WEBVTT - Selects: How Landslides Work 0:00:00.560 --> 0:00:03.560 Hey, everyone, do you know the song Landslide sung by 0:00:03.560 --> 0:00:06.200 Stevie Nicks. Well, this is not that. This is a 0:00:06.200 --> 0:00:09.080 podcast about real landslides and how they work. And it's 0:00:09.119 --> 0:00:11.760 my pick for the Saturday Select. It's a good episode 0:00:11.760 --> 0:00:19.880 and it was from March. Check it out. Welcome to 0:00:19.960 --> 0:00:28.880 Stuff you should know, a production of I Heart Radio. Hey, 0:00:28.960 --> 0:00:31.840 and welcome to the podcast. I'm Josh Clark and Charles W. 0:00:32.159 --> 0:00:35.559 Chuck Bryant is with me as always. Hello, sir, Hello, 0:00:35.600 --> 0:00:37.920 how are you. I'm good. We've got Jerry in the house. 0:00:38.520 --> 0:00:41.640 Oh yeah, this one, uh, you know, I probably won't 0:00:41.640 --> 0:00:47.000 be our funniest podcast. And I have to say that 0:00:47.200 --> 0:00:54.000 I suggested landslides without knowing about that landslide. No, I swear, no, 0:00:54.240 --> 0:00:56.400 I promise you. I sent this to you on Monday, 0:00:57.000 --> 0:01:00.880 and then I saw like a few hours later, wow, 0:01:01.160 --> 0:01:03.480 and it was like, oh boy, I didn't you know. 0:01:03.520 --> 0:01:05.200 I was. I was on vacation, so I didn't hear 0:01:05.240 --> 0:01:10.160 about it. Um. But yeah, so it's super relevant. Well, yeah, 0:01:10.160 --> 0:01:14.680 it is apparently unintentionally relevant like our black Boxes episode. Yeah, 0:01:14.760 --> 0:01:19.440 it's been happening weirdly. But yeah, if you have been 0:01:19.840 --> 0:01:23.440 uh not paying attention to the news at all lately. 0:01:23.600 --> 0:01:25.800 Then you may not know, but there was a massive 0:01:26.040 --> 0:01:30.480 landslide in Washington as of last count I think, um, 0:01:30.520 --> 0:01:33.520 the death tolls at like twenty four which is an 0:01:33.680 --> 0:01:38.080 astoundingly high number for a landslide, uh, at least in 0:01:38.120 --> 0:01:41.559 the United States, because something like twenty five to thirty 0:01:41.560 --> 0:01:45.679 five people die in the US a year from landslides. 0:01:45.760 --> 0:01:49.640 This one was one single, enormous landslide. And if you 0:01:49.680 --> 0:01:52.960 haven't seen the pictures to get an idea of just 0:01:53.040 --> 0:01:58.160 how large it was, you should go online immediately, um 0:01:58.240 --> 0:02:01.400 and check it out because it's it was nuts what 0:02:01.640 --> 0:02:04.120 happened there. Yeah, it's about an hour north of Seattle, 0:02:04.160 --> 0:02:05.800 and I know we have a lot of fans in Seattle, 0:02:05.840 --> 0:02:08.720 so we're obviously thinking about everyone there. But um, it 0:02:08.880 --> 0:02:11.359 is you know, there's still you know, a hundred and 0:02:11.400 --> 0:02:14.560 seventy plus people missing, and it's it's it looks like 0:02:14.639 --> 0:02:18.440 it will be easily the deadliest landslide in US history 0:02:18.480 --> 0:02:19.880 by the time this is all said and done. It 0:02:19.919 --> 0:02:23.240 seems like it. But I'm clearly hoping there's more survivors. 0:02:23.280 --> 0:02:26.160 But it's just a scary man. Oh yeah, to think 0:02:26.200 --> 0:02:29.799 about like being trapped like that. And possibly still alive. 0:02:29.840 --> 0:02:32.239 It's just like the whole thing is upsetting. Yeah, because 0:02:32.240 --> 0:02:35.160 I mean, if you were inside a structure it's now 0:02:35.200 --> 0:02:38.160 covered with mud, you might you know, there's a chance 0:02:38.240 --> 0:02:41.880 that you are you're not buried, the structure around you 0:02:41.960 --> 0:02:48.600 is buried. Um. So yeah, it's uh, it's pretty awful stuff. Yeah. Um, 0:02:48.800 --> 0:02:51.120 the to me, it's even more awful. And I read 0:02:51.160 --> 0:02:55.640 an article where a resident, unnamed resident was saying like, yeah, 0:02:55.680 --> 0:02:58.600 we're not mad at the authorities, but yeah, apparently they 0:02:58.639 --> 0:03:04.320 didn't heat a lot of UM warnings. This area, the 0:03:04.440 --> 0:03:09.240 area that was covered in the landslide was known since 0:03:09.320 --> 0:03:13.040 the sixties. In the area is Slide Hill that the 0:03:13.200 --> 0:03:18.560 area itself is called the Steelhead Landslide. So like imagine if, um, 0:03:18.680 --> 0:03:22.760 the street you live on is is not an East Lake, 0:03:23.639 --> 0:03:27.320 but in Steelhead Landslide, the landslide is in the name 0:03:27.400 --> 0:03:29.400 of the area that you live. So it wasn't like 0:03:29.440 --> 0:03:33.000 the biggest surprise. No, And there was a report by 0:03:33.040 --> 0:03:36.320 the U. S. Army Corps of Engineers that predicted a 0:03:36.840 --> 0:03:42.000 UM the potential for a large catastrophic failure right there 0:03:42.000 --> 0:03:45.040 where it happened, And that's exactly what happened. The landslide happened. 0:03:45.360 --> 0:03:51.440 It covered about a square mile and um is like 0:03:51.560 --> 0:03:54.480 fifteen feet deep. Right now, Well, you can't tell people 0:03:54.520 --> 0:03:56.880 where to live though, you know, no, you definitely can't. 0:03:57.080 --> 0:03:59.440 I'm not saying they shouldn't have warned, but like people 0:03:59.480 --> 0:04:02.840 still live in flood zones and people still build their 0:04:02.880 --> 0:04:05.480 houses on the sides of a hill in Malibu, and yeah, 0:04:05.520 --> 0:04:07.800 and I guess if you're warned and like you were 0:04:07.800 --> 0:04:10.360 willing to take that risk and you wanted to, then yeah, 0:04:10.360 --> 0:04:12.360 I don't want to disagree with that, but I I 0:04:12.400 --> 0:04:15.920 don't know if um, I don't know if everybody was 0:04:16.200 --> 0:04:19.640 as aware of the potential. But apparently there was a 0:04:19.760 --> 0:04:23.679 landslide in the area as recently as two thousands six. Yeah, 0:04:23.800 --> 0:04:26.240 so apparently this was the big one and it was 0:04:26.440 --> 0:04:28.840 coming a long time and that and set off by 0:04:28.880 --> 0:04:31.279 water in this case, right. Yeah, there was word that 0:04:31.400 --> 0:04:34.159 possibly it was an earthquake, but they think though it was. Um, 0:04:34.200 --> 0:04:37.000 there was a lot of rain that that came before then. 0:04:37.680 --> 0:04:40.240 And so well, let's let's get down to explaining what 0:04:40.320 --> 0:04:44.920 happened exactly. The landslide there is actually technically a mud slide. 0:04:45.640 --> 0:04:49.040 UM and mud slides landslides, a bunch of other ones. 0:04:49.080 --> 0:04:53.160 They're all they all fall under something called mass movements. Yeah, 0:04:53.240 --> 0:04:56.080 and that is, uh, the umbrella term, and that basically 0:04:56.120 --> 0:05:00.279 means gravity is at work moving something down a slope, 0:05:00.279 --> 0:05:03.160 some kind of sediment. Um, it can be a landslide, 0:05:03.160 --> 0:05:05.440 which can it is obviously devastating, or it can be 0:05:05.480 --> 0:05:09.520 super slow over centuries. And we'll get into all that 0:05:09.560 --> 0:05:13.040 in a minute. But um, and well we'll get into 0:05:13.080 --> 0:05:15.560 all the triggers too. But I guess we should talk 0:05:15.600 --> 0:05:21.400 about their categorized depending on how fast it's moving, um, 0:05:21.440 --> 0:05:25.960 what kind of materials are being moved. Um. In every 0:05:25.960 --> 0:05:30.479 case though, you're talking about soil moving off of bedrock, 0:05:30.839 --> 0:05:34.360 the friction being overcome by gravity. That's exactly what a 0:05:34.440 --> 0:05:37.920 landslide is. And it's like super fast erosion. Yeah, on 0:05:37.960 --> 0:05:40.960 any slope you have soil over rock and it's being 0:05:40.960 --> 0:05:43.760 held in place by friction. It's kind of scary to 0:05:43.760 --> 0:05:45.919 think about it, really is. You know it's true, but 0:05:45.960 --> 0:05:48.280 then when you read it, it's like wow. Yeah. I mean, 0:05:48.320 --> 0:05:51.320 like if you've ever like dug a hole in the ground, Yeah, 0:05:51.640 --> 0:05:56.279 it's not easy. It's not like it's not like silt 0:05:56.400 --> 0:05:59.320 or something like that it's it's like ground, it's hard ground. 0:05:59.360 --> 0:06:03.240 But you know that stuff is it's not fused to 0:06:03.480 --> 0:06:07.920 the bedrock beneath it's it's there's there's a kind of um. 0:06:07.960 --> 0:06:10.240 There's a friction that's holding it in place, and that 0:06:10.320 --> 0:06:13.880 can that can fail. And that's that's what a landslide is. 0:06:14.080 --> 0:06:17.640 Exactly like you said, gravity overcomes friction. Yeah, and it 0:06:17.680 --> 0:06:21.760 can on some very large scales, it can on small scales. Um. 0:06:21.839 --> 0:06:25.560 And then like you said, depending on the type of movement, 0:06:25.680 --> 0:06:29.200 how it moves, what's moved. You have different categories of 0:06:29.240 --> 0:06:31.880 mass movements. Landslides are just one of them, or a 0:06:31.960 --> 0:06:38.360 slide is one category. There slides, creeps, slumps, and flows. Yeah, 0:06:38.440 --> 0:06:42.520 creeps are um obviously super slow. It can be uh 0:06:42.680 --> 0:06:45.719 months years, it can be centuries of creep. And that 0:06:45.880 --> 0:06:50.600 is when the sediment uh when the friction is is 0:06:50.800 --> 0:06:53.760 not working, but it's not completely destroyed, so there's still 0:06:53.760 --> 0:06:57.479 some friction. It's just moving super slow. And that's usually 0:06:57.560 --> 0:07:00.560 as a result of a lot of freezing and bowing 0:07:01.160 --> 0:07:04.240 going on to change the composition of the soil. Yeah. 0:07:04.360 --> 0:07:09.040 When the when a freeze comes through the sediment in 0:07:09.080 --> 0:07:13.400 a soil, um is pushed upward as it freezes, and 0:07:13.400 --> 0:07:16.280 when it thaws, it falls back downward. So what you 0:07:16.360 --> 0:07:19.800 have if you look at it on a geological time scale, 0:07:20.040 --> 0:07:24.360 is basically an undulation up and down of the soil 0:07:24.680 --> 0:07:27.840 that is moving downward on a slope like millimeters at 0:07:27.880 --> 0:07:31.080 a time. Right, and then uh, the telltale signs though 0:07:31.360 --> 0:07:35.280 you can see that creep is happening, because telephone poles 0:07:35.280 --> 0:07:39.640 will be kind of a skew trees or something like that. Yeah, 0:07:39.640 --> 0:07:42.680 that means that you're standing on or looking at a 0:07:43.280 --> 0:07:47.080 slumping slope and you won't see it happening. No, but 0:07:47.120 --> 0:07:49.600 I can see a pretty awesome gift. I can't remember 0:07:49.680 --> 0:07:52.960 where was it? Time lapse? Yeah, it's a time lapse gift. 0:07:53.600 --> 0:07:55.040 And it wasn't over the course of a year. Is 0:07:55.080 --> 0:07:56.760 over the course of I think several days in San 0:07:56.800 --> 0:08:00.400 Bernardino or what. Everybody's just like whoa there goes. It 0:08:00.440 --> 0:08:04.960 makes you feel unstable, Yeah, like the earth beneath your feet. Yeah, well, 0:08:05.000 --> 0:08:09.280 I mean the the earth is a constantly evolving mass. 0:08:09.760 --> 0:08:12.040 You know, soil is being moved from here to there, 0:08:12.040 --> 0:08:14.280 and there's all sorts of different agents of change, but 0:08:14.840 --> 0:08:18.240 and it moves in different ways it can creep. Yeah. Um, 0:08:18.280 --> 0:08:20.480 I think I said a slumping slope. That's not true. 0:08:20.560 --> 0:08:23.800 That was a creeping slope. Yes. A slump is when 0:08:24.240 --> 0:08:27.160 you have a big chunk that breaks off as a 0:08:27.200 --> 0:08:31.480 single whole chunk and moves. That's a slump. Yeah, And 0:08:31.480 --> 0:08:34.600 that can be the actual thing can be called a 0:08:34.640 --> 0:08:37.120 slump too. It can have a couple of meanings there 0:08:37.120 --> 0:08:39.640 for that word, like the big piece can be called 0:08:39.679 --> 0:08:42.720 a slump, or if the movement is the slump, if 0:08:42.720 --> 0:08:47.920 they're not sliding like they used to slump uh, And 0:08:47.960 --> 0:08:52.040 that is when um basically the base can't support this 0:08:52.120 --> 0:08:55.160 big chunk on top of it. And again it's usually 0:08:55.640 --> 0:09:00.200 due to uh. Moisture and water is the general cause 0:09:00.280 --> 0:09:03.439 for slumps as well. Yeah, waters, like the primary all 0:09:03.520 --> 0:09:08.200 time leading winning is cause of mass movements because either 0:09:09.120 --> 0:09:13.319 like um in a slump. A good uh analogy or 0:09:13.360 --> 0:09:15.560 a good example is if you're at the beach and 0:09:15.600 --> 0:09:18.640 you just see like a whole um, a whole hunk 0:09:18.640 --> 0:09:21.360 of wet sand cheer off of another hunk of wet 0:09:21.360 --> 0:09:25.000 sand that you just witnessed the slump And actually water 0:09:25.240 --> 0:09:30.240 can create stability for sandy, loamy or clay soil. Yeah, 0:09:30.280 --> 0:09:32.080 like you build a sandcastle, you want the sand wet 0:09:32.200 --> 0:09:35.319 exactly up to a point when you had too much 0:09:35.320 --> 0:09:37.840 water becomes saturated, and then you have a slump or 0:09:37.840 --> 0:09:40.760 you have a slider, a flow um. And then with 0:09:40.800 --> 0:09:44.559 other types of mass movement, that water can get underneath 0:09:45.200 --> 0:09:49.120 and interrupt the friction between the soil and the bedrock. 0:09:49.920 --> 0:09:52.400 And that's when you have some sort of movement as well. 0:09:52.600 --> 0:09:55.360 So that's creep and that's slump. And then finally we 0:09:55.400 --> 0:10:00.199 have flow, which is uh just basically a soupy x 0:10:00.280 --> 0:10:04.679 of water and rock and uh soil and other materials, 0:10:04.679 --> 0:10:07.559 and it's just those are usually the deadliest because it 0:10:07.679 --> 0:10:10.719 spread further. That's like a mud flower an avalanche. They 0:10:10.760 --> 0:10:14.600 get everywhere, they'll like enter into everything. It's not just 0:10:14.760 --> 0:10:16.880 it's just like a bunch of dirt. It's it's like 0:10:16.920 --> 0:10:21.600 a river moving, a fast moving river of mud in debris. 0:10:22.000 --> 0:10:27.600 And I misspoke earlier. That's um in oh So, Washington. 0:10:28.240 --> 0:10:31.920 That's what that's what that was. That was the mud 0:10:31.960 --> 0:10:35.559 flow that started it, that came down and covered everything 0:10:36.040 --> 0:10:41.360 mud which actually hampered rescue UM operations because apparently it's 0:10:41.360 --> 0:10:44.800 just like quicksand right now, suck you right in. Yeah, 0:10:45.120 --> 0:10:48.200 so in the case of well, in the case of 0:10:48.240 --> 0:10:51.120 anything other than a creep or slump, if you're talking 0:10:51.120 --> 0:10:57.640 about a quick landslide, it happens just like in a snap. 0:10:57.760 --> 0:11:00.920 It's it's going and picking up speed. But it is 0:11:00.960 --> 0:11:06.640 the result of years and years of of like slow 0:11:06.720 --> 0:11:10.720 steady erosion Blassically, it's not something that just happens out 0:11:10.800 --> 0:11:13.520 or it can be triggered. We'll talk about like earthquakes 0:11:13.559 --> 0:11:16.920 and stuff like that, but in general, it's the weathering 0:11:16.960 --> 0:11:20.959 down of objects. And I guess the difference we should 0:11:21.000 --> 0:11:25.240 describe between weathering and erosion is erosion is transporting the 0:11:25.240 --> 0:11:28.440 weather material and weathering is is the actual wearing down 0:11:28.480 --> 0:11:31.040 of that material. So they're different. Yeah. So if you 0:11:31.040 --> 0:11:35.080 have a rock that's a nice, big solid piece, millions 0:11:35.120 --> 0:11:39.440 of years later, it's been weathered into a bunch of soil, 0:11:40.160 --> 0:11:43.680 and then as as as it's lost its composition, it 0:11:43.720 --> 0:11:46.480 can move more easily, and when it moves, it's being eroded. 0:11:46.720 --> 0:11:51.920 So erosion is the is the process of movement. The 0:11:51.960 --> 0:11:54.680 weathering is everything that leads up to that ability for 0:11:54.720 --> 0:11:57.440 it to be moved. Yeah, and weathering is important because 0:11:57.480 --> 0:12:01.360 it's you're weathered landscape is going to be much more 0:12:01.440 --> 0:12:04.800 likely the landslide. Um. That's why you'll see them in 0:12:05.559 --> 0:12:07.840 more extreme environments where you get like tons of rain 0:12:08.000 --> 0:12:11.920 or like a lot of snow maybe Uh, heat, cold water, 0:12:11.960 --> 0:12:14.760 and oxygen. Those are all things that impact weathering. The 0:12:14.840 --> 0:12:17.720 cause weathering. And there's there's two types of weathering. There's 0:12:17.760 --> 0:12:22.760 mechanical weathering and there's chemical weathering. And mechanical weathering is basically, um, 0:12:22.880 --> 0:12:26.640 the material is broken down, but it retains its same 0:12:26.720 --> 0:12:30.840 chemical composition. Right it was. It's still the rock, but 0:12:30.880 --> 0:12:34.640 it was broken down into smaller pieces of itself, um, 0:12:34.840 --> 0:12:38.240 say by wind or something like that, or water lapping 0:12:38.280 --> 0:12:41.080 against it. Now, if you had that pieces of those 0:12:41.080 --> 0:12:44.480 pieces of rock that were in water that ultimately, over 0:12:44.559 --> 0:12:47.480 the course of years dissolved it, it would be in 0:12:47.600 --> 0:12:51.400 solution and it would no longer chemically resemble itself. That's 0:12:51.480 --> 0:12:57.079 chemical weathering. So like if you pour acid on your hand, Uh, 0:12:57.120 --> 0:13:00.480 it's gonna reconstitute into something else on the other and 0:13:00.760 --> 0:13:03.480 the hole that burns through it, the stuff ends up 0:13:03.480 --> 0:13:05.679 on the table is not really the same thing as 0:13:05.720 --> 0:13:09.120 your hand. You just chemically weathered your hand. That's a 0:13:09.160 --> 0:13:13.520 pretty extreme example. UM. And then you talked about the 0:13:13.600 --> 0:13:17.160 constant state of movement on the earth that's going on 0:13:17.200 --> 0:13:20.080 at all times. And that's basically, if you're gonna have erosion, 0:13:20.640 --> 0:13:23.360 you're gonna have a deposit somewhere. And it's just a 0:13:23.360 --> 0:13:27.600 constant cycle on the earth of weathering carried away by 0:13:27.600 --> 0:13:31.520 erosion and being put somewhere else in in cases of 0:13:31.600 --> 0:13:36.200 landslides the bottom of hills. Yeah, when we toward Guatemala, 0:13:36.240 --> 0:13:40.840 you Jerry and I and um Or I should say me, um, 0:13:40.960 --> 0:13:44.720 we we're at the site of a landslide that had happened. Um, 0:13:44.800 --> 0:13:47.320 I will never forget. Yeah, And they you know, you 0:13:47.360 --> 0:13:51.720 could still see in the sort of h jungle like forest, 0:13:51.880 --> 0:13:54.760 the swath that had been cut through years earlier, because 0:13:54.800 --> 0:13:57.800 all the stuff on either side was old growth and 0:13:57.840 --> 0:14:01.480 then the stuff through the land slide slow was Yeah, 0:14:01.480 --> 0:14:04.480 it was like it was much younger, shorter, like a 0:14:04.520 --> 0:14:07.240 different kind of green as well. And they pointed out 0:14:07.240 --> 0:14:10.319 that we were like twelve feet higher than uh basically 0:14:10.360 --> 0:14:16.320 standing on uh. Yeah, the old village they were unable 0:14:16.360 --> 0:14:20.160 to recover about two fifty people. It was really upsetting. Yeah, 0:14:20.240 --> 0:14:22.600 and I remember their children were running around, all these 0:14:22.720 --> 0:14:26.080 orphan children. Um, like they were just kind of they 0:14:26.120 --> 0:14:30.520 belonged to the remaining village. Now it was really something else. 0:14:30.680 --> 0:14:32.280 Well yeah, and just when they said, like you're like 0:14:32.280 --> 0:14:35.800 twelve feet higher than just the whole land raised up 0:14:36.280 --> 0:14:38.160 because of this month's line. It was one of those 0:14:38.160 --> 0:14:39.600 ones that like you just kind of chewed on for 0:14:39.640 --> 0:14:41.880 a little while before you finally understood like the full 0:14:41.920 --> 0:14:44.200 gravity of it. Even though like while while I was 0:14:44.240 --> 0:14:46.400 standing there, I was like, oh, this is nuts. And 0:14:46.520 --> 0:14:48.840 the more I thought about it, think the nut of 0:14:48.840 --> 0:14:53.520 your got uh So the sediment um, we we talked 0:14:53.560 --> 0:14:55.920 about the deposition at the bottom of the hill. The 0:14:55.960 --> 0:14:59.080 sediment is known as talus, right, let's the official word 0:14:59.080 --> 0:15:01.880 for it when when it's from a landslide. Yeah, yeah, 0:15:02.160 --> 0:15:05.160 that's what's being carried down. And um, with erosion, there 0:15:05.160 --> 0:15:07.480 are five different things that can act on it, which 0:15:07.520 --> 0:15:11.320 are water, which we've covered in wind and then gravity 0:15:11.360 --> 0:15:13.680 of course which we mentioned, and then waves and glaciers too. 0:15:13.960 --> 0:15:17.360 And technically gravity is a part of all of them, right, Yeah, 0:15:17.360 --> 0:15:21.320 that's true, a part of all mass movement. But um, 0:15:21.360 --> 0:15:24.800 those five agents of erosion, there are different things that 0:15:24.880 --> 0:15:30.280 can trigger a landslide or a mass movement. Um and 0:15:30.280 --> 0:15:32.000 and really if you think about it all, a mass 0:15:32.040 --> 0:15:36.280 movement is like a landslide. It's just erosion in at 0:15:36.360 --> 0:15:39.920 high speed. Sudden and high speed erosion is is basically 0:15:39.920 --> 0:15:43.240 what that is. Rather than taking millions of years to 0:15:43.320 --> 0:15:45.840 move from here to there through wind or waves or whatever, 0:15:46.320 --> 0:15:49.600 it's just happens in a moment, and it happens on mass. 0:16:03.040 --> 0:16:16.240 That's sky should all right. So we mentioned triggers, Uh, 0:16:16.880 --> 0:16:18.960 the landside always has to have a trigger, that has 0:16:18.960 --> 0:16:21.840 to be something to actually set it off, even though 0:16:22.080 --> 0:16:24.840 it maybe years and years in the making. Something finally 0:16:25.000 --> 0:16:29.720 pushes that button to make it happen. Um. It forces 0:16:29.800 --> 0:16:34.160 gravity to overcome friction, that's right. One of the things 0:16:34.360 --> 0:16:38.240 that we mentioned already in the case of Washington was water, 0:16:38.480 --> 0:16:42.600 and that is probably the most common heavy rainfall I 0:16:42.680 --> 0:16:45.240 know in California and Los Angeles. When you see houses 0:16:45.280 --> 0:16:48.040 slipping off the hill in Malibu because they don't get 0:16:48.040 --> 0:16:49.400 a lot of rain and when they do, things like 0:16:49.480 --> 0:16:53.000 that happen. Yeah, And it's either water saturating the ground 0:16:53.040 --> 0:16:55.560 and just making it so heavy that it flows downward, 0:16:56.160 --> 0:16:59.760 or it gets down in between the soil and the 0:17:00.200 --> 0:17:03.600 rock and just causes the whole thing to undermines everything 0:17:04.000 --> 0:17:08.480 either way. Water equals a lot of movement. Earthquakes that 0:17:08.560 --> 0:17:12.800 can definitely trigger a landslide. Um. We've covered earthquakes. You 0:17:12.840 --> 0:17:13.960 should go listen to that show if you have, and 0:17:14.040 --> 0:17:16.359 it's a good one. But you've got the vibrating of 0:17:16.400 --> 0:17:19.320 the Earth's crust and that UM is going to disrupt 0:17:19.359 --> 0:17:23.600 that friction pretty easily. Another big one is wildfires, which 0:17:23.640 --> 0:17:25.680 you would think, well, how would a wildfire trigger that. 0:17:25.800 --> 0:17:29.920 I'll tell you how UM. Vegetation, the roots of vegetation 0:17:30.320 --> 0:17:35.480 can lock soil into basically a totally solid, cemented state, 0:17:36.240 --> 0:17:38.919 and as long as you have thick vegetation on a slope, 0:17:39.480 --> 0:17:42.200 it's gonna be fairly stable. When a fire comes through 0:17:42.280 --> 0:17:44.800 burns out all the vegetation, it often burns the roots 0:17:44.840 --> 0:17:49.280 as well, leaving not only less stable soil, but actual 0:17:49.440 --> 0:17:52.600 pockets in that soil too, So now it's kind of pebbled, 0:17:52.920 --> 0:17:55.480 which makes it a lot more vulnerable the landslides after 0:17:55.600 --> 0:17:58.520 a wildfire. Yeah, I would I'm just guessing here, but 0:17:58.520 --> 0:18:01.960 I would guess a landslide could happen like even long 0:18:02.000 --> 0:18:05.120 after wildfire, Like if those roots die away, it would 0:18:05.119 --> 0:18:09.479 just become even less stable. Uh, and then volcanoes. Uh, 0:18:09.920 --> 0:18:12.480 volcanic action is a big cause. And there are a 0:18:12.560 --> 0:18:17.600 couple of um different kinds of flows that can contribute 0:18:17.600 --> 0:18:20.040 to a landslide from a volcano. When it's called a 0:18:20.119 --> 0:18:25.560 pyroclastic flow, and that is after your dome has collapsed 0:18:25.680 --> 0:18:29.720 or during interruption. And these are super high speed. They've 0:18:29.720 --> 0:18:34.440 clocked him at four hundred and fifty miles ad degrees fahrenheit. Yeah, 0:18:34.520 --> 0:18:38.119 lava flowing at you at four I can't even imagine that, 0:18:38.440 --> 0:18:42.400 like cage, like seven hundred and twenty four kilometers per hour, 0:18:44.040 --> 0:18:48.520 that's easier. Well, there you go. Then you just imagine four. Yeah, 0:18:48.560 --> 0:18:50.119 but I mean I don't even know what that looks like, 0:18:50.920 --> 0:18:55.520 you know, or death, yeah, exactly. Uh. And then they 0:18:55.520 --> 0:18:58.359 are something called a lahar, which is an Indonesian word. 0:18:59.119 --> 0:19:02.440 And this isn't uh it doesn't have to be during interruption, 0:19:02.720 --> 0:19:05.520 but it can be. And it is set off by 0:19:05.600 --> 0:19:09.000 water as well. Um, it's almost always near something called 0:19:09.040 --> 0:19:13.119 a stratovolcano, which are like super steep cones, and a 0:19:13.200 --> 0:19:15.280 lot of times there's either a crater lake or it's 0:19:15.320 --> 0:19:19.240 snow capped up top, and so that's the water agent. 0:19:19.920 --> 0:19:21.440 A lot of times. It's the snow and it it 0:19:21.600 --> 0:19:24.720 sort of looks like wet concrete flowing downhill. Yeah, and 0:19:24.800 --> 0:19:27.199 it may or may not be set off during an 0:19:27.240 --> 0:19:30.720 actual volcanic eruption. It can happen anytime. Yeah, and it's 0:19:30.880 --> 0:19:34.399 it's much slower, you know, an hour, but still if 0:19:34.440 --> 0:19:37.359 you're in a golf cart, you're dead. Yeah, that's a 0:19:37.400 --> 0:19:40.520 good point. Uh And while it's not fast, it has 0:19:40.760 --> 0:19:44.040 um a lot more rock. So it is one of 0:19:44.119 --> 0:19:47.480 the deadliest a lahar is I think because of just 0:19:47.640 --> 0:19:50.600 the shoot, like you can carry like a big boulder, Yes, 0:19:50.960 --> 0:19:54.479 in the middle of that wet concrete, plus of volcano also. Um, 0:19:55.119 --> 0:19:59.040 it's just it's not very stable because the composition of 0:19:59.080 --> 0:20:02.360 it is usually pretty loose rocky soil. Uh So Yeah, 0:20:02.359 --> 0:20:05.120 if you had water, it immediately turns the slurry um 0:20:05.600 --> 0:20:08.920 and when they erupt, they tend to shake the ground 0:20:08.960 --> 0:20:12.520 a little bit, which is what happened in the largest 0:20:12.640 --> 0:20:18.240 recorded landslide in Mount St. Helen's. Everybody knows the eruption, 0:20:19.480 --> 0:20:23.000 but there was actually an attendant landslide that's on YouTube 0:20:23.200 --> 0:20:24.719 you can check out. As a matter of fact, Um, 0:20:25.040 --> 0:20:29.440 we're putting a post up of just amazing landslide footage 0:20:29.960 --> 0:20:32.480 that you can check out on our website. UM, just 0:20:32.600 --> 0:20:34.160 go to stuff you Should Know dot com and check 0:20:34.200 --> 0:20:37.840 out that post. There's just a just some crazy stuff 0:20:37.840 --> 0:20:40.399 that people just happened to be filming and all of 0:20:40.480 --> 0:20:44.879 a sudden, the earth changes right before your eyes. And 0:20:45.000 --> 0:20:47.600 one of them is this Mount St. Helen's eruption, where 0:20:47.800 --> 0:20:50.920 just the whole mountain is basically just melting in front 0:20:51.000 --> 0:20:53.840 of you. I remember that one, do you know? Yeah, 0:20:54.040 --> 0:20:57.200 that was only four I was nine, so it was 0:20:57.240 --> 0:21:00.840 on my radio. Yeah. Uh, that one traveled at speeds 0:21:00.880 --> 0:21:04.200 of a hundred and fifty miles and again Washington State, 0:21:05.160 --> 0:21:08.679 not getting a break, destroyed twenty seven bridges, about two 0:21:08.760 --> 0:21:13.280 hundred homes, miles and miles of road, and covered three 0:21:13.320 --> 0:21:18.880 square miles with debris. Yeah, that was a Mount St. Helens. Well, 0:21:18.920 --> 0:21:21.600 you know, it's just the landslide. Another another frequent hazard 0:21:21.800 --> 0:21:25.320 associated with landslides is you think about it, um, when 0:21:25.400 --> 0:21:27.680 all of this earth is coming down, it's coming downward 0:21:28.680 --> 0:21:31.520 into a lower space, which is very frequently a valley, 0:21:31.880 --> 0:21:35.000 which is very frequently a river valley, which means that 0:21:35.080 --> 0:21:37.840 the river is dam now, so it's flooding behind it, 0:21:38.720 --> 0:21:41.440 right so you have a flood a flood hazard immediately, 0:21:42.080 --> 0:21:45.520 and then if that river or if that damn breaks, 0:21:46.240 --> 0:21:48.800 then you have another flood hazard down river all of 0:21:48.840 --> 0:21:51.760 a sudden too, which is something that's going on in 0:21:51.920 --> 0:21:54.880 Washington right now. Yeah, the same thing happened in Um. 0:21:55.200 --> 0:21:58.359 I think it's the most expensive landslide in US history. 0:21:58.400 --> 0:22:03.600 In thistle Utah uh in N, the same thing happened there. 0:22:03.720 --> 0:22:07.720 It damned up the Spanish Fork River and caused like 0:22:07.880 --> 0:22:10.800 much more problems just because of the flooding. And that 0:22:11.040 --> 0:22:15.639 was two hundred million dollar fix in four dollars, and 0:22:16.080 --> 0:22:18.200 that was even when Reagan was in office. So it's 0:22:18.240 --> 0:22:22.639 not too much different from the two thousand uh. The 0:22:22.920 --> 0:22:25.800 submarine landslide we should probably talk about that is in 0:22:25.880 --> 0:22:30.240 the ocean, and that is you can you can have 0:22:30.760 --> 0:22:35.880 an earthquake under the ocean triggering a landslide underwater, which 0:22:35.920 --> 0:22:39.280 will trigger a tsunami. Yeah, I can a one to 0:22:39.480 --> 0:22:43.680 three punch basically of natural disasters happening all in concert. 0:22:44.520 --> 0:22:46.560 Um that and then actually I don't know if this 0:22:46.720 --> 0:22:51.439 really technically counts, but it's seeing that um little bit 0:22:51.880 --> 0:22:57.280 triggered a memory of the Lake Penur disaster in Louisiana 0:22:57.440 --> 0:23:02.040 in night, Texico is drilling in Lake Penyr and apparently 0:23:02.119 --> 0:23:04.600 they didn't consult the map closely enough, and they were 0:23:04.640 --> 0:23:09.479 using a fourteen inch diameter drill and they drilled into 0:23:09.560 --> 0:23:12.800 the lake bottom which was on top of a salt mine, 0:23:13.320 --> 0:23:17.680 and they drilled into an operational salt mine, and the 0:23:17.880 --> 0:23:21.800 lake got sucked into the hole in the giant whirlpool. 0:23:22.640 --> 0:23:25.800 UM that took about like thirty to fifty of the 0:23:25.920 --> 0:23:29.159 surrounding acreage around the lake in into the lake with it. 0:23:29.920 --> 0:23:33.880 Eleven barges were sucked in the um flow of water 0:23:34.000 --> 0:23:36.639 reverse so it went from freshwater to salt water. It 0:23:36.840 --> 0:23:39.800 sucked the gulf into it for a second, and then 0:23:40.080 --> 0:23:42.199 a couple of days later after they were like four 0:23:42.320 --> 0:23:44.879 hundred foot geysers as like these shafts were filling with 0:23:45.000 --> 0:23:49.080 water and the air was being displaced and um, a 0:23:49.160 --> 0:23:52.000 couple of days later, after the water pressure stabilized, like 0:23:52.240 --> 0:23:54.679 nine of the barges popped back up and like went 0:23:54.760 --> 0:23:57.880 back to floating after being sucked down into this diamond mine. 0:23:57.920 --> 0:24:00.520 It's crazy and then nuts and apparently they're a aotage 0:24:00.560 --> 0:24:04.080 of it. It's it's awesome. It's like just The most 0:24:04.080 --> 0:24:06.760 amazing thing, I guess more amazing than that is no 0:24:06.880 --> 0:24:09.280 one died. Wow. Yeah, there was one guy on the 0:24:09.400 --> 0:24:13.119 lake who was operating the drill. He got all and 0:24:13.200 --> 0:24:14.800 then there was a guy fishing on the lake and 0:24:14.920 --> 0:24:17.680 he zoomed his boat to shore and made it like 0:24:17.880 --> 0:24:19.800