Latest / PlanetGeo: The Geology Podcast / Are You Karsty? Sinkholes and Karst

Transcript

Are You Karsty? Sinkholes and Karst · PlanetGeo: The Geology Podcast

• 0:02
  SPEAKER_00: Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
• 0:12
  SPEAKER_01: You have the majority of difficulties.
• 0:14
  SPEAKER_01: Let's just say that.
• 0:16
  SPEAKER_01: I'm recording.
• 0:17
  SPEAKER_01: Finally.
• 0:17
  SPEAKER_01: Thank you for coming online, Jesse.
• 0:20
  SPEAKER_01: Like my gosh, this has uh not been your morning, has it?
• 0:24
  SPEAKER_01: Chris, every morning is my morning.
• 0:27
  SPEAKER_01: What are you talking about?
• 0:28
  SPEAKER_01: Yeah.
• 0:29
  SPEAKER_01: You always give me crap about being old and having technological difficulties, but you have the majority of the problems.
• 0:34
  SPEAKER_00: Here's the thing, Chris.
• 0:36
  SPEAKER_00: I now have a trump card that I can play whenever the heck I want.
• 0:39
  SPEAKER_00: And it's the fact that you ran out of Google storage space and deleted all of your emails.
• 0:44
  SPEAKER_00: That is just you can never criticize anybody about technology ever again.
• 0:49
  SPEAKER_01: I think you've lost that right.
• 0:52
  SPEAKER_01: I don't it made sense to me.
• 0:53
  SPEAKER_01: I'm I'm like, oh my gosh, I have 15,000 cent emails that are just sitting there.
• 0:58
  SPEAKER_01: I need to get rid of them and then I needed them.
• 1:00
  SPEAKER_01: Emails are so valuable sometimes.
• 1:02
  SPEAKER_00: You gotta go back a year or two.
• 1:03
  SPEAKER_00: And when you see, it's gonna come a point where we're gonna get into a disagreement about something that happened in the past, and you're gonna want to go back and look up an email to see what happened in an exchange between you and I, and you're not gonna have any data.
• 1:17
  SPEAKER_00: And I'm gonna win the argument because I haven't and you're gonna lose because of that.
• 1:22
  SPEAKER_01: Here's what comes to my mind you restructured all of our stuff in our shared Google Drive for this, you know, this thing that we do, and you'd lost all of our scripts.
• 1:30
  SPEAKER_01: And you know how many times I've wanted to go back and look at things.
• 1:33
  SPEAKER_00: Whoa, whoa, whoa.
• 1:34
  SPEAKER_00: Uh one season, season one of scripts was the only one that got overwritten.
• 1:38
  SPEAKER_01: Well, that's a third, Jesse.
• 1:41
  SPEAKER_01: That is 33% of what we've done.
• 1:43
  SPEAKER_01: That's just gone.
• 1:44
  SPEAKER_00: Yeah, Chris.
• 1:45
  SPEAKER_00: You know what?
• 1:45
  SPEAKER_00: Here's the thing, Chris.
• 1:46
  SPEAKER_00: We're all about new stuff here at Planet Geo.
• 1:48
  SPEAKER_00: We are all about new stuff.
• 1:50
  SPEAKER_00: We don't go back and revisit the past that much.
• 1:52
  SPEAKER_00: No, that's not true.
• 1:53
  SPEAKER_00: We're talking about geology.
• 1:54
  SPEAKER_00: That is completely wrong.
• 1:55
  SPEAKER_00: I take it back.
• 1:56
  SPEAKER_00: We're talking about geology.
• 1:57
  SPEAKER_00: It's all in the past.
• 1:58
  SPEAKER_01: You know what I think?
• 1:58
  SPEAKER_01: I think you just need to start being nicer to me.
• 2:01
  SPEAKER_01: And I think other people agree.
• 2:03
  SPEAKER_00: We there has been, let's see, how do we phrase this?
• 2:06
  SPEAKER_00: There have been a couple uh emails, reviews, comments that seem to suggest I think people are a little uh defensive of you, Chris.
• 2:16
  SPEAKER_00: People are on your side, they don't like the way I treat you.
• 2:18
  SPEAKER_00: And how do you feel about that?
• 2:19
  SPEAKER_01: I think you need to do better, to be honest with you.
• 2:22
  SPEAKER_00: I'm too mean.
• 2:23
  SPEAKER_00: I mean, I know that Joyce thinks that I'm too mean to you, but yes, she does not refer to you as the good doctor anymore.
• 2:30
  SPEAKER_00: Did you know that?
• 2:31
  SPEAKER_01: No, I'm the bad doctor now.
• 2:34
  SPEAKER_01: You're just I don't know.
• 2:35
  SPEAKER_01: She just stopped saying doctor now.
• 2:37
  SPEAKER_01: She just calls you Jesse.
• 2:39
  SPEAKER_01: She doesn't refer to you, she doesn't give you the title anymore.
• 2:41
  SPEAKER_00: I've lost some respect in the from the the Boheis household.
• 2:44
  SPEAKER_00: Wow, interesting.
• 2:45
  SPEAKER_00: Okay, I really gotta I gotta tighten up around here, I guess.
• 2:47
  SPEAKER_00: Okay.
• 2:48
  SPEAKER_00: I think so.
• 2:48
  SPEAKER_00: Here we go.
• 2:49
  SPEAKER_01: Oh, hey, there's another funny thing too.
• 2:50
  SPEAKER_01: I gotta tell you this, this just popped into my head.
• 2:53
  SPEAKER_01: One of my students said, Mr.
• 2:55
  SPEAKER_01: Boy, I found your podcast, and we've been listening to it, and that because this family travels quite a bit, you know, so they'll go on big road trips and so on.
• 3:03
  SPEAKER_01: And he said, So we listened to it when we're on these road trips, and I said, Well, hold on though, but you do understand, right?
• 3:08
  SPEAKER_01: There's some swearing in it.
• 3:10
  SPEAKER_01: And he's like, Oh, yeah, yeah, I know that.
• 3:12
  SPEAKER_01: But that's usually Jesse that does the swearing.
• 3:17
  SPEAKER_00: Wow.
• 3:18
  SPEAKER_00: Yeah, I want to.
• 3:18
  SPEAKER_00: We need to go back through our our transcripts here.
• 3:21
  SPEAKER_00: I is that true?
• 3:23
  SPEAKER_00: Maybe it is true.
• 3:23
  SPEAKER_00: I don't know.
• 3:24
  SPEAKER_01: It just happened.
• 3:24
  SPEAKER_01: This was funny.
• 3:25
  SPEAKER_01: I think this was just two days ago that he brought the and we haven't talked since then.
• 3:29
  SPEAKER_00: Wow, you know what?
• 3:29
  SPEAKER_00: I'm starting to get a reputation here.
• 3:31
  SPEAKER_00: What the heck?
• 3:31
  SPEAKER_00: Okay, here's what I need.
• 3:33
  SPEAKER_00: If you're listening to this and you're on Team Jesse and not Team Chris, you need to send us an email.
• 3:37
  SPEAKER_01: Don't do this.
• 3:37
  SPEAKER_01: We do not need to be pitting people up against you and I.
• 3:40
  SPEAKER_01: I know, I know.
• 3:41
  SPEAKER_01: You and I are really, really good friends, and we like to rip on each other, and that's just the way it is.
• 3:47
  SPEAKER_00: That's just the way it is.
• 3:48
  SPEAKER_00: That's right.
• 3:48
  SPEAKER_00: It's all with love.
• 3:49
  SPEAKER_00: That's exactly right.
• 3:50
  SPEAKER_00: So today, Chris, this is a uh this is a little bit of a follow-on from our disappearing streams episode because we talked about disappearing streams, we talked about how we came about it from two very different sort of mindsets or different categorization schema of what a disappearing stream was.
• 4:07
  SPEAKER_00: But as part of that, we really focused in on karst.
• 4:11
  SPEAKER_00: And I think we didn't do a great job of really nailing the definition of karst.
• 4:17
  SPEAKER_00: And so karst is K-A-R-S-T.
• 4:20
  SPEAKER_00: That's the word we're saying, karst.
• 4:22
  SPEAKER_00: And that is a uh sort of a type of really topography that's controlled by the underlying geology.
• 4:28
  SPEAKER_00: And part of karst is sinkholes.
• 4:30
  SPEAKER_00: At least that's what I always think of when somebody mentions karst to me.
• 4:33
  SPEAKER_00: Immediately my mind goes to sinkholes.
• 4:36
  SPEAKER_00: And I talked about how I live in Pennsylvania in this karst area, and we just had a sinkhole open up on campus, like right near a big parking deck.
• 4:43
  SPEAKER_00: Uh, that was a little while ago now.
• 4:45
  SPEAKER_00: But you know, sinkholes happen.
• 4:46
  SPEAKER_00: Sinkholes are uh not an uncommon thing in the state college, the the central Pennsylvania area.
• 4:53
  SPEAKER_00: And so this is kind of a little bit of a follow-on episode to describing that aspect.
• 4:58
  SPEAKER_01: That's right.
• 4:59
  SPEAKER_01: When I think of karst versus sinkholes, I think of sinkholes as more singular, where you can have something happens and it collapses down in itself.
• 5:08
  SPEAKER_01: And we're gonna talk about the different ways that this can happen as we progress through this episode.
• 5:12
  SPEAKER_01: And I think of karst as more of a this is not singular, it's more the topography is dominated by many, many, many sinkholes.
• 5:22
  SPEAKER_01: That's how I think of karst versus sinkholes.
• 5:24
  SPEAKER_00: And you're exactly right, Chris.
• 5:25
  SPEAKER_00: That is the the aspect of karst that sinkholes is one part of a karst topography.
• 5:31
  SPEAKER_00: You can have caves, you can have disappearing streams.
• 5:33
  SPEAKER_00: All of those go together in the the karst bin.
• 5:36
  SPEAKER_00: The features that define karst topography are sinkholes, caves, disappearing streams, lots of groundwater, surface water interaction.
• 5:44
  SPEAKER_01: Okay.
• 5:44
  SPEAKER_01: So, Jesse, the premise of this whole thing that we do here, this Planet Geo podcast is why geoscience should matter to everyone else.
• 5:54
  SPEAKER_01: So I'm gonna throw this out at you.
• 5:57
  SPEAKER_01: Why are we talking about sinkholes then?
• 5:59
  SPEAKER_01: If this is something that matters, it has societal relevance.
• 6:03
  SPEAKER_01: You need to support that, I think.
• 6:05
  SPEAKER_01: You gotta you gotta sell that to our listeners then.
• 6:08
  SPEAKER_00: So uh this is an interesting aspect of, and that one of the main benefits I have gained from doing this podcast with you is not only that we get to hang out more, which is great and very fun, but also I sort of pay attention to different stuff than I used to before we started doing this podcast.
• 6:22
  SPEAKER_00: So we talked about Karst and Disappearing Streams a couple weeks ago now.
• 6:26
  SPEAKER_00: There was an article in the AGU sort of publication sphere in the EOS magazine.
• 6:32
  SPEAKER_01: The American Geophysical Union.
• 6:34
  SPEAKER_01: That's what AGU is.
• 6:35
  SPEAKER_00: Yeah, so you know, geoscientists um in the US that they have published an article on a research article, and basically this was a publication that made a map of sinkhole susceptibility across the United States.
• 6:47
  SPEAKER_00: So I clicked on this, I would have not clicked on this three years ago.
• 6:51
  SPEAKER_00: Definitely would not have.
• 6:52
  SPEAKER_00: I would have been like, oh, whatever.
• 6:53
  SPEAKER_01: That is such a good point, Jesse, and so true.
• 6:57
  SPEAKER_01: I also view the world around me very differently because we do this podcast together.
• 7:04
  SPEAKER_01: I I don't know.
• 7:04
  SPEAKER_01: It's uh that's such a good point.
• 7:06
  SPEAKER_01: I I guess I never really deliberately or consciously thought about that, but when you said it, I automatically thought, that is so true.
• 7:14
  SPEAKER_01: I look at everything differently.
• 7:17
  SPEAKER_01: It's kind of like when I was brewing a lot of beer, you know, I got really good at it, and I couldn't.
• 7:23
  SPEAKER_01: You got really good at it.
• 7:24
  SPEAKER_00: You there was a strawberry wheat beer that you made for a while.
• 7:27
  SPEAKER_00: Strawberry wheat, right?
• 7:28
  SPEAKER_00: Is that right?
• 7:29
  SPEAKER_00: Yeah, strawberry wheat or cherry wheat, cherry wheat, strawberry wheat.
• 7:32
  SPEAKER_01: I made it all because I couldn't look at anything.
• 7:35
  SPEAKER_01: I Jesse, I was looking at everything, thinking to myself, I wonder if I can ferment that.
• 7:41
  SPEAKER_01: Like that seriously, if I'd go through the grocery store and I'd be like, I can ferment that.
• 7:46
  SPEAKER_01: I know I can.
• 7:47
  SPEAKER_01: And then I would just play around with it, right?
• 7:49
  SPEAKER_01: So I haven't brewed hardly anything since we started doing this podcast because I just don't have time.
• 7:56
  SPEAKER_01: And this chews up, this takes a really a lot of time to do.
• 8:00
  SPEAKER_01: Absolutely.
• 8:01
  SPEAKER_01: So I've transitioned now to thinking about the geologic world completely differently, but it's like I used to work view the brewing world, you know.
• 8:10
  SPEAKER_01: I couldn't lie, it just affected my whole Yeah, just the total outlook.
• 8:13
  SPEAKER_00: And so I click on things because I feel strongly, and you we've talked about this, we were just talking about this before we hit record.
• 8:19
  SPEAKER_00: What is the societal relevance?
• 8:21
  SPEAKER_00: Like, you know, that is a big component of what we're trying to do here.
• 8:24
  SPEAKER_00: And so you and I both feel we have to defend that statement a lot, right?
• 8:28
  SPEAKER_00: And so if there's any press article or news article or new thing that sort of is in that space where, hey, somebody did something interesting in geoscience, and here's why it matters, I'm gonna click on that in a way that I really didn't before.
• 8:40
  SPEAKER_00: I was super interested in just you know, igneous petrology, and uh, so it's a really interesting exercise.
• 8:45
  SPEAKER_00: Anyway, uh to come back to that.
• 8:46
  SPEAKER_01: Hold on, hold on.
• 8:47
  SPEAKER_01: I'm gonna interrupt you a second, Jesse, because in a previous episode, you asked me about how I approach my students in terms of relevance and what you teach, right?
• 8:58
  SPEAKER_01: Because I especially with my freshmen, these 14, 15-year-old kids, they're taking an earth science class where we study the planet and how it works and why it should matter to them, right?
• 9:09
  SPEAKER_01: And you asked if I do that differently now because of things that we've done on this podcast and the series about critical elements and rare earth elements and all these things.
• 9:17
  SPEAKER_01: So just this past week, then I began to talk about rocks and the rock cycle.
• 9:24
  SPEAKER_01: And I'm using that as a launching pad to talk about our resources then, because I think you have to do it in that order, right?
• 9:30
  SPEAKER_01: You can't talk about resources before you've talked about minerals, rocks, and the rock cycle, right?
• 9:36
  SPEAKER_01: It just that has to be the pedagogy.
• 9:38
  SPEAKER_01: So I pick out four rocks that I think are just I I take them off my shelves, you know, and I think they're awesome.
• 9:45
  SPEAKER_01: And I tell them the story of these rocks, you know, how they formed and and what they mean and the process of discovery that went into telling this story, right?
• 9:56
  SPEAKER_00: Let me interrupt you real quick and just paint a visual because you know, Chris, the Chris Bullheist classroom, at least the old classroom used to be, and I think you still have this, is this beautiful like bookshelves, like big glass door, floor-to-ceiling bookshelves with rocks in them, just full of rocks.
• 10:10
  SPEAKER_00: I mean, you have an impressive rock collection there and mineral collection as well.
• 10:13
  SPEAKER_00: And so you're pulling these things out, handing them around, and describing.
• 10:16
  SPEAKER_00: I mean, that's just the visual here in classes.
• 10:18
  SPEAKER_00: It was to the right of the students sitting in your old classroom when I was taking your class.
• 10:23
  SPEAKER_00: Oh, yeah.
• 10:23
  SPEAKER_00: It was that big bookshelf all to the right.
• 10:25
  SPEAKER_00: I mean, basically the entire sort of square classroom, the right side was all rocks in these floor-to-ceiling bookshelves with glass panes so you could see into them.
• 10:33
  SPEAKER_00: It was beautiful.
• 10:34
  SPEAKER_01: So in my new classroom, we moved in 2014 into this new building, and they they custom designed just for me.
• 10:42
  SPEAKER_01: I'm the only science teacher that has these.
• 10:45
  SPEAKER_01: It's the same thing: floor-to-ceiling, glass shelved, glass doors.
• 10:50
  SPEAKER_01: It encases my entire lab area.
• 10:53
  SPEAKER_01: So I have a classroom area and a lab area, and so it's it's a little bit of a different setup, but it is it's spectacular.
• 11:00
  SPEAKER_01: So you're right.
• 11:00
  SPEAKER_01: That's exactly I pulled out of there.
• 11:02
  SPEAKER_01: I just picked four rocks and I talked about them.
• 11:05
  SPEAKER_01: But at the end, I said, listen, this is this is the story of these rocks, and this is why I'm so passionate about what I teach, because these stories are pretty cool.
• 11:14
  SPEAKER_01: And the kids they they agreed, like the yeah, that's pretty awesome, it's boys.
• 11:18
  SPEAKER_01: But in addition to that, I talked about things that I probably wouldn't have talked about if it weren't for this podcast.
• 11:24
  SPEAKER_01: I I talked about the rare earth elements, the importance of lithium, and the importance of copper and vanadium, these things that we're talking now about things that weren't even on people's tongues ten years ago.
• 11:37
  SPEAKER_00: You know, it's just such a different world we're we're sort of living in, and and uh I think you and I are gaining exposure to that through doing this podcast.
• 11:46
  SPEAKER_00: I mean, we kind of are we we sort of have to pay attention to a different, a different and growing and important cross-section of our field that maybe we we didn't pay as much attention to.
• 11:54
  SPEAKER_00: I I'd love to have a longer conversation about this, about how this like brave new world that I think is happening right now, how do we incorporate that into the classrooms better?
• 12:02
  SPEAKER_00: I think it'd be a really interesting conversation to have with you and I certainly and and maybe somebody else to bring on who can help talk about this, because I've certainly done it and continue to do it differently throughout the semester this year than I did last year and the year before that as well.
• 12:17
  SPEAKER_00: Because as you said, real quick, last tangent, and then we'll get to syncles and cars.
• 12:22
  SPEAKER_00: Because the story's in the rocks, that's why we're kind of talking about this.
• 12:24
  SPEAKER_00: The story is in the rocks here, but as you said, you have to talk about the rock cycle and minerals and plate tectonics before you can start to talk about the societally relevant aspects here, because otherwise it's just not gonna make any sense, right?
• 12:36
  SPEAKER_00: Like if you're talking about lithium pegmatites, you you gotta understand a little bit about ignorance petrology to get to that point.
• 12:42
  SPEAKER_00: So, in the you know, the normal structure of a class in a textbook too, is all this like societally relevant, interesting stuff gets put in the back, like the last couple chapters, because you have to have all the basics, the basic framework in place before you start to talk about lithium pegmatites, right?
• 12:59
  SPEAKER_00: And I always did I never got there.
• 13:01
  SPEAKER_00: The last like four years I've taught this intro to geology class.
• 13:04
  SPEAKER_00: I rarely like get to it because I I take too long to get to the end of the semester.
• 13:08
  SPEAKER_00: So by the end of the semester hits, like I'm like, okay, glaciers, we're we're gonna end on glaciers this year.
• 13:13
  SPEAKER_00: We're not getting to the like interesting stuff.
• 13:15
  SPEAKER_00: But this year I decided I'm gonna sort of you know spin copper, take one of them that's important and try and tell the story in pieces as we go along.
• 13:25
  SPEAKER_00: So I started telling this, you know, in the how the solar system formed and what copper is in there.
• 13:29
  SPEAKER_00: Anyway, trying to like weave it into the story more, but I don't know that that's right educationally.
• 13:35
  SPEAKER_01: I absolutely think it's right.
• 13:36
  SPEAKER_01: I think you actually need to move your discussion about resources to the front end of your curriculum.
• 13:41
  SPEAKER_00: Totally.
• 13:42
  SPEAKER_00: About why they matter and then build the knowledge base on that for sure.
• 13:46
  SPEAKER_00: For sure.
• 13:46
  SPEAKER_01: Um, I kind of frame it with my kids.
• 13:48
  SPEAKER_01: I I was just talking about this, and and again, then we'll get to sinkholes, but it's like kind of like knowing where your food comes from.
• 13:54
  SPEAKER_01: I think that that's important.
• 13:55
  SPEAKER_01: And the same applies to resources.
• 13:57
  SPEAKER_01: We need to know where these things come from.
• 13:59
  SPEAKER_01: Where does your iPhone come from?
• 14:01
  SPEAKER_01: Absolutely.
• 14:02
  SPEAKER_00: Where does your where does your computer come from?
• 14:04
  SPEAKER_00: It's super important.
• 14:05
  SPEAKER_00: I totally agree.
• 14:06
  SPEAKER_00: And it's something that we, as geologists and geoscientists, have not done a good job on for the last 20 years, and it's super important that we do right now.
• 14:15
  SPEAKER_00: I mean, now is the time.
• 14:16
  SPEAKER_00: It is clearly important.
• 14:18
  SPEAKER_00: It's a brave new world as far as like the implications of geoscience, and we have to do a better job of it.
• 14:22
  SPEAKER_00: So, with that segue, do I get the segue word?
• 14:26
  SPEAKER_00: No, not quite.
• 14:27
  SPEAKER_00: But with that segue, sinkholes.
• 14:29
  SPEAKER_00: Okay, here's the here's like one statistic of of many that we could use, but there's been these resource assessments for like hold on, gotta stop you just for a second because I it's been a long time since I asked the original question.
• 14:43
  SPEAKER_01: Why are sinkholes?
• 14:44
  SPEAKER_01: Well, that was a quite a tangent we went on there, Chris.
• 14:46
  SPEAKER_01: I mean, geez.
• 14:47
  SPEAKER_01: I know, but that's okay.
• 14:48
  SPEAKER_01: It's our podcast, and we can do what we want.
• 14:50
  SPEAKER_01: Yeah, that's right.
• 14:51
  SPEAKER_01: That's right.
• 14:51
  SPEAKER_01: Why are sinkholes relevant to society?
• 14:54
  SPEAKER_00: Okay, so here's just a couple numbers for this.
• 14:56
  SPEAKER_00: And again, we're gonna be a little US-centric here because that's where we live, and again, it's our podcast.
• 15:00
  SPEAKER_00: In 1997, FEMA, the Federal Emergency Management Agency, we've all heard of FEMA, I think, but suggested, or that there's been this number that's put out there that in the US, sinkhole losses, so sort of economic losses due to sinkholes, was on the order of like 125 million per year, or some other estimates by the USGS around that time, late 90s, was like 300 million a year.
• 15:21
  SPEAKER_00: So that's kind of been the number that people use, which is a big number, right?
• 15:24
  SPEAKER_00: That surprised me, that number.
• 15:26
  SPEAKER_00: But the USGS in this recent publication just calculated that Florida alone had nearly$1.5 billion in losses due to sinkholes just in the last five years.
• 15:36
  SPEAKER_00: So Florida alone, over five years, was getting a yearly rate higher than that.
• 15:41
  SPEAKER_00: So, like it matters, and we and I think it's a representation that we don't quite know how much it matters.
• 15:46
  SPEAKER_00: How important are sinkholes?
• 15:47
  SPEAKER_00: We they're clearly those are big numbers, but how important kind of are they?
• 15:51
  SPEAKER_00: And so we're gonna sort of structure this conversation about the geology of sinkholes a little bit around a recent sort of map that was made by USGS geologists that tried to quantify this or predict this a little bit better and produced what's called a sinkhole susceptibility index across the US and sort of say, okay, where is it important to pay attention to sinkholes?
• 16:11
  SPEAKER_01: That's right.
• 16:12
  SPEAKER_01: It which brings up the point that every one of the 48 contiguous states plus Washington, DC, have areas that are likely for sinkhole development.
• 16:22
  SPEAKER_00: Chris, which that I think it just intuitively surprised me.
• 16:26
  SPEAKER_00: Because again, I think sinkholes, I think karst.
• 16:29
  SPEAKER_00: And you think karst, you think those of you that are geologists will think, you know, Tennessee, Kentucky, Pennsylvania, places where there's a lot of carbonate rocks, a lot of rain, karsty areas, places where there's caves, right?
• 16:39
  SPEAKER_00: Where are there caves?
• 16:40
  SPEAKER_00: Okay, that's where sinkholes are probably forming.
• 16:42
  SPEAKER_01: Did you just invent a word right there?
• 16:44
  SPEAKER_01: You just said karsty.
• 16:45
  SPEAKER_01: Karsty.
• 16:46
  SPEAKER_00: Yeah, that's a good one, right?
• 16:47
  SPEAKER_00: I like it.
• 16:49
  SPEAKER_00: I knew what you meant.
• 16:49
  SPEAKER_00: It's a good one.
• 16:50
  SPEAKER_00: Chris, are you karsty?
• 16:51
  SPEAKER_00: Are you karsty?
• 16:53
  SPEAKER_00: And and the good news is we could sell t-shirts in all of the lower 48 states because everybody's karsty.
• 17:00
  SPEAKER_00: I'm not karsty.
• 17:01
  SPEAKER_00: I might be crusty, but yeah.
• 17:04
  SPEAKER_00: So Chris, I uh they're kind of every or these sinkholes are everywhere.
• 17:07
  SPEAKER_00: But how I think it let's talk about how sinkholes operate and what forms them.
• 17:11
  SPEAKER_00: So how do sinkholes form?
• 17:13
  SPEAKER_00: Just like frame this for us, how they form.
• 17:15
  SPEAKER_01: I can do that because you said these what three or four states you listed off.
• 17:20
  SPEAKER_01: You said Kentucky and Tennessee and Florida and even Missouri because of these carbonate rocks.
• 17:26
  SPEAKER_01: And and those are typical karst uh formations, right?
• 17:31
  SPEAKER_01: But there's another kind of karst that's called pseudo-karst.
• 17:36
  SPEAKER_01: So we have we have these like traditional where you have rocks that are getting dissolved.
• 17:42
  SPEAKER_01: If you think about this, then if you have like, let's say, limestone, subsurface limestone, and groundwater that's slightly acidic is flowing through this, it's selectively dissolving the limestone, opening up cavities, and over time, these cavities can get big enough where collapse happens, if especially if they're really near the surface, right?
• 18:01
  SPEAKER_01: Then it's easy for collapse to happen.
• 18:03
  SPEAKER_00: That's a good point, Chris.
• 18:04
  SPEAKER_00: Let me just sort of double-click on this or frame this a minute.
• 18:07
  SPEAKER_00: Karst is a topography type.
• 18:09
  SPEAKER_00: So it has features like caves, sinkholes, disappearing streams.
• 18:13
  SPEAKER_00: We're talking about sinkholes specifically, how sinkholes form.
• 18:16
  SPEAKER_00: And you're pointing out that there's there's karst and there's pseudocarst, and those are like a topography type or a category, but sinkholes are one component of those things, and there's multiple ways that sinkholes can form.
• 18:27
  SPEAKER_00: So sorry to interrupt there.
• 18:28
  SPEAKER_00: I just wanted to make sure we're kind of on the same high-level page there of what this are.
• 18:32
  SPEAKER_00: So karst is dissolving rocks, like you said, right?
• 18:36
  SPEAKER_00: It's dissolving carbonate, and water is very good at dissolving things like marble or calcite or limestone or dolostone.
• 18:45
  SPEAKER_00: We talked about that in a previous episode.
• 18:47
  SPEAKER_00: Water is really great at dissolving those things.
• 18:50
  SPEAKER_01: That's right.
• 18:50
  SPEAKER_01: And there are two kinds of karst or sinkhole formation.
• 18:55
  SPEAKER_01: One is called sufosion, or it's this kind of gradual subsidence sinkhole, or as you probably would call it, you'd probably call it subsidence because you gotta be fan, you gotta take every opportunity to be fancy.
• 19:10
  SPEAKER_01: That's right.
• 19:10
  SPEAKER_01: And this kind of sinkhole formation is is not dramatic, it's not very sexy at all, because it's it's just this kind of slow process whereas water trickles down, it carries not only the water with it, but sediment with it, and it can form this kind of gradual, slow, monotonous.
• 19:27
  SPEAKER_01: It's kind of like soil creep, if you will.
• 19:30
  SPEAKER_01: Exactly, Chris.
• 19:31
  SPEAKER_00: It's it's slow, and it, you know, you worry about it, you gotta know if it's gonna happen when you're like building a building.
• 19:36
  SPEAKER_00: You don't want to build your building there, but it's not like gonna, it's not gonna kill you.
• 19:39
  SPEAKER_00: You're not gonna fall into it because it's super slow, and it's kind of this bowl-shaped depression, I suppose.
• 19:44
  SPEAKER_00: So that's number one type of sinkhole.
• 19:46
  SPEAKER_01: And the other one is much more dramatic.
• 19:48
  SPEAKER_01: This is a sudden collapse sinkhole, and this this can be deadly, it can be it's kind of a violent sort of event, right?
• 19:54
  SPEAKER_01: Where it happens catastrophically, and it's the most damaging kind, it's the most concerning kind, and uh geologically it's it's the coolest kind also.
• 20:03
  SPEAKER_00: Yeah, right, it's true.
• 20:04
  SPEAKER_00: It it can be yeah, very fascinating.
• 20:07
  SPEAKER_00: So the way to think about that cover collapse one is basically you have like a rigid roof over your cave, and the roof of the cave collapses, which you know, obviously, if you're standing on the surface, when that thing collapses, you're you're gonna fall into the cave, right?
• 20:19
  SPEAKER_00: That's kind of the idea.
• 20:20
  SPEAKER_00: It's rapid.
• 20:21
  SPEAKER_00: It can be really traumatic, you think of immediately happening, but it can happen over the course of a couple days, and it's slumping, and the whole thing is kind of falling in, and that would still be a cover collapse sinkhole.
• 20:30
  SPEAKER_00: It is falling into a void.
• 20:32
  SPEAKER_00: The ground is falling into a cavity, an open cavity that used to be stable and is not now.
• 20:38
  SPEAKER_01: And this brings up uh kind of a side tangent.
• 20:41
  SPEAKER_01: So give me a little bit of leeway here.
• 20:43
  SPEAKER_01: One of my favorite rocks is look at how nice I'm being to you.
• 20:47
  SPEAKER_00: I'm giving you leeway.
• 20:48
  SPEAKER_00: I know that would be a good one.
• 20:50
  SPEAKER_01: Very polite.
• 20:51
  SPEAKER_01: How nice of me.
• 20:52
  SPEAKER_01: Thank you.
• 20:52
  SPEAKER_01: Yeah, one of my favorite rocks is a rock called Brecia.
• 20:55
  SPEAKER_01: And it's B-R-E-C-C-I-A.
• 20:58
  SPEAKER_01: So it's a very mispronounced word.
• 21:00
  SPEAKER_01: A lot of my students will call it Breccia, and I'm like, no, it's like you breccia, you know, with a chu.
• 21:06
  SPEAKER_01: I love this rock because it's it's a lot like conglomerate.
• 21:08
  SPEAKER_01: It's it's made up of large, high energy clasts, but Breccia is different from conglomerate in that it's made up of angular clasts.
• 21:16
  SPEAKER_01: And to any budding geologist, you quickly learn that angularity when it you're talking about pieces that are in a rock means that it hasn't been transported very much or very far.
• 21:27
  SPEAKER_01: It's high energy because they're large, but they're angular and sharp and jagged, and so they haven't they formed very quickly without a lot of transport, right?
• 21:36
  SPEAKER_01: So up in the upper peninsula, there is limestone near the surface that has collapsed and it forms this kind of collapse brecia.
• 21:45
  SPEAKER_00: Does that make sense?
• 21:45
  SPEAKER_00: Yeah, yeah, yeah.
• 21:47
  SPEAKER_00: This is really cool rock.
• 21:48
  SPEAKER_00: It's a beautiful rock.
• 21:49
  SPEAKER_00: I remember we saw one of these.
• 21:51
  SPEAKER_00: I'm not sure if this is I I I seem to remember this is going back to my undergrad days, but I saw one of these in um a field trip in Death Valley in the United States, where there's this.
• 22:00
  SPEAKER_00: Mega breccia, which the blocks, the pieces of breccia, the angular blocks of rock are like the size of a car.
• 22:06
  SPEAKER_00: And it's cemented with calcite.
• 22:08
  SPEAKER_00: And so what fills in the gap is calcite, calcium carbonate.
• 22:12
  SPEAKER_00: And I seem to remember there being a bit of a debate about how this mega breccia in the in Death Valley actually formed.
• 22:18
  SPEAKER_00: But this is one good way to form it.
• 22:20
  SPEAKER_00: Is imagine this is a great point, Chris.
• 22:22
  SPEAKER_00: This is a super cool rock.
• 22:23
  SPEAKER_00: And imagine you have a roof of a cave that collapses down in.
• 22:27
  SPEAKER_00: The roof pieces of rock are going to be angular, they're going to fall into a big pile at the bottom of the cave.
• 22:33
  SPEAKER_00: And then what do you have in caves?
• 22:35
  SPEAKER_00: You have stalactites and stalagomites forming.
• 22:37
  SPEAKER_00: You're having water that is enriched in calcite, basically, percolating through there and precipitating calcite in between the rocks, and then it's kind of melding them together in a way and forming this beautiful breccia.
• 22:48
  SPEAKER_00: Is that the way that this rock in the UP was formed?
• 22:51
  SPEAKER_01: It is exactly how this rock in the UP formed.
• 22:53
  SPEAKER_01: So it's called beautiful rock breccia.
• 22:55
  SPEAKER_00: Collapse breccia, okay, yeah.
• 22:57
  SPEAKER_01: And what I love about it is that the story is so well laid out.
• 23:00
  SPEAKER_01: You can hold the rock in your hand and you can just see how this formed, especially if you're on site, right?
• 23:06
  SPEAKER_01: You're at the outcrop.
• 23:07
  SPEAKER_01: You can see the outline of the cave that the rock collapsed into.
• 23:11
  SPEAKER_01: What I love about Breccia is the story that it tells, right?
• 23:14
  SPEAKER_01: It comes back to it always comes for me, it always comes back to that.
• 23:17
  SPEAKER_01: So anyway, let's get back on track.
• 23:19
  SPEAKER_00: You gave me some leeway.
• 23:21
  SPEAKER_00: I like it.
• 23:21
  SPEAKER_00: That's a I mean, it's a beautiful rock.
• 23:23
  SPEAKER_00: I don't think I've seen the one in the UP you're talking about.
• 23:25
  SPEAKER_00: You have.
• 23:25
  SPEAKER_00: I have.
• 23:26
  SPEAKER_00: Oh, we saw it on the field trip.
• 23:27
  SPEAKER_00: Okay.
• 23:28
  SPEAKER_00: I don't uh I was too obsessed with the veins in the in the you know on the shore of Lake Michigan and cross-cutting relationships to figure that one out.
• 23:35
  SPEAKER_00: But these things are really pretty rocks because they get cemented with calcite, and so you have this sort of white cement that's bonding them together.
• 23:42
  SPEAKER_00: But one important thing about karst, so okay, sinkholes are one part of what we call karst topography.
• 23:48
  SPEAKER_00: Karst topography, again, is formed in areas where there is dissolvable rock.
• 23:54
  SPEAKER_00: So there's rock being dissolved, what is creating these cavities underneath of the ground?
• 23:58
  SPEAKER_00: We've really hit on that point.
• 24:00
  SPEAKER_00: So that's what karst is.
• 24:01
  SPEAKER_00: And it's an important statistic here that around 20% of the U.S.
• 24:05
  SPEAKER_00: is underlain by karst landscapes, which is way more than I would have guessed.
• 24:10
  SPEAKER_00: That's a lot, right?
• 24:11
  SPEAKER_00: It's almost like a fifth of the U.S.
• 24:13
  SPEAKER_00: is underlain by karst.
• 24:14
  SPEAKER_01: Question for you Does that stat include all karst?
• 24:18
  SPEAKER_01: Does it include pseudo-karst as well, which we'll get into here in just a minute?
• 24:22
  SPEAKER_00: No, I don't think so.
• 24:23
  SPEAKER_00: That is just karst, like dissolvable rock underneath there.
• 24:27
  SPEAKER_00: And 40%, another mind-blowing stat, 40% of the groundwater used for drinking in the US comes from karst aquifers.
• 24:35
  SPEAKER_00: That blew me away.
• 24:37
  SPEAKER_00: That is so much.
• 24:38
  SPEAKER_00: 40% is a lot.
• 24:40
  SPEAKER_00: Okay, so that's karst.
• 24:42
  SPEAKER_00: Dissolvable rock, you get sinkholes, you get caves, you get disappearing streams.
• 24:45
  SPEAKER_00: What is pseudo-karst?
• 24:47
  SPEAKER_00: Geologists are not great at naming things in a really creative way.
• 24:49
  SPEAKER_00: So pseudo-carst, right?
• 24:51
  SPEAKER_00: I mean, it's a cool name, but it's it's a little confusing.
• 24:54
  SPEAKER_01: I don't know.
• 24:55
  SPEAKER_01: I like it.
• 24:56
  SPEAKER_01: I mean, you're a little pseudo-intellectual, so you know.
• 25:01
  SPEAKER_00: Well done.
• 25:02
  SPEAKER_00: That was a good one.
• 25:02
  SPEAKER_00: I love that was quite good, Christopher.
• 25:06
  SPEAKER_00: Well done, Cooper.
• 25:08
  SPEAKER_00: You're on, you're uh, you're in Fuego today.
• 25:10
  SPEAKER_00: Nicely done.
• 25:10
  SPEAKER_01: Thank you.
• 25:11
  SPEAKER_01: Thank you.
• 25:11
  SPEAKER_01: Pseudo means false.
• 25:13
  SPEAKER_01: And so this is a different kind of karst.
• 25:16
  SPEAKER_01: Let me I think the best way to explain this is just by going over some examples of it.
• 25:20
  SPEAKER_01: Pseudocarst can be, let's say, volcanic caves, which are usually lava tubes, right?
• 25:26
  SPEAKER_01: If you can let me just go through this a second real quick.
• 25:29
  SPEAKER_01: But if you can imagine a very thick lava flow, let's say a 30-foot thick lava flow that comes out of a vent of a volcano, and what happens then is the surface, the part of the lava that's in contact with the air cools the fastest, right?
• 25:42
  SPEAKER_01: That just intuitively makes sense.
• 25:44
  SPEAKER_01: Cools from the outside in.
• 25:46
  SPEAKER_01: Well, what you're left with then, with this really thick lava flow, is the central part of that lava flow is insulated by all of the rock that's already solidified.
• 25:56
  SPEAKER_01: And so it stays molten much, much longer.
• 26:00
  SPEAKER_01: It's not going to cool.
• 26:01
  SPEAKER_01: It's it's kind of like putting hot water into a thermos versus just an open mug.
• 26:05
  SPEAKER_01: It's going to stay hotter longer, right?
• 26:07
  SPEAKER_01: So what the the lava then will flow through this insulated tube, and eventually it gets to the edge of the lava flow where the lava just kind of comes up and out.
• 26:16
  SPEAKER_01: And what this does is it allows these kinds of volcanoes to sprawl laterally, right?
• 26:22
  SPEAKER_01: I always think of like Hawaiian type eruptions.
• 26:25
  SPEAKER_00: Hey, Chris, let me interrupt real quick, because the, you know, I think people might have seen these videos when when Kilauea or something is erupting, you'll see the volcanic centers at the middle of the island, but you'll see these videos of lava dumping into the ocean.
• 26:40
  SPEAKER_00: And that's because lava tubes are transporting that stuff just slightly underneath the surface in a molten form all the way out to the flanks of the volcano, which are out on the uh you know out on the coast, basically.
• 26:52
  SPEAKER_00: So lava can go a long, long ways in these lava tubes, a long way.
• 26:57
  SPEAKER_01: I think Jesse, didn't I take you to into a lava tube and the moon to do that?
• 27:03
  SPEAKER_00: Okay.
• 27:03
  SPEAKER_00: We did, and uh, I was I just went back to that that same one uh last year, two years ago, on our field course, our Penn State uh field course goes out there and we were wandering around the exact same ones.
• 27:13
  SPEAKER_00: And actually, this is how you get pseudocarst because the lava tube, it's not that hard to imagine.
• 27:19
  SPEAKER_00: The lava tube has a thin roof on it, a couple feet, couple meters, and that can collapse.
• 27:24
  SPEAKER_00: And actually, the way you get down into this lava tube, at least at Craters of the Moon National Monument, is you climb down one of these cover collapse sinkholes, you climb down into the sinkhole, then you're in the lava tube where upstream is a lava tube and downstream is a lava tube, and you kind of walk downstream and then you get out through another cover collapse sinkhole, and you're sort of underground for a while, and then you pop out in another uh another sinkhole.
• 27:47
  SPEAKER_00: So it's easy to envision how a sinkhole would form in this pseudocarst setting, which is not dissolving rocks, but it's it's creating cavities in the earth in a different way.
• 27:56
  SPEAKER_01: Another one that's would fall into the category of pseudocarst would be something on the order of underground sewer pipes, let's say.
• 28:04
  SPEAKER_01: This would be like an anthropogenic.
• 28:06
  SPEAKER_01: Let's say a storm sewer running underground in front of a neighborhood, and that storm sewer pipe has a crack in it.
• 28:13
  SPEAKER_01: Well, during an event, that storm sewer is just full of water.
• 28:18
  SPEAKER_01: It's over full, actually.
• 28:20
  SPEAKER_01: And so when it hits that crack, water will shoot out of the ground, carrying sediment with it, washing away sediment around the pipe, and then after the event or after several events, it can have washed away enough sediment to cause it to collapse.
• 28:35
  SPEAKER_01: I think big cities actually, this is somewhat of a problem, right?
• 28:39
  SPEAKER_01: I mean, cracked pipes are are not all that uncommon.
• 28:43
  SPEAKER_01: And then these things can develop.
• 28:45
  SPEAKER_01: I had this actually in my front yard at my old house.
• 28:47
  SPEAKER_01: Oh, yeah.
• 28:48
  SPEAKER_01: I didn't know that.
• 28:49
  SPEAKER_01: Water would shoot out of the yeah, water would shoot out of that like it, it looked like a geyser.
• 28:54
  SPEAKER_01: That's after the storms, yeah.
• 28:56
  SPEAKER_01: After the storms, I'd walk out to my front yard and and I'd have like this cone-shaped pile of just loose sand sitting right there.
• 29:04
  SPEAKER_01: Because it's coming from underneath your house.
• 29:06
  SPEAKER_01: That's right.
• 29:07
  SPEAKER_01: Well, no, it was out in front.
• 29:08
  SPEAKER_01: It was in the front yard.
• 29:09
  SPEAKER_00: Okay, but still in the front yard, yeah.
• 29:11
  SPEAKER_00: That shouldn't be on the surface.
• 29:12
  SPEAKER_00: That should not be in the road or driveway, it should be in the ground.
• 29:14
  SPEAKER_01: No, I actually had to make phone calls to the township supervisor.
• 29:18
  SPEAKER_01: Like this this took a long time to get this taken care of because people walking then, you know, alongside the road along my front yard.
• 29:25
  SPEAKER_01: I was worried about them stepping into this and breaking an ankle while it's on my property.
• 29:28
  SPEAKER_01: So that was something that I was really concerned about, actually.
• 29:30
  SPEAKER_00: Absolutely.
• 29:31
  SPEAKER_01: But this is that's a pseudo-carst kind of setting right there, too.
• 29:36
  SPEAKER_01: So an anthropogenic kind.
• 29:37
  SPEAKER_00: And a couple other different types of pseudo-carst are like tectonic features.
• 29:42
  SPEAKER_00: Think of faults or think of the San Andreas fault or or different types of faults where basically the the earth is opening up.
• 29:49
  SPEAKER_00: You can form cavities in the earth in a tectonically active scenario, usually in an extensional setting.
• 29:55
  SPEAKER_00: So not at a plate margin where there's convergence going on or subduction or continent collision, but in an extensional setting, you can open up cavities in the earth this way.
• 30:04
  SPEAKER_00: And one interesting one, Chris, was talus caves.
• 30:07
  SPEAKER_00: So think of a mountainside and you have this talus slope where the rocks are falling down, big boulders are falling down.
• 30:13
  SPEAKER_00: And I was actually climbing around in some of these in Zion National Park many, many years ago now.
• 30:18
  SPEAKER_00: But basically that the rock is eroding off and falling down, and it's falling down and there's gaps underneath there.
• 30:25
  SPEAKER_00: And so water can rush down these things and it won't move the boulders, but it'll erode stuff along the sides and underneath of the boulders, and eventually you'll form a cave there.
• 30:34
  SPEAKER_00: If you have a bunch of boulders stacked up and a little gap underneath, and then the soil develops on top of the boulders, you can get this what are called talus caves, which can then collapse down in on themselves later on, and it can be this sort of feedback, and that can be a pseudo-karst setting as well.
• 30:49
  SPEAKER_00: Another one, Chris, is just groundwater withdrawal.
• 30:51
  SPEAKER_00: So, especially in areas where there's a limited amount of groundwater, groundwater takes up space in the earth.
• 30:57
  SPEAKER_00: And if you withdraw or pump out a bunch of groundwater, you can make a void down there, or at least it can create sort of the this sort of slumping pattern.
• 31:06
  SPEAKER_00: They're usually more associated with the small or the slow collapse sinkholes, not the really violent one, but they they are generating this pseudocarst nonetheless.
• 31:17
  SPEAKER_00: So I think let me just summarize that karst is this topographic classification where rocks under the surface are being dissolved and therefore cavities in the earth are being created, which are caves or sinkholes or disappearing streams.
• 31:31
  SPEAKER_00: Pseudocarst is creating the same phenomenon, but not with dissolved rocks.
• 31:36
  SPEAKER_00: It can create gaps in the earth in various ways.
• 31:40
  SPEAKER_00: We talked about volcanic tubes, we you know, sea cliffs can do this, we talked about talus slopes and anthropogenic factors that can create voids in the earth.
• 31:49
  SPEAKER_01: Yeah, right.
• 31:50
  SPEAKER_01: This is where my mind goes when I think of karst.
• 31:53
  SPEAKER_01: I often think of the black hills.
• 31:55
  SPEAKER_01: This ties into our earlier episode on disappearing streams.
• 31:58
  SPEAKER_00: Well, Chris, this is the beautiful thing about the Black Hills, is like anything we talk about kind of brings to mind the Black Hills because there's so much there, you know, there's so much geology there.
• 32:07
  SPEAKER_00: It's amazing.
• 32:08
  SPEAKER_01: Yes, it's a very well-kept secret, and um, I yeah, I'd love to do that.
• 32:12
  SPEAKER_01: And we're doing our best to change that.
• 32:14
  SPEAKER_01: I know I should I should stop.
• 32:16
  SPEAKER_01: The Black Hills are a horrible place.
• 32:18
  SPEAKER_01: My mind comes back to that.
• 32:20
  SPEAKER_01: Like I said, it ties into our earlier episode on disappearing streams, and the Black Hills have been in the news in the last, you know, what, three or four years because there have been a couple of major sinkholes that have opened up that are related to true karst.
• 32:35
  SPEAKER_01: These are caves that have collapsed, but the collapse has happened where neighborhoods happen to be.
• 32:42
  SPEAKER_01: And so it's actually been kind of a sad, traumatic human story where humanity and geology intersect once again, because you have you know, these people have really they lost everything.
• 32:51
  SPEAKER_01: And so it's it's made headlines.
• 32:53
  SPEAKER_01: I actually came into contact with uh some of the people that were brought in to explore these uh sinkholes.
• 33:00
  SPEAKER_01: Yeah, they're these spelunkers.
• 33:02
  SPEAKER_01: Because the Black Hills are a mecca for caves, you have a lot of uh uh spelunkers that are really, really well renowned, and uh they brought these people in to assess what's going on, one, and uh is it gonna continue and is it safe?
• 33:18
  SPEAKER_01: Okay, and um so anyway, I was I came into contact with these people because this was actually during COVID.
• 33:24
  SPEAKER_01: So I was not able to take my students into Wind Cave or Jewel Cave or anything like that, right?
• 33:30
  SPEAKER_01: Uh but these people took us into a cave that is privately owned, it's called Bethlehem, and they were one spectacular people, very, very knowledgeable about the not only the geology, but obviously caving.
• 33:45
  SPEAKER_01: Yeah.
• 33:46
  SPEAKER_01: Um, and they just really took care of us.
• 33:48
  SPEAKER_01: But the this was this grotto club was the the same group that was brought in to assess the damage that has happened in the last couple of years.
• 33:55
  SPEAKER_00: Oh, that's interesting.
• 33:56
  SPEAKER_00: I mean, it's a it's a really sort of uh sort of good point, that juxtaposition between sort of caving and um and sinkholes, right?
• 34:02
  SPEAKER_00: I mean, it's a really important thing.
• 34:04
  SPEAKER_00: Bringing up the Black Hills, when you look at this this map of the U.S., we'll put a link to the paper in the show notes.
• 34:09
  SPEAKER_00: But when you look at the sinkhole susceptibility index map of the U.S., there's some some real hot spots that stand out in the east coast of the United States, in Florida, sort of from Pennsylvania all the way down into Alabama, where the the Appalachians have exposed limestone or or dole stone type rocks that are easy to dissolve.
• 34:27
  SPEAKER_00: But the Black Hills stands out as well.
• 34:29
  SPEAKER_00: You can see the racetrack, you can see the circle, the ring of the Black Hills.
• 34:32
  SPEAKER_00: It's relatively low susceptibility on average around that, but they're there are really high points of really high susceptibility here within that area.
• 34:40
  SPEAKER_00: So, yeah, it's an interesting one.
• 34:41
  SPEAKER_00: It the Black Hills just really stands out on this map.
• 34:43
  SPEAKER_00: I thought that was kind of uh cool to see.
• 34:46
  SPEAKER_00: So it does.
• 34:47
  SPEAKER_01: That racetrack that you alluded to is you pointed to it to me when we first started talking about this, and I was amazed.
• 34:53
  SPEAKER_01: I'm like, oh my gosh.
• 34:55
  SPEAKER_01: You know, I've not seen this, I haven't seen this graphic before, and it it just uh it looks like this perfect oval around the Black Hills.
• 35:02
  SPEAKER_01: It's awesome.
• 35:02
  SPEAKER_00: It's a beautiful, a beautiful thing that traces out those those rocks there.
• 35:06
  SPEAKER_00: So I think we've done this justice, Chris.
• 35:08
  SPEAKER_00: I think we've kind of hit the the highlights and the high points, and I think I've um been fairly nice to you this episode.
• 35:13
  SPEAKER_00: So uh do you agree?
• 35:15
  SPEAKER_00: I do, I do, I do.
• 35:17
  SPEAKER_01: Actually, I was the one that was rude.
• 35:18
  SPEAKER_01: I called you a pseudo-intellectual.
• 35:20
  SPEAKER_00: So uh hey, if it's accurate, then you know it's not rude.
• 35:24
  SPEAKER_00: Hey, that's a wrap for this episode.
• 35:26
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• 35:41
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• 36:05
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• 36:06
  SPEAKER_00: Peace.