Bird Pinkerton (3:03)

So this is unexplainable. I'm Bird 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. 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?

Mike Poland (3:55)

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 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 they 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, 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.

Bird Pinkerton (5:12)

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

Mike Poland (5:19)

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. Right. 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 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 the. These episodes of volcanism.

Bird Pinkerton (6:05)

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.

Mike Poland (6:44)

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. It makes sense, right?

Bird Pinkerton (6:59)

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

Mike Poland (7:04)

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

Bird Pinkerton (7:12)

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

Mike Poland (7:21)

In this way you can basically do something that's akin to like taking an MRI of the Earth. You can do that with magnetics and gravity. The most common way to do it with seismic waves. So as seismic waves pass through the Earth, if they encounter something hot and maybe partially molten, they're going to slow down.

Bird Pinkerton (7:43)

Okay.

Mike Poland (7:44)

And if they hit something really solid and cold, they're going to speed up. And we can measure the travel times of seismic waves as they pass through the subsurface and put a map together of how fast things are moving through the subsurface.

Bird Pinkerton (8:04)

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

Mike Poland (8:18)

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, maybe it's a week old cake, 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.

Bird Pinkerton (8:46)

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.

Mike Poland (8:58)

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

Bird Pinkerton (9:14)

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 the death by a super volcanic Yellowstone explosion off of our list of imminent apocalypse scenarios. But before you breathe too easily, there are still lots of other ways for Yellowstone to kill you.

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Today Explained Host (10:45)

Okay, so you may have heard New York City gets a new mayor this week. 34 year old Democratic socialist Zoran Mamdani. Mamdani's election was one of the biggest wins for the left in 2025. But since then he's been quietly going about a new task, trying to make sure his sweeping campaign promises can actually happen.

Mike Poland (11:05)

An agenda that will freeze the rents for more than 2 million rent stabilized tenants, make buses fast and free, and deliver universal childcare across our city.

Bird Pinkerton (11:16)

I'm a little skeptical about how he's.

Mike Poland (11:18)

Going to get everything done. I think that's what a lot of people are promised. So many things like free buses, you know, housing and all that.

Today Explained Host (11:26)

Promises, promises in this kind of politics succeed. Or is this Bom Donny's high point the days before he gets into office? On this episode of Today Explained from box, we sit down with New York City's mayor elect and ask him directly, is he for real? That's this week on Today Explained.

Mike Poland (11:52)

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

Bird Pinkerton (11:59)

In our conversation about Yellowstone, Mike told me, sure, a volcanic supereruption 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, strong earthquakes, the.

Mike Poland (12:23)

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 and it caused an entire mountainside to collapse.

Bird Pinkerton (12:38)

Oh my God.

Mike Poland (12:38)

And that mountainside rushed through a campground at about midnight and it killed a lot of people. 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.

Bird Pinkerton (13:08)

Oh my God.

Mike Poland (13:10)

That's pretty consequential.

Bird Pinkerton (13:11)

So that's hazard number one.

Mike Poland (13:13)

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

Bird Pinkerton (13:19)

Wait, what is a steam explosion?

Mike Poland (13:22)

So you are dealing with 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, and that creates a condition where you can have water flashing to steam. And when that happens, you have rapid expansion and kaboom.

Bird Pinkerton (13:56)

Taking you to Wyoming. Now, Yellowstone national park rangers closed the Biscuit Basin area today after a hydrothermal explosion happened this morning.

Mike Poland (14:06)

That's what happened on July 23, 2024 at Biscuit Basin, only about 2 1/2 miles or so from Old Faithful. There was a really dramatic steam explosion sending a black plume of steam and mud up to the sky. 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. Scientists at Yellowstone tell us that this was a random event without warning. That kind of thing happens almost all the time in Yellowstone. It's, 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 carrier where you've got a lot of boiling water just beneath the surface.

Bird Pinkerton (15:02)

Is that a predict, like you can't.

Mike Poland (15:04)

Say ooh that's tough.

Bird Pinkerton (15:06)

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

Mike Poland (15:13)

Yeah, right. I mean, if your pressure cooker has a crack in it or something, you know, like, is it going to work? Is it not going to 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. So it's possible that there are precursors. We don't know that.

Bird Pinkerton (15:35)

Are you trying to figure that out?

Mike Poland (15:37)

Yeah. Oh, absolutely.

Bird Pinkerton (15:39)

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 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.

Mike Poland (16:44)

So maybe we should be looking at the electrical activity, the conductivity, the resistivity of the subsurface, basically passing kind of electricity through the 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 have any examples where we've been measuring these things at a place that's blown up.

Bird Pinkerton (17:15)

Right. So sure, sure.

Mike Poland (17:16)

You know, it's. It's a. It's almost like a whack a mole game.

Today Explained Host (17:19)

Right.

Mike Poland (17:20)

We know Biscuit Basin Blue, Black Diamond Pool and Biscuit Basin Blue. So we'll go run out there and we'll put a bunch of stuff in area. Black Diamond Pool, and two years from now some other pool will blow up.

Bird Pinkerton (17:29)

Right.

Mike Poland (17:30)

And Then we'll run over there and do something. Why don't you have equipment at every pool? Couple years after that? Limited equipment.

Bird Pinkerton (17:36)

Yeah. Okay.

Mike Poland (17:37)

If I wanted to, if I wanted to pay $7 trillion zillion and you could put equipment in every pool. Well, but there's also, there's also a, 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? Yes, that's actually my dream paved paradise.

Bird Pinkerton (18:05)

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?

Mike Poland (18:23)

I think it causes us to focus on the wrong things. Emphasizing something that is the literally one in a million chance. I find it disappointing because it's like Yellowstone is stunning, right? Iconic landscapes, charismatic megafauna, right? Bison, elk, bears, wolves. Oh my. Boiling water is shooting out of the ground at a lot of places with some regularity. That's amazing. It sells itself, but why turn it into this boogeyman? So I find that lazy and kind of, if I'm really going to reach, kind of disrespectful to the landscape and to the place. And I do think it distracts from things that are really consequential.

Bird Pinkerton (19:29)

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

Mike Poland (19:45)

Well, this is, this is the amazing thing, right? It varies so much in this small corner of Wyoming.

Smartsheet Advertiser (19:51)

Right.

Mike Poland (19:51)

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 and right next to it boiling water is shooting up out of the ground 100ft in the air.

Bird Pinkerton (20:40)

I gotta go to Yellowstone.

Mike Poland (20:42)

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

Bird Pinkerton (20:54)

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 Bird Pinkerton. It was edited by Joanna Solotarov 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 for the fact that hedgehogs can swim. Thanks to Thomas Lu for his help and edits on this episode. And I'm always, always, always grateful to Brian Resnick for co founding the show with 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@ unexplainable vox.com 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 you signed up because of Unexplainable, just thank you. Like thank you very much. If you cannot join our membership though, that is okay. If you wanted to leave us a nice review on your podcast platform, we would appreciate that a lot. Or if you just wanted to tell someone in your life that they might want to listen to the show, that would make a real difference. Genuinely though, we just makes a big difference that you listen. So thank you. Thanks for listening all the way through the credits and Unexplainable is part of the Vox Media Podcast network. We'll be back soon with another episode about everything we don't yet know. Sam.