we're in a vehicle this much more nimble, much, more able to, make delicate sampling operations. We're seeing things in true 3D representation by looking out the portholes. Whereas with a remotely operated vehicle, the pilots are using a series of cameras to infer the 3D relationships.
It's it's a it's a much better experience for those in the vehicles. It's essentially like being a geologist on land and walking to outcrops and as we're driving along and if I see something interesting, I can see the pilot, hey, can we go back and look at that thing I just saw? I want to understand it a little bit more. They can do that when you're, on with a tethered vehicle, a remotely operated vehicle. This is very complex interplay between the pilots that are controlling the vehicle.
One person is managing the cable, which connects it back to the ship, the ship which is also moving. And you have to worry about never touching the seabed with that cable. And if you're in steep terrain, which is what a lot of volcanic terrain is, it's you can't necessarily just stop and go back and look at something. You have to sort of watch it go by and keep moving. Yeah. So if there's, an underwater volcano, can you see them without turning the lights on? The only two times.
And I participated in both those expeditions where we've seen active volcanism in the deep ocean. One was it Northwest Rota volcano, which is in the Marianas arc in, the year 2005. That was a very, very small, subdued eruption. But it was the first we had seen. And, you know, it's it's only 570m deep, which it's officially considered the deep sea. But, for me, it's not really all that deep. The most impressive display we saw was at West model Kino.
This is in Tonga, and that summit is about, 1200 meters deep. And in 2009, we went out there and, observed for about a week an active volcanic eruption. And it's absolutely spectacular view. And your listeners can search on the, on the web for West Mata eruption, and you will find plenty of video footage. That was a research expedition co-sponsored by National Science Foundation in the US and the National Oceanographic and Atmospheric Administration's Ocean Explorer program, also in the US.
And I've been back to that volcano ten times since, including with funding from both those agencies as well as Schmidt Ocean Institute, which runs a global philanthropic oceanographic organization. We've never seen it erupting again. And in fact, that's sort of how I convinced Schmidt Ocean Institute to to take us back there. We we, you know, nicknamed our expedition submarine fire. And when we arrived on the volcano, we found out the heat erupted about two months before we were there.
We just missed it. But this place erupted quite frequently, interrupts much more frequently than, Axial volcano, which is the famous volcano on the wonderful ridge of the north western coast of the United States. I've also studied it's 1998, 2011 and 2015 eruptions, the last two in person. After the fact, of course. The 2015 eruption was interesting because they had just installed infrastructure on the volcano that forms the basis of a submarine volcano observatory.
It was still being tested and and preliminary, and we detected the event, but debated about whether or not it was eruption or not, because the signals we were seeing weren't the same kind of signals that we've picked up from land base stations at other volcanoes in that area. And so it wasn't until several months later that we decided to go out there. And in fact, there had been an eruption that had been an extensive eruption.
People are now predicting that that volcano might be ready to erupt, this year, those predictions are very first order. They're not particularly precise. They're based on how much the volcano inflates as magma comes in from below. But as we know from other volcanoes that are well instrumented, such as Kilauea, which is currently erupting on the big Island in Hawaii right now, that magma does come in and cause the volcano to inflate, and we have various ways we can measure that.
But, certain amounts of inflation will sometimes lead to an eruption and sometimes not. Mauna Loa volcano, the world's largest active volcano, which had last erupted in 1984. And I moved to Hawaii in 1992. And I was waiting for years and years and years. We would see very signals of inflation and seismic and unrest, and then the volcano wouldn't erupt. And then, of course, a couple of years ago, it finally did erupt.
And it was it was an amazing eruption sequence that was, well observed by people at the U.S. Geological Survey's volcano observatory. But just the fact that multiple times in that sort of 30 year, 40 year period, that inflation was observed and it didn't erupt tells us that sometimes magma comes into the shallow part of a volcano and it doesn't breach the surface. It fills in the cracks and voids. It will sometimes migrate along with zones. And so it's this is a complicated process.
And in fact, more salicylic or more viscous high silicon content magma such as we find it, island arcs and continental arcs and other continental volcanic settings often slowly accumulate in volcanic edifices and don't necessarily erupt.
They can accumulate for hundreds of thousands of years between eruptions and lead to much larger and more explosive eruptions, so that something about how viscous the magma is, which is a combination of the temperature and the composition and the crystal content. And of course, viscosity is a measure of how runny or sticky a magma is. That really affects how it erupts, how often erupts, how it behaves. One it arrives. What kind of deposits it makes. One it erupts.
And so the the nature of magmas that are relatively hot and relatively thin, or what we call low viscosity, are the kind that we tend to find at volcanoes and erupt quite frequently, and to make the types of deposits that we'll be talking about today, one of the fascinating things about both Pele's hairs and Pele's tears is we find them at submarine volcanoes as well.
The deepest place they've been identified yet is, at about 4500m depth at some, submarine, Hawaiian volcanic sites known as North Arch. They're the north of the island of Oahu. Famously a former, Ted of the, Hawaii Volcano Observatory in the 90s who then later became, researcher at the Monterey Bay Aquarium Research Institute. Dave Clark is the person who who spent much of his latter career looking for these materials. The rest of us thought, no, come on, that's not actually happening.
But in how we would find them is mostly, rooting around in the sediment that's around these volcanoes and finding these, sieving the sediments and separating out these materials. And he's published multiple papers on them. There's some debate about the mechanisms through which they form. Again, because of the impacts of pressure as we go down deeper in the ocean. But, yeah, they tend to be found that the hairs tend to be much shorter.
It's hard to find a Pele's hair, and this could just be because of how we do the sampling. But it's hard to find one more than 5 or 6cm when we're in an underwater setting. And of course, in, on land settings, we can find these things to 20, 30cm long, and they'll oftentimes occur in clumps where many hairs are together. Whereas when we see them, in submarine settings, they tend to be individuals. Strands. If you do find them on land, is it sort of like a small bush? Is it?
I don't know, like a field of it. So you can find them in a variety of different settings. The primary location is very close to a volcanic finch. When isn't all that active.
So oftentimes at basaltic fissure volcanoes, which is what, all the main Hawaiian volcanoes are, which means that there is oftentimes a crater or a caldera at the summit, and then rift zones, which are areas of repeated injections of magma in the subsurface in a particular direction, which then will erupt along these eruptive fissures, very, very similar to the processes that happened in Iceland. In fact, the ongoing eruption in Iceland is also a Fisher eruption and also makes Pele's hair.
And in those cases, real life times see a series of small volcanic vents along the line. Some of them that are maybe erupting a little bit less intensely are the ones that we will find the Pele's hairs at. There's some famous locations near the summit of Mount Ulloa, where some past, prehistoric eruptions have produced large deposits of both Pele's hairs and something else that we call reticulate.
And it doesn't have any, specific Hawaiian name that I'm aware of, but but reticulate is a spongy texture, sort of spun glass material that has hair like filamentous features, but it's much more three dimensional. And so within those passes, we can oftentimes find Pele's hairs and in clumps that, you know, might be the size and shape of something like a cucumber or banana.
It's rare to find it, more extensive than that, but you can find occasional deposits that are that are larger, perhaps as big as your arm. Now, of course, scientists should be always aware of working with and understanding the needs and beliefs and cultures of local communities whenever their work encroaches on their land or land that they deem as sacred.
You may remember that the construction of telescopes on Mount Kenya has led to significant conflicts between the scientific community and the Native Hawaiians. They do consider that mountain to be sacred, and it was out of those tensions that a new oversight board, the Manicare Stewardship and Oversight Authority, was established to manage the mountain top.
The board has representatives from both the Astronomical Observatory and the Native Hawaiian communities, and the aim is to foster collaboration and ensure that future developments respect cultural and environmental concerns. And I wondered whether there are similar discussions or need for such discussions with regard to the volcanoes and Pele's tears and Pele's hair. So that's that's a it's an it's an intriguing question.
I would say that the name Pele shares and Pele's tears, is a name that was, added by Westerners after they arrived. So you know that, although there's some people that think that perhaps the Spanish arrived in the islands, before Captain Cook. The first documented Western appearances were in 1790, and the, pretty quickly introduced the English language. And so, you know, obviously, Pele's hairs in tears are in, English adaptation of, of this feature or English naming.
So I would say, while Hawaiians, have, a reverence for pretty much all volcanic processes, all volcanic activity, I don't think that, the hairs and tears necessarily have any specific significance, in part because they are pretty commonly formed feature and they don't represent any sort of extraordinary behavior of a volcano. So there can be times when the volcano is behaving very violently, which would be thought of as manifesting, you know, the emotion of the God at the time.
Pele is upset at someone, for instance. There are many periods of time where the volcano can, erupt very quiescent, quietly. So, for instance, during, the first part of this century, until 2018, starting in about the mid 2000, there was a lava lake, which is a kind of boiling caldera or cauldron. I should say, of magma within the caldera. For most of the latter third of the 19th century, the volcano also had active, lava lakes. And this was one sort of tourism.
Hawaii just started, and people would go and stand there in their Sunday best and take a photo in front of the volcano and when someone's acting like that, the magma is injected from below and there's this sort of molten lake of lava that is constantly overturning and stir stirring, but it doesn't produce any any Pele's hairs. Interestingly enough, every once in a while we observed, during the active lava lake activity in the summit, in holy mackerel mantle crater, earlier this century.
Sometimes rocks would fall in from the wall and they splash and they would kind of disrupt the lake and allow some more gas rich magma that was being suppressed deeper in the lake to come up and erupt. Explosive. And then we would see here, hairs and tears and other associated, gentle pyroclastic associated with that. So that's something that we would call a secondary eruption deposit, because it's not juvenile magma on its first way up from depth to the surface.
And, and erupting at the site or wherever it happens to erupt on a volcano. It's something that was already, in effect, erupted. But then disturbed and re erupted. Another related phenomena which is again super common in Iceland.
And not as common in Hawaii, but happens sometimes is another kind of what we call secondary volcanic deposit, where if you have a lava flow is flowing across a land surface and encounters a wet or a boggy area, or encounters the coastline in the ocean, then that water can flash to steam and come up through the lava flow and create the. The formation of small pyroclastic, which are molten volcanic fragments, are injected into the air. Getting Pele's hairs.
And Pele's tears can be made in that process. And we call when when it's lava that's meeting the ocean, we call that a lateral eruption. And so this is this is a very common phenomenon there in Iceland. The most famous example other than 30, which, of course was the island that formed in the 60s off the coast is, at the volcano in the northeast, where Lake Netherton, which is a very large, broad, lake next to the volcano, has experienced lava flows that have been poured into it.
And so there's a whole series of volcanic cones which you can still find today. Pele's hairs and tears associated with those cone deposits. And these were formed because lava flows flowed maybe ten kilometers from, the volcanic caldera over this wet landscape.
Everything that comes out of volcano gets studied, whether it's, pieces of the magma, whether it's fragments of dust, whether it's volcanic gases, and pretty much everything tells us about the pantheon of processes that happen at a volcano. You can imagine these are incredibly dynamic environments where we can have a range of compositions. We can have a range of, conditions in evolution of pressure and temperature. Particles can be flying at supersonic velocities.
They can be, cooling at different rates and the magma composition can be different. And so Pele's hairs and tears are part of the range of particle types. Allow us to interrogate some of the more quiescent, shall I say volcanic phenomena that happen. It doesn't it doesn't mean that it's safe to go up to a volcano when they're producing these things, but these tend to be at the lower energetic rate of processes that can happen when, magma is erupted onto the land surface.
And so by studying them, studying, for instance, the range of compositions, the range of textures, the amount of gases in the stored and still dissolved in the magma, the rate at which crystals seem to grow as we look at, Pele's hairs and tears deposits as we move with distance from an active volcanic vent. All of these things tell us about the kinetics or the rate of phenomena that are happening within the volcano, in the rate of change of conditions in volcanic parameters.
So they're super, super important. As you know, a monitor of what's happening in a volcano we can observe with our eyes today. And therefore, when we find them in deposits in the past, for instance, think of, you know, eruptions that happened in Roman times at Vesuvius. How might some of those eruptions have taken place on a minute by minute basis, as a function of the deposits that we find, including the the tears and hair?
If you was sort of given the opportunity to be part of a mission to IO or somewhere where there were, yes, yes. Oh, no. Amazing. Amazing, really, even even at the drop of a hat, you can. Absolutely. You know, it didn't didn't take me a nanosecond when I did my first dive. I've gone to volcanoes. This is highs. Cotopaxi is 17,000ft above sea level in Chile. I, the opportunity to witness these things in person, obviously would be amazing.
I don't think we're ever going to get there in person at least. You know, in, in in the next few centuries, perhaps in millennia. But, for instance, if there were an opportunity to get to Mars and to study the volcanism there, for sure. And the reason being that the, the cause of volcanism on io is so interesting, right? It has to do with the gravitational attraction of, of Jupiter and some of the neighboring moons.
But in the type of magmas that are being produced, the types of volcanic deposits that are forming, these are to some extent we can see these things remotely, but the way that they impact the both the types of magma compositions in the volcanic materials as they're, ejected onto the land surface would be invaluable to see happening in real time.
Because even when when we saw those very first volcanic eruptions under the sea, the the range of things that we were seeing with our own eyes was well beyond what I could imagine. By having spent hundreds of hours looking at old volcanic eruption deposits. You know, you can see a lava flow and you can imagine your mind what must have been happening when it was produced, until you see it actually happening and you realize, oh, that's just curious.
And that that isn't what I thought was, you know, going to be the phenomenon. So I think it's it's it's definitely something that we need to strive for is to, to get observational tools to as many active volcanic bodies as we have in our solar system to get a better feeling. The range of processes. Do you have a look at the moon and wonder what it was when it was? Absolutely.
It's, it's it's a wonderful thing to look at with a high powered telescope, because you can still actually see quite a few features there that the, the there's still some debate about when the last significant volcanism happened on, on the moon. But but most people put, you know, a date of about three and a half to 3.9 billion years on it. And most of that volcanism was very extensive.
Even bigger than, but equivalent in scale to, for instance, the very large igneous provinces we find on Earth, which is the, Cretaceous, tertiary or now named pillaging, Cretaceous pillaging boundary deposits in India, the Deccan Traps, the Columbia Flood River basalts, the Siberian Traps, the. These are very large outpourings of of lava that we we can only infer. Very few of the volcanic vent structures are still left. So we can see these very thick lava flows.
It must have been enormous injection of material into the atmosphere that we don't really find the evidence for anymore. But the the lava flows themselves, we we make emphasis on the basis of what we see at places like, like Kilauea and, you know, other basaltic volcanoes around the world. But but we actually be able to see something like that would be amazing. Yeah. Anybody would. Listen, I probably should let you go very much.
I just, there's places that people can look up, a little bit more if they're interested. In addition to, you know, the material is found in the physics world, article that was recently written, but there's also, in information about Pele's, hairs and tears at the U.S. Geological Survey website. British Geological Survey has a little section on it.
So it's something that when if people want to Google about it, they can actually find reputable sources of information from scientific organizations on the web. I'd like to thank both Professors Thomson and Kenna for talking to me for this episode of Physics Bull Stories podcast, and if you would like to know more, and indeed read that article that kind of just mentioned on Physics Welcome, you'll find it entitled Pele's Hair Raising Physics Glossy Gifts from a Volcano Goddess.
But Samir Sagal will be back next month with something else from this wonderful world of physics. And thank you very much for listening.