Who's afraid of big, bad Yellowstone?

Yellowstone can be a deadly place... but not for the reasons you might think. Guest: Mike Poland, scientist in charge at the Yellowstone Volcano Observatory For show transcripts, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠⁠[email protected]⁠⁠⁠⁠. We read every email Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

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• 1:39Speaker 00

  When I was a kid, I remember hearing about Yellowstone.

• 1:44Speaker 00

  I remember hearing that it was a national park, that it had a big volcanic system with lots of geysers. And I remember hearing this really scary story about it. A story that Mike Poland, the scientist in charge of the Yellowstone Volcano Observatory, basically knows by heart. He hears versions of it all the time.

• 2:05Speaker 02

  You would have heard that Yellowstone has had incomprehensibly big eruptions.

• 2:12Speaker 00

  Yes.

• 2:13Speaker 02

  And this is true. You may also have heard that Yellowstone is brewing and stirring away, and one day is going to have another one of these eruptions, and we don't know when. It could be tomorrow. And if it does that, then it could mean the end of the human race. I may be pushing things a little far. I hear that a lot. And these things just aren't, they just aren't true.

• 2:44Speaker 00

  I'll be honest, this was news to me. I called up Mike to ask him, what's the deal with Yellowstone? Right? Like, will there be an eruption any day? Why don't we know? Et cetera. And instead, he told me that there is a lot that we don't know about predicting volcanoes. Like, we wound up doing a whole episode on just that subject. But when it comes to Yellowstone specifically and eruptions in the near future, scientists like Mike have a lot of confidence.

• 3:16Speaker 02

  We can look at what's happening beneath the surface and understand whether or not we're brewing or getting ready for an eruption. And we know that's not the case at Yellowstone. So Yellowstone is not a threat in terms of volcanic activity in the immediate future.

• 3:33Speaker 00

  So, this is Unexplainable. I'm Bert Pinkerton. And today on the show, why Mike is so confident that, at least in this one respect, the Yellowstone system is pretty explainable. But also, Mike will tell us some mysteries about Yellowstone that he would like to solve.

• 4:14Speaker 00

  So if it's not true that Yellowstone is going to erupt imminently, or it could erupt at any time, where did that idea come from in the first place?

• 4:25Speaker 02

  So the discovery of Yellowstone as a really, really massive volcanic system was really kind of late 50s, early 60s, when geologists started looking at the region and understanding the rocks that were there. It had been known to be a volcanic region for a long time. Then geologists started to identify the rocks, started to become more familiar with the rocks in the area and realized that some of the rocks they were seeing weren't lava flows, it was compressed ash. And all of this started to sort of come together as a story, that Yellowstone has had some really, really big eruptions. The ash was so thick that it welded itself together, it became incredibly dense. And it would have swept across the landscape

• 5:07Speaker 02

  for, who knows, 100 miles, something like that, from its source, just sort of sweeping the area clean. These were really, really big eruptions that also would have had an impact on climate, because it would have put a tremendous amount of ash into the atmosphere that would have reflected sunlight and caused some cooling. And so that's a fantastic story. Will that happen again one day? Maybe. It's hard to tell. And if it does happen in the future, none of us that are on Earth now are going to be around to be able to know whether or not it happened, right? So in some ways, I find it kind of a funny question.

• 5:42Speaker 00

  Mike told me there are a couple of things that make him so confident here. One is just looking at Yellowstone's geological record.

• 5:50Speaker 02

  This is not something that's going off all the time. You walk into the Yellowstone landscape, and it doesn't look like Hawaii, where there's nothing growing, because these lava flows are so recent. Clearly, the stuff that had come out was relatively old. That doesn't mean it's inactive, it doesn't mean it won't happen again at some point in the future. It will have episodes of lava flows that...

• 6:10Speaker 02

  May occur, but the last one of those was 70,000 years ago. It can have really massive explosions, maybe once every million years, maybe slightly less than that. But it is clear that this system was not just constantly going off all the time, that there were long pauses between eruptions. So we appear to be in one of those periods of quiet, not in the middle of these episodes of volcanism.

• 6:35Speaker 00

  And the geological record also holds clues to help us understand when we might need to start worrying. So for example, if you look at old lava from Yellowstone, it's apparently full of tiny crystals. Those crystals grew back when the lava was magma, so inside the earth, and they grew in layers. You can think of them almost like tree ring layers. And just like tree ring layers can tell you stuff about bygone weather or bygone water levels, the layers on these volcanic crystals record moments of intense heat down in the magma chamber, for example.

• 7:13Speaker 02

  So we can use the crystals as a clue of what the magma chamber might have looked like through time. And what we generally see is that there is some sort of like thermal event, like a heating event, prior to eruptions. Makes sense, right?

• 7:29Speaker 00

  Right. Like you would, it would make sense that you'd be like, oh, right before there was an eruption, things got hot.

• 7:34Speaker 02

  Yeah, things got kicked up, things got jump-started.

• 7:37Speaker 00

  And apparently volcanologists can monitor a system like Yellowstone to see if that's happening currently, to see if heat is coming in to jump-start an eruption in this way.

• 7:52Speaker 02

  You can basically do something that's subkinda like taking an MRI of the earth. You can do that with magnetics and gravity. The most common way to do it was with seismic waves.

• 8:03Speaker 02

  So as seismic waves pass through the Earth,

• 8:07Speaker 02

  if they encounter something hot and maybe partially molten, they're going to slow down.

• 8:14Speaker 00

  Okay.

• 8:14Speaker 02

  And if they hit something really solid and cold, they're going to speed up.

• 8:21Speaker 02

  And we can measure the travel times of seismic waves as they pass through the subsurface and can put a map together of how fast things are moving through the subsurface.

• 8:34Speaker 00

  When they peer down under Yellowstone, they can see that it's definitely hot down there, but not so hot that they anticipate a supervolcanic eruption. Essentially, it's not melted enough.

• 8:48Speaker 02

  Imagine a lava cake that is like, I don't know, 10 years old. And, you know, a lot of that chocolate just is not flowing anymore. There might be some pieces that are still, you know, maybe not 10 years old. Maybe 10 is a bit much, but you know.

• 9:05Speaker 00

  Maybe it's a week old, cake words.

• 9:07Speaker 02

  Maybe it's a week old, right. And so when you slice into it, you know, nothing moves. There's no flowage there because it's, you know, 80% solid.

• 9:16Speaker 00

  Now, if you took Yellowstone and injected a lot of heat somehow, if magma came up from below to heat up the whole system, it would be like putting your lava cake back in the oven.

• 9:27Speaker 02

  That would melt that gooey center and you'd be back to having your lava cake. That's maybe a good analogy for Yellowstone. And we haven't seen that rejuvenation event. We're dealing with a system that is, you know, a couple of week old lava cake.

• 9:44Speaker 00

  And this couple of weeks old lava cake is just probably not going to end the world in a fiery nightmare of ash and lava. And so this is why Mike is so prepared to allay people's concerns on this one. Based on all the information that he and his fellow volcanologists have at their disposal, he really does think we can check death by a supervolcanic Yellowstone explosion off of our list of imminent apocalypse scenarios.

• 10:13Speaker 00

  But before you breathe too easily, there are still lots of other ways for Yellowstone to kill you.

• 10:35Speaker 00

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• 14:04Speaker 03

  You come barging in here asking me to contribute money to a volcano relief fund for crack a toast. It was supposed to erupt!

• 14:12Speaker 00

  In our conversation about Yellowstone, Mike told me, sure. A volcanic super eruption maybe does not need to keep us up at night. But that doesn't mean that Yellowstone is this totally benign place. There are other hazards that could happen in our lifetime that we might want to think about instead. Hazards like, for example...

• 14:33Speaker 02

  Strong earthquakes.

• 14:34Speaker 00

  Hmm.

• 14:35Speaker 02

  The largest earthquake ever recorded in the Intermountain West was just a few miles west of Yellowstone National Park. It was a magnitude 7.3 in 1959.

• 14:47Speaker 02

  And it caused an entire mountainside to collapse.

• 14:50Speaker 00

  Oh my god.

• 14:51Speaker 02

  And that mountainside rushed through a campground at about midnight. And it killed a lot of people, well, over two dozen people died. It dammed a river. And it created a new lake. And the Army Corps of Engineers and some local folks had to get in there very, very fast and build a temporary spillway. Because if they hadn't done that, the debris dam could have failed catastrophically. And then you would have had a flood going down this river and then taking up some towns downstream.

• 15:21Speaker 00

  Oh my god.

• 15:22Speaker 02

  That's pretty consequential.

• 15:24Speaker 00

  So that's hazard number one.

• 15:26Speaker 02

  The other one, a steam explosion, like what we saw in July of 2024.

• 15:31Speaker 00

  Wait, what is a steam explosion?

• 15:34Speaker 02

  So you are dealing with a, at Yellowstone, a very poorly engineered pressure cooker or Instapot, or depends on your generation, I suppose, for which analogy you want to use. There is a lot of boiling water just beneath the surface. It is flowing through conduits that are constantly having minerals precipitate out into them. And so they're getting clogged and pressure builds. And that creates a condition where you can have water flashing to steam. And when that happens, you have rapid expansion and kaboom.

• 16:09Speaker 04

  Taking you to Wyoming now. Yellowstone National Park Rangers closed the Biscuit Basin area today after a hydrothermal explosion happened this morning.

• 16:18Speaker 02

  That's what happened on July 23rd, 2024, at Biscuit Basin, only about two and a half miles or so from Old Faithful. There was a really dramatic steam explosion.

• 16:28Speaker 05

  Sending a black plume of steam and mud up to the sky.

• 16:32Speaker 02

  No one was injured fortunately, but there were a lot of people that were in the area and had to run away from rock and mud, boiling water that was flying all over the place.

• 16:40Speaker 05

  Scientists at Yellowstone tell us that this was a random event without warning.

• 16:44Speaker 02

  That kind of thing happens almost all the time in Yellowstone. It's annually, there are explosions, maybe not that dramatic. And certainly, that was one of the best viewed ones because it was in the summertime at a well-visited geyser basin, you know, during the day on a beautiful blue sky day. But that kind of thing has been a hazard we've been trying to emphasize for a long time. And it's a hazard any place, any volcanic carry where you've got a lot of boiling water just beneath the surface.

• 17:14Speaker 00

  Is that a predict, like, you can't say-

• 17:17Speaker 02

  Ooh, that's tough.

• 17:18Speaker 00

  Right. The same way that it's hard to predict when your pressure cooker is gonna go off.

• 17:25Speaker 02

  Yeah, right. I mean, if your pressure cooker has a crack in it or something, you know, like, is it gonna work? Is it not gonna work? I don't know. Maybe it'll blow up, maybe it won't. It's possible that there is some indication, and we just haven't been able to see it yet because we're either not measuring in the right place, or we're not looking at the right parameters. And so it's possible that there are precursors. We don't know that.

• 17:47Speaker 00

  Are you trying to figure that out?

• 17:49Speaker 02

  Yeah, oh, absolutely.

• 17:51Speaker 00

  The process for trying to figure out what might trigger a steam explosion involves a bunch of equipment set up to detect and measure things like low-frequency rumblings, or how the ground deforms, so how it swells or shrinks as hot rock changes beneath it. They're taking seismic readings as well. All this stuff, where the hope is that they could look through this data and say, oh, when there is a lot of rumbling, or say, a lot of deformation that looks like this, or looks like that, those tend to be signs

• 18:30Speaker 00

  that steam is about to explode. So far, they don't have the steaming gun, but Mike says that might be because their equipment hasn't been close enough to the site of any given explosion. Or, he says, it's also possible that they just haven't looked at the right data yet. Like, maybe as hot water pools just below the surface, preparing for a steam explosion, there could be an electrical charge that builds up somehow.

• 18:56Speaker 02

  So maybe we should be looking at the electrical activity, the conductivity, the resistivity of the subsurface, basically passing kind of electricity through this subsurface and seeing how well it moves. Or maybe we should be looking at magnetic properties of the materials, which will change depending on how hot it is, or how much water is moving around. Or maybe there will be changes in the temperature of the spring. Now, the challenge here is that we don't have many examples, we don't have any examples, where we've been measuring these things at a place that's blown up. Right, so

• 19:28Speaker 00

  Sure, sure.

• 19:29Speaker 02

  You know, it's almost like a whack-a-mole game, right? We know Biscuit Basin blew up, Black Diamond Pool and Biscuit Basin blew up. So we'll go run out there and we'll put a bunch of stuff in area of Black Diamond Pool. And two years from now, some other pool will blow up. Right? And then we'll run over there and do some

• 19:44Speaker 00

  Why don't you have equipment at every pool? Limited equipment.

• 19:49Speaker 00

  Yeah, okay, if I wanted to, if I wanted to pay seven trillion zillion dollars, you could put equipment at every pool.

• 19:56Speaker 02

  Well, but there's also, there's also, there's not just a financial cost to that. There is a cultural cost? I mean, do you want to go to Yellowstone and see wires and solar panels and batteries and all that stuff all over the place?

• 20:12Speaker 00

  Yes. That's actually my dream.

• 20:16Speaker 02

  Paved paradise?

• 20:17Speaker 00

  Have a parking lot, yeah. At the end of our conversation, I asked Mike why this story about an imminent Yellowstone super eruption bothers him so much. Like, what is the harm he sees in having a story like this out in the world?

• 20:36Speaker 02

  I think it causes us to focus on the wrong things.

• 20:41Speaker 02

  Emphasizing something that is the literally one in a million chance.

• 20:53Speaker 02

  I find it disappointing because it's like Yellowstone is stunning, right? Iconic landscapes, charismatic megafauna, right? Bison, elk, bears, wolves, oh my.

• 21:09Speaker 02

  Boiling water is shooting out of the ground at a lot of places with some regularity. That's amazing.

• 21:17Speaker 02

  It sells itself. But why turn it into this boogeyman?

• 21:24Speaker 02

  So I think, I find that lazy.

• 21:28Speaker 02

  And kind of, if I'm really going to reach, kind of disrespectful to the landscape and to the place.

• 21:35Speaker 02

  And I do think it distracts from things that are really consequential.

• 21:41Speaker 00

  So I asked Mike to tell me what he finds consequential about Yellowstone. What it is like to be there.

• 21:57Speaker 02

  Well, this is, this is the amazing thing, right? It varies so much in this small corner of Wyoming. You will smell pine forest and not be able to see much in any direction because you're in the middle of a really dense forest. And then you'll walk out into a meadow and there'll be a herd of bison in the meadow. Or across a really cold mountain river, there's a pack of wolves running by, something like that. And then you pass around the corner and you're hit by the smell of rotten eggs and a weird plume. And as you approach it, there's a rainbow colored spring that's steaming.

• 22:40Speaker 02

  And right next to it, boiling water is shooting up out of the ground 100 feet in the air.

• 22:52Speaker 00

  I gotta go to Yellowstone.

• 22:55Speaker 02

  It is a spectacular landscape with amazing number of stories to tell.

• 23:07Speaker 00

  If you want to hear more about volcanoes and you want to hear more from Mike Poland, please listen to our episode about the quest to build a magma observatory. It is called "The View From Inside a Volcano," and we will link to it in the transcript. This episode was produced by me, Byrd Pinkerton. It was edited by Joanna Solotaroff and Julia Longoria. Erica Huang did the mixing and the sound design. Noam Hassenfeld wrote the music. Melissa Hirsch checked our facts. Jorge Just, Meredith Hodnot, Sally Helm, and Amy Padula are the facts that hedgehogs can swim. Thanks to Thomas Lu for his help in edits on this episode. And I'm always, always, always grateful to Brian Rusnick for co-founding the show with

• 23:51Speaker 00

  me and Noam. If you have a long-held belief that you would like us to dig deeper into, or if you have ever had a wild and beautiful time at Yellowstone, please tell us about it. We are at [email protected], and we are always open to your ideas. If you'd like to support this show and the journalism that Vox does, we would love it if you would become a Vox member. It's very easy to do. Just go to vox.com/members, and you will get access to all of Vox's journalism as well. For those of you who have emailed us to let us know that you signed up because of Unexplainable, just thank you.

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