Your Questions! Road Collapse in the United Kingdom (GeoShort)

Jesse Reimink (00:02):

Welcome to planet geo the podcast where we talk about our amazing planet, how it works and why it matters to you, Chris,

Chris Bolhuis (00:17):

Hold on, hold on. Let me adjust my microphone. Yeah,

Jesse Reimink (00:19):

Please just keep

Chris Bolhuis (00:20):

No, you'd like it when I do that,

Jesse Reimink (00:23):

It's so much better. I like it. Click around, make a whole bunch of noise that I have to edit out.

Chris Bolhuis (00:27):

Oh, okay. You want me to here? Watch me go mute. Oh, on mute. There we go. Oh,

Jesse Reimink (00:32):

It's kind of better when you're muted. Oh man.

Chris Bolhuis (00:35):

It's going on, Jesse?

Jesse Reimink (00:37):

Not much, Chris, how you doing?

Chris Bolhuis (00:38):

Awesome. It suns out

Jesse Reimink (00:40):

Getting towards spring. It's beautiful. Hey, these are kind of fun episodes. We, we got a really good listener question recently. So a quick shout out to Valeria in the United Kingdom, who sent us a really interesting question about roads in Southern England, sort of buckling and breaking. And there's this one particular road near the village of Lyneham and Wilshire. And, uh, it will put a link to this news article in the show notes, but it was kind of cool and well, I mean,

Chris Bolhuis (01:05):

Crazy,

Jesse Reimink (01:06):

Crazy.

Chris Bolhuis (01:08):

It looks like it got rocked by a 9.2 earthquake. I mean, the it's absolutely destroyed the roads and unbelievable.

Jesse Reimink (01:16):

Yeah. I should not say cool. The road is completely messed up and you know, the article said there's gonna be, you know, hundreds of thousands, if not the millions of pounds worth of damage done here. But the question was, how does this happen? And I had no idea looking at this image, right, Chris?

Chris Bolhuis (01:33):

Yeah. I, same thing. I immediately started looking into it first. I read the article and start digging around and there isn't really a consensus yet on this, you know, the, they do have a, what did they call it? Like a geophysical company that's looking into this

Jesse Reimink (01:48):

Or, yeah, looking into sort of why this happened. And I think Chris, you and I both stumbled independently across an actually an AU blog written by Dr. Dave Petley from the university of Sheffield in the UK and Dr. Petley was not conclusive. Uh, definitely highlighted that there's more research needed in, in more surveys of this particular region, but suggested that maybe it was due to some reactivation of old, solifluction soil movements. Right. Which is an interesting phenomenon. And one that I think requires a definition and kind of makes for a nice little GeoShort.

Chris Bolhuis (02:22):

Yeah. I think too, it was associated with recent storms, right. Like heavy, heavy precipitation. So it makes sense. Um, yeah, let's talk about what solifluction is, cuz this is kind of a, it leads to really interesting patterned ground and yeah.

Jesse Reimink (02:40):

Yeah. So solifluction it's S O L I F L U C to T I O N so solifluction, solifluction right. So it's kind of a hard word to, to hear and know how to spell it, but um, yeah. Sorry, Chris, go ahead.

Chris Bolhuis (02:53):

This is something that you can get in, like you, I think you come across this in the Northwest territories, don't you? Solifluction, you see this probably a lot, right?

Jesse Reimink (03:03):

Yeah, absolutely.

Chris Bolhuis (03:04):

I've seen it up in, um, Tundra areas like at high up in the Rockies, um, you get some solifluction, this kind of patterned ground and you have to have something first in order for solifluction, like in the proper sun, I don't think this is what happened in the UK, but where you have what's called permafrost this permanently frozen ground beneath the surface, you know, that's gonna be up in really like the Northern territories or really, really high up in the mountains, this kind of permanently frozen ground.

Jesse Reimink (03:36):

Yeah. High latitude or high elevations in the other thing you need, you need. So you need a permafrost layer that does not melt and the soil can't move. And then you need a layer of saturated, typically water saturated soil on top of that permafrost. And then that water saturated soil at the top level can flow. And up in the Northwest territory is ready to work. You get maybe six to eight feet of soil that is above permafrost. So this is sort of the soil that melts during the summer and then freezes during the winter. But it's melted for some time of the year. And because there's permafrost below, that's an impermeable layer, the water can't make its way into the permafrost. So instead it saturates that soil and this creates this really cool pattern where the, the soil just sort of flows like molasses downhill. I don't know. That's the way I sort of think of it.

Chris Bolhuis (04:23):

No, that's a, that's a good description of it. Yeah. It's you think? I always solifluction I always, uh, say this like think of it as solar flowtion, you know,

Jesse Reimink (04:32):

That's, that's a good one. Soil flow. Yeah. Soil flowing, right. It's soil flowing downhill.

Chris Bolhuis (04:37):

And like you can see the flow. It happened a long time ago. It looks like the ground was just kind of oozing and this kind of really thick viscus material. Um, and like you hit it right on. It has to do with that permafrost because that permafrost allows the upper part of the surface to get saturated. Cuz it can't seep at permafrost. And yeah, it's a pretty cool thing to see when it's in the mountains and away from roads and things like that. But I think in the case of the UK here, right, they had these heavy precipitation and the ground just got saturated. Right. That's what happened is that's at least that's what they think.

Jesse Reimink (05:20):

It's an interesting point. And I think we have to highlight that we don't exactly know in this instance, if this is exactly what's happening, it's one sort of idea out there, but in Southern England where this occurred, there is no permafrost. So it's not actually solifluction doing it. It would be reactivation of old. Solifluction like layers basically. So this was really kind of an interesting point is that there's no permafrost there. So it's not solifluction. Like we think of it, but it's saturated soil. That's kind of moving because solifluction used to be there in the little ice age, back, you know, several hundred thousands of years ago, there was permafrost in Southern England and there was solifluction going on and you can map out these boundaries and that stuff can be reactivated by heavy rainfall. So it's a really interesting thing that you need to, I'd never really thought about this in detail that you really need to map out the soil horizons and the ancient soil movements in an area to figure out how susceptible it is to the sort of mass wasting what we call these processes that are moving soil.

Jesse Reimink (06:19):

That's

Chris Bolhuis (06:19):

Right. I wanna ask you though, what do you mean by reactivation of an old, solifluction thing? Why is that important? Well,

Jesse Reimink (06:27):

I think it, I guess it would be important. I'm not a soil expert, so I, but I I'm imagining that it would be important that if you have this really complicated soil structure

Chris Bolhuis (06:35):

Just got irritated with me for asking question. Didn't you, you just, you got a little short with me right there. You snapped at me. Oh, did I? I'm not a soil expert.

Jesse Reimink (06:42):

I am. I am not a soil expert. I just, no, I

Chris Bolhuis (06:45):

Wanted answer the question.

Jesse Reimink (06:45):

I wanted to say it cuz I clarify cuz you know, this is not speaking from an area of expertise, but you generate with solifluction. You can generate these really strange soil boundaries that are not stable. They can become unstable. If you add a lot of water into it, just like landslides in the Western us, Chris, I suppose. Right. If you add a lot of water to a really kind of slippery steeply dipping rock layer that can break off and fall into a big reservoir or something like that and create a landslide. That's right. It's the same sort of thing on a smaller scale.

Chris Bolhuis (07:17):

You think about it in term like a, from a mass wasting standpoint, water really does three things. If you add a lot of water to the Reiff to this like outer skin of the earth, it makes the stuff really heavy. It can make clay slippery and it can also, if it saturates it, it can make everything runny.

Jesse Reimink (07:37):

Right? That's a great point.

Chris Bolhuis (07:39):

It's kind of like, you know, if you take, um, if you're walking along a beach area where you have sand take moist sand and you can make a ball out of it, right. But if you add more water to it now it just turns into this oozes between your fingers as you squeeze it and try to make it just won't make a ball. It just totally loses its internal cohesion. And so that's probably, they at least that's what their thinking happened with this in this case.

Jesse Reimink (08:05):

The other thing that's interesting about this, Chris, I think is that it shows how powerful small soil movements can be. I mean, I always think of it. You know, soil creep is another mass wasting phenomenon, which we don't need to go into. But when I'm walking, uh, you know, I lived in DC for a while. You came and visited me in DC and we were walking along streets, right with old stone boundaries on the streets. So you got the hill, the house is built up on the hill and there's a stone, uh, wall that is between the yard and the sidewalk. Right. And that old stone wall is like totally tilted into the sidewalk, right? Like it, it is leaning massively

Chris Bolhuis (08:41):

And that is all the time, you know, seriously people. What happens is like when people build retaining walls, which is essentially what you're describing here, whether they build it for a bike path or terracing their yard, or doesn't matter, you build a retaining wall, you're holding back that sediment. Right? In most of the cases you had to remove a bunch of sediment to build that wall and you have to give the water a place to go, right? Because water, if it flows through the soil and it encounters that wall, it's just gonna pile up behind the wall and that's, what's causing the rock to lean into where you don't want it to go.

Jesse Reimink (09:20):

Exactly. Especially these like freeze th all cycles. I mean, it just kind of shows the power of a whole bunch of little tiny sand grains or little tiny dirt particles. If they all move in the same direction slowly, that's a really powerful force and really, really hard to stop. Like we have a hard time engineering around this sort of soil creep process. It's, it's really kind of, um, I think it's kind of cool. It can be very damaging, uh, but, but quite cool.

Chris Bolhuis (09:44):

Do you remember ever walking along the dunes that we have all over, you know, the lake Michigan shorelines and, and

Jesse Reimink (09:50):

Oh yeah, totally.

Chris Bolhuis (09:52):

and you can see great examples of soil creep those dunes because they're steep slope. Right. And so the sand, when it freezes gets lifted perpendicular to the slope and then it thaws and the sand gets let down straight down, then it, you know, keeps on doing this zigzag motion. Right. Well it affects the trees. And so right on the slope, the trees are, they're curved, they're curved down slope, but then the tree and it's quest for light straightens itself back out. So whenever you see that really steeply, curved trunk of a tree down a slope, that's a sure sign of soil creep right

Jesse Reimink (10:31):

There. Yeah. It's an amazing process. So powerful. Yeah. So powerful. So I think, I mean, I don't know. There's no answer Valeria, that's our best answer. There's no clear answer to this particular example that you highlighted to us, but I think it's a good possibility. And so it sort of highlights how powerful soil and water and soil can be and, and how damaging it can potentially be if not properly and mitigated.

Chris Bolhuis (10:58):

And also we really appreciate the question.

Jesse Reimink (11:00):

Oh, totally fun

Chris Bolhuis (11:01):

For us to look

Jesse Reimink (11:01):

Into. Yes. And in your email, you promise several more. So we expect to see those coming our way.

Chris Bolhuis (11:07):

That's

Jesse Reimink (11:07):

Right. That's right. All right. Hey, we always appreciate listener questions. You could follow us on all the social medias. We're at planet geo cast on Instagram, Facebook, and Twitter. And if you like planet geo, we just ask that you share it with people that you think might also like to learn a bit about the earth.

Chris Bolhuis (11:24):

What

Jesse Reimink (11:24):

I mean, you're just staring at me. Come on, Chris. What's going on? Well,

Chris Bolhuis (11:29):

You just stopped talking all of a sudden. Well, I don't know. You didn't gimme any cue or anything. What do you want me to say? Yeah, really good job, Jesse. Yeah.

Jesse Reimink (11:35):

Thank you. That's what I you're awesome. I want really good. Really nice, Jesse. I don't get enough compliments around here. I don't think

Chris Bolhuis (11:43):

They're, they're earned. They're not given. That's

Jesse Reimink (11:44):

True. That's true. All right. That's a wrap. See you next week.

Chris Bolhuis (11:48):

See you.