The karst
March 2, 2013 1:35 PM   Subscribe

This past Friday, the ground opened up and swallowed Jeff Bush of Seffner, Florida. He may never be found.
Sinkholes are common in the state of Florida, due to the gradual creation of caverns in the limestone that underlies the entire state. How much of a role can human development play in their formation?
posted by Countess Elena (93 comments total) 7 users marked this as a favorite

 
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posted by Pendragon at 1:37 PM on March 2, 2013


Absolutely terrifying.

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posted by jbickers at 1:40 PM on March 2, 2013


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I apologize if this seems disrespectful, but if Bush is really never rescued, I'd prefer to imagine him as the hero of a Jules Verne novel, exploring the fantastical landscapes of Hollow Earth, fighting blind cave apes, and saving Theda Bara from the assassin priests of some subterranean cult.
posted by Nomyte at 1:43 PM on March 2, 2013 [38 favorites]


That's ocean acidification for you. Grim times for the man and his family, to be sure.
posted by boo_radley at 1:45 PM on March 2, 2013


sometimes people just get sucked into holes in the fucking ground
posted by This, of course, alludes to you at 1:46 PM on March 2, 2013 [9 favorites]


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It amazes me how quickly they can just appear. We think of geology as mostly a process that requires lots of time to occur, but then sinkholes, volcanoes and earthquakes happen. They may take a while to build up steam, but when they cut loose, things happen fast.
posted by arcticseal at 1:46 PM on March 2, 2013


"Over the years the [sinkhole] costs to insurance companies have been increasing at an extraordinary rate, because the legislature prevented companies from charging rates in line with the risk," says Mr. Randazzo. "It finally reached the point where the insurance companies won the day and got the legislature to change the law, significantly weakening the sinkhole protections in the state of Florida."

Fuck you, Florida legislature.
posted by potsmokinghippieoverlord at 1:48 PM on March 2, 2013 [28 favorites]


"That part of it is very tragic," he added. "I've never heard of there being a fatality associated with these before."
That's absurd for a earth sciences professor to say. Fine, not common, but never?

Also there's no doubt that human activities exacerbate sinkhole collapses -- the biggest issue is overuse of wells that causes the water table to lower. The water no longer supports the weight of sediments and the ground can shift and sink. It's easier to deal with potential hazards in large-scale new buildings than it is for houses already there.
posted by DoubleLune at 1:49 PM on March 2, 2013 [2 favorites]


So... I moved here just in time to be swallowed up by the Earth. So that's a thing.
posted by Splunge at 1:54 PM on March 2, 2013 [4 favorites]


If a house or road sits on top of the sinkhole, it too falls into the earth, as did the Florida man who fell into a hole estimated at 20-feet-deep by 20-feet-wide.


Why can't they find him if it's only 20 feet deep?
posted by desjardins at 2:01 PM on March 2, 2013 [2 favorites]


Because of all the debris - if you google around for other sinkhole photos, you'll see how messy they can be, especially if they occur under buildings or roads. And the whole area is incredibly unstable, so they can't just dig around without risking the lives of the body recoverers.

It feels weird to be relieved to live in earthquake country instead of sinkhole country.
posted by rtha at 2:04 PM on March 2, 2013 [4 favorites]


Why aren't there any photos of this thing anywhere? Do the elder ones control the media already? What happens when they get to the websi
posted by Potomac Avenue at 2:04 PM on March 2, 2013 [4 favorites]


they were just talking about this on cbc, saying that the sinkhole is still spreading and the house next door is now in danger.
posted by mannequito at 2:05 PM on March 2, 2013


Why can't they find him if it's only 20 feet deep?

The cavern that collapsed is probably much deeper, and possibly very large. When the ground gave way it wasn't like an elevator going down; it was very chaotic, and what's on the surface of the bottom of the hole isn't generally what was on the surface when the hole opened. In particular, stuff that was at the center falls down far, then gets covered up by stuff falling as the hole widens. So he could be 40 or even 100 feet down, and the whole sinkhole environment isn't conducive to excavation to explore.
posted by localroger at 2:06 PM on March 2, 2013 [6 favorites]


When I first saw this story, it was being reported without the poor man's name and the grim assessment of his chances, so I was going to make some kind of Florida Man Fights the Mole People joke, but now that seems in poor taste to say the least. Scary to think that he was at home, in his bed when this befell him. How sad.

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posted by clockzero at 2:06 PM on March 2, 2013


Why can't they find him if it's only 20 feet deep?

Because all the crap falls on top of him, and because it's still unstable so they can't go in and dig.
posted by oneirodynia at 2:06 PM on March 2, 2013


Potomac, there's a picture on the "sinkholes are common" link. It's the still image for the NBC video clip near the bottom of the page.
posted by ceribus peribus at 2:08 PM on March 2, 2013


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posted by oneironaut at 2:08 PM on March 2, 2013


Why can't they find him if it's only 20 feet deep?

The way they work is that erosion of limestone occurs under the water table. When a sinkhole occurs, it's because the top of it (the layer of ground in between the surface and the top of the cavern) is no longer strong enough to support what's on top of it. So the possibility is not just that a house sinks down, say, 20 feet, but that everything going into that hole is basically going into an underground water-filled cavern.
posted by DoubleLune at 2:08 PM on March 2, 2013 [1 favorite]


I was really hoping to find the maps they make showing limestone and dolomite in the various states that have Karst topography. But I couldn't. You can literally find you house on the map (if you know where you live) and find out if you live in an area prone to sinkholes.
posted by DoubleLune at 2:10 PM on March 2, 2013


Huh. Up here in the Midwest, country folk use sinkholes to get rid of old appliances and cars.
posted by notsnot at 2:11 PM on March 2, 2013 [2 favorites]


Wait, I'm sorry. That's just stock footage that NBC is using in a very misleading way. I'll see if I can google up a real photo.
posted by ceribus peribus at 2:13 PM on March 2, 2013


Potomac, there's a picture on the "sinkholes are common" link. It's the still image for the NBC video clip near the bottom of the page.

Nope, thats a video of a house somewhere else.
posted by Potomac Avenue at 2:14 PM on March 2, 2013


IVE BEEN GOOGLING FOR DAYS DONT DO IT CERIBUS...
posted by Potomac Avenue at 2:14 PM on March 2, 2013 [2 favorites]


There aren't many news stories I read that immediately scare the hell out of me, but this one did. Can you imagine what was going through his mind during this? Hopefully it was quick.
posted by Brandon Blatcher at 2:15 PM on March 2, 2013 [9 favorites]


Huh. Up here in the Midwest, country folk use sinkholes to get rid of old appliances and cars.

Nice water table you got there, be a shame if something happened .. oh wait.
posted by localroger at 2:16 PM on March 2, 2013 [8 favorites]


Wait, I'm sorry. That's just stock footage that NBC is using in a very misleading way. I'll see if I can google up a real photo.

There may not be any - one of the things I read about this yesterday seemed to make it clear that the sinkhole is actually inside the house - all the photos I've seen of the house are from the front and nothing seems to be wrong, because the damage is all within the walls.
posted by rtha at 2:17 PM on March 2, 2013 [3 favorites]


Hopefully it was quick.

He was awakened from sleep by being suddenly buried alive. It doesn't get much more horrific than that.
posted by localroger at 2:18 PM on March 2, 2013 [3 favorites]


This news report video seems to be the house in question. The sinkhole can't be seen from outside.

Authorities are surprised that the house hasn't collapsed yet, so we may get pictures in a few days...
posted by ceribus peribus at 2:19 PM on March 2, 2013


The one thing I can't figure is what kind of a house, whether slab or conventional foundation, has a floor where one bedroom floor can cave in without taking the whole structure?
posted by localroger at 2:21 PM on March 2, 2013 [5 favorites]


It feels weird to be relieved to live in earthquake country instead of sinkhole country.

I guess it comes down to do you prefer to be buried and trapped above ground or below ground?

Maybe I should just move back to tornado country...that sort of death is a lot swifter.
posted by MillMan at 2:26 PM on March 2, 2013


I just saw an interview with Jeremy Bush talking about trying to pull his brother out and not being able to. The poor guy seemed absolutely devastated. He could barely speak.

There really should be some kind of media moratorium on trying to interview people who've just recently been through horrible experiences of this nature. Yes, the public wants to know about it, but show some fucking kindness and decency.
posted by TheWhiteSkull at 2:27 PM on March 2, 2013 [37 favorites]


> use sinkholes to get rid of old appliances and cars.
Also useful for getting rid of dead animals.

Human stupidity adds a special piquancy to the wellwater in karst regions.
posted by hank at 2:31 PM on March 2, 2013 [4 favorites]



IVE BEEN GOOGLING FOR DAYS DONT DO IT CERIBUS...


Well this had the predictable effect on me and I'm fresh back from Googling sink hole images. Holy shit. But yeah, I don't understand how one of these could pull the bedroom floor down without sucking the whole house in. If the foundation's not in there, then it should be holding up the bedroom floor, right?
posted by HotToddy at 2:48 PM on March 2, 2013


I can't be the only one who read it as Jeb Bush. Now that would be a story.
posted by mrgrimm at 2:51 PM on March 2, 2013 [1 favorite]


It took thousands of years for those limestone caverns to form. Which means that hole has been waiting for Jeff Bush longer than civilization has even existed.

Just think: the thing that will eventually kill you might be out there right now, silent and invisible, and you don't even know it exists. It might be a car rolling off the assembly line in a Shanghai factory. Or maybe a .44 caliber round in a box of ammunition in a warehouse in Minneapolis. Or a tiny cluster of malignant cells dividing in your pancreas. You won't know what it is until it happens, and by that time it will be too late.

You might want to go hug your kids right now.
posted by dephlogisticated at 2:58 PM on March 2, 2013 [30 favorites]


"Bury his body in the old sink hole, bury his body in the old sink hole,
bury his body in the old sink hole under cold November sky.
Then damned if I wouldn’t go to church on Sunday,
Damned if I wouldn’t go to church on Sunday,
Damned if I wouldn’t go to church on Sunday and look the preacher in the eye."

posted by BitterOldPunk at 2:58 PM on March 2, 2013 [3 favorites]


If this happened to a member of my family I would have very little patience with the onlookers staked out on lawnchairs just outside the police tape.
posted by MaritaCov at 3:06 PM on March 2, 2013 [12 favorites]


I just hope that poor guy died quickly.
posted by orme at 3:06 PM on March 2, 2013


This thread is equal parts nervous humor at the horrific and just plain abject horror.

The ground opening up and swallowing up people needs to stay in literature where it belongs.
posted by M Edward at 3:10 PM on March 2, 2013 [12 favorites]


I agree - it must have been absolutely horrifying for him. Very sad. I can't even read anymore about it because it's just way too terrifying to imagine...

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posted by foxhat10 at 3:13 PM on March 2, 2013


From what I remember of my super-special Specific Florida Ecology class, it works like this:

We have dirt-colored sand, generally, instead of... dirt. Trees grow in it, we build on it, we're adapted to this, it's not really a thing. If you were wondering why trees up and fall over sideways during heavy storms in Florida, there's your reason. Sand is rather fluid, especially when it's wet.

Under that is porous limestone. The aquifer. Think of it like a pumice stone the size of a couple of Star Destroyers. This bedrock is full of water - the aquifer is the best damn natural freshwater filtering system if I do say so myself - and as long as the rock is topped up with water, it's stable. Left on its own, it is replenished by rain and then excess leaves in the form of springs, lakes, and rivers.

In some places - like in Seffner, where this man's house is - there's a layer of thick clay between the sand and the rock. That makes things tricky.

Sinkholes are a natural part of this system. Look at a map of central Florida: those little round lakes are likely sinkhole lakes. Which can be interesting, as people dive in them and find ground sloth bones and mastodon tusks and Calusa artifacts.

We've been seeing a lot of new sinkholes forming because there's been a drought going for at least ten years now, and added to that people are slurping water out of the aquifer faster than the rain can replenish it.

Now. The sinkhole that took this man and his house could have been forming for years. Decades. Centuries, I don't know. As long as the clay layer holding up the sand and the ground (and the street, house, etc) stayed intact, it didn't matter that there was a gigantic cavern underneath. There's no good way to find these things -- or if there is, they've discontinued doing it in the name of budget cuts. But something finally gave, that night, and took that poor man with it.

(A friend of mine lives within spitting distance of this house. I want her to move, now.)
posted by cmyk at 3:15 PM on March 2, 2013 [32 favorites]


One of the weekend news shows this morning claimed he was due to move out of the house today.

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posted by tommasz at 3:21 PM on March 2, 2013 [1 favorite]


Huh. Up here in the Midwest, country folk use sinkholes to get rid of old appliances and cars.

They do in Florida, too. One of my favorite rivers in Florida runs underground for a while, reappearing occasionally in karst windows. The first sink is a mire of 70 years' worth of refrigerators etc. that people have dumped there (or dumped further upstream and which eventually ended up there).
posted by junco at 3:30 PM on March 2, 2013


The way I understood it, the real problem was when humans built drainage canals. Those caves didn't appear recently; they date back hundreds or thousands of years. The process of dissolving the limestone is a slow one.

But those caves used to be full of water and though that's not as structurally sound as soil or rock, it's better than air. That part of Florida used to be one huge river delta, and water was available in plenty to keep the caves filled.

Once the drainage canals got built, and stopped that flow of water, the caves started emptying out -- and then you started getting collapses. (There have always been collapses, of course, but they happen more often now.)

It doesn't have anything to do with acid rain or ocean acidification.
posted by Chocolate Pickle at 3:41 PM on March 2, 2013 [2 favorites]


It doesn't have anything to do with acid rain or ocean acidification.

We humans are so talented we have multiple ways of shitting our planetary nest.
posted by localroger at 3:53 PM on March 2, 2013 [2 favorites]


Acidification can make the limestone weaker, yeah. But it's not the main cause, as I understand it - the problem is we're pumping more water out of the aquifer than is being put in naturally.

But who the hell cares about making sure the ground stays put when their lawns, swimming pools, fountains, etc, are at risk?

For what it's worth, Tampa has removed damn near all the public decor that involves processed water. I miss some of those fountains, but I get the reason why.
posted by cmyk at 3:56 PM on March 2, 2013 [1 favorite]


Holy crap, that's scary. I didn't need another reason not to move to Florida, but okay.

. for Jeff.
posted by roomthreeseventeen at 3:57 PM on March 2, 2013 [2 favorites]


What a horrific way to die and I can't imagine what that poor guy's brother is going through.

The best way to think of Florida is a prehistoric sandbar. The ground is really nothing more than sand with millions of years of dead stuff mixed in. Dig more than a few feet into the ground and you hit water. Depending on where you're at it might be a little deeper but it's really right under your feet. A little deeper is the limestone and aquifer. Lots of rain and things in the ground start moving. A little drought and holes just under the surface form. You can guess what happens next.

But here's the crazy thing, if you've lived in FL for a few minutes you'll meet someone who's house is slowly falling into the ground. I can think of 3 people right off the top of my head that have had sinkhole issues. Foundations settle and sometimes sink causing huge cracks in walls and doors that won't close. Sinkhole insurance claims are damn near impossible to get paid out. A friend was offered $1 by his insurance agency to settle a sinkhole claim. No joke. It took a lawyer to get the insurance company to pony up the money to fix the house. In order to get them to cut a check he had to sign something that said he wouldn't make any further sink hole claims in the future.

It's really just one more sign that people are not meant to inhabit this state. It really is a place being reclaimed by the earth. I sometimes think about what Florida is going to look like after 100 years of climate change and it's not a pretty picture. I figure a few thousand years from now and it will be a sandbar once again.
posted by photoslob at 3:58 PM on March 2, 2013 [6 favorites]


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What a terrible way to lose a life and a loved one.
posted by Rustic Etruscan at 3:59 PM on March 2, 2013 [2 favorites]


One more tidbit and I'm done, I swear -- if you're curious about how the aquifer functions, what sinkholes and underground reservoirs and things look like, these people did some interesting video about it.

They have one video where a pair of guys with a radio receiver follow a pair of cave divers, showing where the water flows. It's fascinating stuff, they cross highways, neighborhoods, wilderness, at one point they're in a restaurant kitchen with the divers directly under them.

It's a really lovely system, until we screw it up. Then things go horribly wrong.
posted by cmyk at 4:02 PM on March 2, 2013 [14 favorites]


The 2007 Guatemala sink hole is one of those things nightmares are made of.

Or, if you're me, kind of nightmarish but exciting dreams of underground worlds.
posted by Joakim Ziegler at 4:05 PM on March 2, 2013 [3 favorites]


I could barely read the headline on this, let alone the entire story. It is quite literally a childhood nightmare.

I was born in California and at some point in my young life I either saw, read about, or overheard a story of the ground splitting open during an earthquake and swallowing up a person. It frightened me so deeply that any earthquake sent me into hysterics. My family left California before I was 6 years old (not related to my fear of earthquakes), but for years afterward, any stress dreams I had were a variation on the theme of being swallowed up by the ground.

His family heard him screaming. My brain stopped processing the story after that.

/exorcism of childhood demons.

Those aquifer videos are great cmyk, thanks.
posted by faineant at 4:14 PM on March 2, 2013


I will never complain about a New England winter ever again.
posted by sonika at 4:26 PM on March 2, 2013 [8 favorites]


this is terrible (and terrifying!) and I feel nothing but utmost sympathy for friends and family of Jeff Bush but I keep pinging hard Donnie Darko/House of Leaves imagery here. scary!!!!
posted by supermedusa at 4:36 PM on March 2, 2013


Once the drainage canals got built, and stopped that flow of water, the caves started emptying out -- and then you started getting collapses. (There have always been collapses, of course, but they happen more often now.)

It's strawberry season, and Dover is just a couple miles from Plant City, the winter strawberry capitol of America, and though it's been a mild winter, frosty nights mean emergency irrigation for growers, which taps out all the residential wells in the area, lowers the water table, and opens up sinkholes all over the area. It's an annual thing here, and eastern hillsborough county is legendary for it.
posted by toodleydoodley at 4:42 PM on March 2, 2013 [8 favorites]


I haven't been able to stop thinking about this since I read about it yesterday. (One of my first thoughts was also, "Well, maybe he's down there fighting cave creatures and discovering hidden civilizations.") The sheer horror of the earth literally opening up and swallowing someone is beyond describing.

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posted by skycrashesdown at 5:04 PM on March 2, 2013


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posted by JoeXIII007 at 5:21 PM on March 2, 2013


In Praise Of Limestone

If it form the one landscape that we, the inconstant ones,
Are consistently homesick for, this is chiefly
Because it dissolves in water. Mark these rounded slopes
With their surface fragrance of thyme and, beneath,
A secret system of caves and conduits; hear the springs
That spurt out everywhere with a chuckle,
Each filling a private pool for its fish and carving
Its own little ravine whose cliffs entertain
The butterfly and the lizard; examine this region
Of short distances and definite places:
What could be more like Mother or a fitter background
For her son, the flirtatious male who lounges
Against a rock in the sunlight, never doubting
That for all his faults he is loved; whose works are but
Extensions of his power to charm? From weathered outcrop
To hill-top temple, from appearing waters to
Conspicuous fountains, from a wild to a formal vineyard,
Are ingenious but short steps that a child's wish
To receive more attention than his brothers, whether
By pleasing or teasing, can easily take.
...
posted by thatwhichfalls at 5:37 PM on March 2, 2013 [3 favorites]


A sudden onset sinkhole is one of the plot points in the wonderful YA novel Tangerine by Edward Bloor - set in a present-day Florida in which subdivisions are taking over citrus orchards.

Thank you to everyone who shared their knowledge about Florida geology. I wonder at what point do insurance companies decide that the natural hazard risk is too great? The state of Hawaii created a special insurance program for homeowners who are building in the lava inundation zone on the Big Island. In my volcanic hazards seminar last year, one of the state volcanologists/geology professors spent about 30 minutes just raging over the idiocy of this policy.
posted by spamandkimchi at 5:47 PM on March 2, 2013 [1 favorite]


things look like, these people did some interesting

Hah, I did the graphic design and web dev for that website via an agency I work with, though I did not produce the actual content. There is some good stuff there, for sure.

posted by maxwelton at 5:51 PM on March 2, 2013


This has just horrified me in a way I didn't think anything could horrify me. I can't even fully read the article...so I have to ask, and I know this is morbid but I don't fully understand how it happens...could he still be alive? If his family heard him screaming (Jesus God that horrifies me) and tried to get him out...do they know for certain he's dead? This is just unimaginable to me.

Count me as another person who'd rather live in earthquake country.
posted by emcat8 at 5:57 PM on March 2, 2013


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posted by Elly Vortex at 5:58 PM on March 2, 2013


Wow. Years ago, my dad owned an apartment complex in Florida, a sinkhole opened up out in a field next to one of the buildings. Fortunately, it grew slowly enough for everyone to get evacuated over a week or two, but eventually the building went down the hole. Insurance paid it off, everyone broke even on the deal, with a lot of inconvenience.

But this, I never heard of a hole just opening up under a room of a house like that, and just the bedroom going down the hole. I suppose this is a Florida thing, since most houses don't have basements. Or I suppose in this case, most Florida houses as built don't have basements.
posted by charlie don't surf at 6:15 PM on March 2, 2013


I can't even fully read the article...so I have to ask, and I know this is morbid but I don't fully understand how it happens...could he still be alive?

At this point, it's extremely unlikely. As of this morning, authorities were estimating that the sinkhole had grown to nearly 60 feet deep. And it's still getting wider and deeper. With that much dirt and debris, he likely suffocated rapidly.

Poor fella. And my heart is just shattered for his family. I hope they have a good emotional support network to get them through this.
posted by MissySedai at 6:28 PM on March 2, 2013 [2 favorites]


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posted by acb at 6:35 PM on March 2, 2013


There's no good way to find these things

I was inspired by this post to go a-googlin'. They're apparently trying lots of things to image this stuff from the surface, but the techniques are resource-intensive so they're not the kind of thing you would use for blanket large-area scans.

Here's a short summary of a cool paper about an imaging technique: 2-D and 3-D Resistivity for Locating Voids Beneath Highways by Richard W. Hammack. (PDF)

They tested it on roads that have already had big sinkholes open up - in one case, swallowing a man and his car.

Scroll down in that page for a great and disturbing image showing a cross-sectional view that the scans produced of what's below the roadways... it is swiss cheese.

How much swiss cheese?

Here's the National Karst Map (PDF) so you can see how very much of this swiss cheese bedrock there is in the US.
posted by LobsterMitten at 8:36 PM on March 2, 2013 [6 favorites]


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A whole lot of that crap is in my state—same colors on the map, and nearly as much as in Florida. : (
posted by limeonaire at 8:48 PM on March 2, 2013


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House of Leaves is where my mind keeps going too, supermedusa. It's such a horrifying thing to imagine.
posted by roll truck roll at 8:49 PM on March 2, 2013


Here's the National Karst Map (PDF) so you can see how very much of this swiss cheese bedrock there is in the US.

Eh, that map is deceptive if you want to look at true Karst topography and the associated problems. To get Karst topography, you need limestone (or the other rocks they list on there that would weather similarly) and lots of rainfall. It's the combination that makes the land prone to erosion in the form of caverns and sinkholes. Without the heavy rainfall, it just won't weather the same way.
posted by DoubleLune at 8:56 PM on March 2, 2013 [1 favorite]


I will never complain about a New England winter ever again.

It kills a lot of the giant bugs and poisonous spiders and such too, sonika. I am always grateful for (if chilled by) a good killing winter.
posted by maryr at 9:33 PM on March 2, 2013 [4 favorites]


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I live in a place with the second highest number of karst features in the world (we are beaten by Slovenia, dangit.) This is not a news story I want to think about, from either the perspective of the poor man who was randomly victimized by it, or the perspective of the rescuers, who were working a heartbreaking and pretty hopeless mission in extremely dangerous conditions.

Every summer they have to do repair work on the sinkholes that keep opening up in the faculty parking lots on campus. I am going to be much, much more cautious about blithely skipping over the "construction in progress" signs now.
posted by WidgetAlley at 10:12 PM on March 2, 2013 [1 favorite]


That's ocean acidification for you.

Got proof for that VS potable water table depletion?
posted by rough ashlar at 10:26 PM on March 2, 2013


This is just horrific. Nightmare fuel.
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Just think: the thing that will eventually kill you might be out there right now, silent and invisible, and you don't even know it exists. It might be a car rolling off the assembly line in a Shanghai factory. Or maybe a .44 caliber round in a box of ammunition in a warehouse in Minneapolis. Or a tiny cluster of malignant cells dividing in your pancreas. You won't know what it is until it happens, and by that time it will be too late.

Thanks for that cheery paragraph!


"I've never heard of there being a fatality associated with these before."
That's absurd for a earth sciences professor to say. Fine, not common, but never?


Well, seems like he was just referencing his personal experience, not saying it had never happened. Maybe he doesn't use the googles? 2012 Most sinkhole deaths I found were caused by someone driving or accidentally falling into one.

Pull quote:
How often do they [sinkholes] happen?

There do not appear to be any solid numbers, but the Florida Senate Committee on Banking and Insurance reported that insurers had received 24,671 claims for sinkhole damage in that state alone between 2006 and 2010. That's an average of nearly 17 claims a day, just in Florida
.

Holy crap!!
posted by BlueHorse at 10:56 PM on March 2, 2013 [1 favorite]


The picture of the sinkhole in Guatemala terrifies me on a primal level. Like, holy mother of God what could you do to escape something like that? It's like a portal straight to Hell itself.
posted by mr_crash_davis at 11:08 PM on March 2, 2013 [3 favorites]


I stumbled over this footage of the Winter Park sinkhole of 1981 -- at ultimately 600' across one of the largest ever. Today, it's a pond.

Why can't they find him if it's only 20 feet deep?

Almost certainly that is the distance down to the top of the debris layer. There is probably no way to know, at least right away, how deep the sinkhole bottom actually goes -- think of sand through an hourglass, more or less.

The one thing I can't figure is what kind of a house, whether slab or conventional foundation, has a floor where one bedroom floor can cave in without taking the whole structure?

As I understand it, basements are uncommon in Florida (largely because of the geological conditions), and a fair number of structures are built on piers, a lot like a porch. If you have a load-bearing wall on top of a pier that gets sucked down into a sinkhole, there goes your surrounding structure.
posted by dhartung at 11:34 PM on March 2, 2013


To get Karst topography, you need limestone (or the other rocks they list on there that would weather similarly) and lots of rainfall.

In this paper with a preliminary Appalachian Karst Map from Weary, 2005 (PDF), the author reproduces a figure that might give people a guide to whether their area gets enough rain. (Fig 9, p 99) It's a US map with a rain line at 32.5" mean annual precipitation - the line starts at the pointy bit at the southern tip of Texas, comes straight north to Iowa, then turns east and straight across. So, bounding the southeastern part of the country but with slightly wider bounds of "southeastern".
posted by LobsterMitten at 11:50 PM on March 2, 2013


Better non-PDF link to that national karst map with rain line (scroll down, it's the second map shown) - and it's a more recent update on the national karst map project and various nuances of interest.
posted by LobsterMitten at 11:56 PM on March 2, 2013


I live in Florida and actually worked in Sinkhole remediation for a while before changes in the insurance agency in 2011 left me without a job. I am kicking myself for not coming into this thread sooner. Sinkholes are common, and it seems like any excuse will open one up. Drought drops the water table, and the unsupported karst collapses. Big rain during a drought? Water table rises, the water inundates the karst, and dissolves it just enough to causes a collapse. Damned if you do, damned if you don't. I have seen sinkholes open up while out drilling sites to investigate sinkholes, although rarely to this scale, I have seen ones open up that were 6-10 feet across, and they generally stabilize pretty quickly. Although they are known for having massive effects on towns. Open a sinkhole at the bottom of a lake, and suddenly the lake is gone.

One word on the insurance thing. The insurance agencies pushed the legislation through, not because they were tired of paying out for sinkholes. They were tired of paying out for bogus sinkholes. The problem that kicked off the new legislation was the housing bubble collapse. Say someone in underwater on their mortgage, and they got a sinkhole. They filed a claim, the house was declared a loss, and the insurance send you a check for your house's insured value. Voila! No more mortgage issue. You neighbor hears this, and notices a few cracks in his wall, files a claim, and thus begins a cascade effect in a neighborhood. Suddenly, there is a new get out of jail free card, and people start to exploit it. Especially when initially it is cheaper to pay out that spend the money to investigate, but it was a boom for an entire industry.

I loved the job since I was out in the field doing Geology, but it was all generally funded by the leveraging of some homeowner's misery. So getting let go was a little bit of a blessing. A lot of times the homeowners or their legal representative was out on a drill with us, and you had to be careful with what you said. My opinion was not the final say, but in any situation like this, anything you did say could be used in court. At times it was obvious that there was a sinkhole, but most times it was not all that cut and dried. There are a lot of things that can cause a house to settle poorly. Especially when almost all houses are built on reclaimed swamp. I lived in two houses that showed all the signs, but were not sinkholes.
posted by Badgermann at 6:08 AM on March 3, 2013 [11 favorites]


I was born in California and at some point in my young life I either saw, read about, or overheard a story of the ground splitting open during an earthquake and swallowing up a person.

Yes, me too. Also, mud slides. I remember a story in the 90's? when a pregnant woman asleep in her bedroom was smothered in a mudslide. After weeks of heavy rain the whole side of the house broke off, slid down the cliff side, and was buried in tons of mud.
posted by Secret Life of Gravy at 7:19 AM on March 3, 2013


They are demolishing the house now.
People gathered on lawn chairs, bundled up with blankets against unusually chilly weather. Several dozen milled about within view, including officials and reporters.

Hillsborough County Administrator Mike Merrill said officials had talked to Bush family Sunday. Crews would try their best to move the structure forward, toward the street, so the family can get some belongings, Merrill said.

"We don't know, in fact, whether it will collapse or whether it will hold up," he said.

He said crews' goal for Sunday is to knock down the house, and on Monday they will clear the debris as much as possible to allow officials and engineers to see the sinkhole in the open.
posted by Secret Life of Gravy at 7:22 AM on March 3, 2013


For a little humans shitting our planetery nest humor break, let us pause to remember that the grandmomma of all human-caused sinkholes ever was Lake Peigneur, Louisiana. And miraculously, it didn't kill anybody.
posted by localroger at 8:08 AM on March 3, 2013 [3 favorites]


I wonder if something like this could happen at Disney World?
posted by Chocolate Pickle at 10:20 AM on March 3, 2013 [1 favorite]


That would be terrible, of course, and not at all funny or darkly satisfying, not one bit.
posted by Countess Elena at 10:34 AM on March 3, 2013 [4 favorites]


Chocolate Pickle
Yes, look on google maps to the west of WDW and you will see TONS of sinkhole lakes. Rumor has it that the final straw for Horizons in Epcot was a sinkhole that opened up underneath the already shuttered attraction.

There are stories of a lot of the monorail footings and other building foundations where they dug a hole, and when they filled it, it took far more fill that what was removed.
posted by Badgermann at 11:49 AM on March 3, 2013


Chocolate Pickle, Badgermann - a similar thing happened when they were building the elevated contraflow part of the Crosstown in Tampa; they set a support column in place, put the roadway over it, and then boom. The ground couldn't handle the weight so the thing fell straight into the hole beneath. Oops. Nobody was hurt, so it wound up being funny: we can't even make highways without something going wrong.

If that massive concrete support beam and all the highway pieces hadn't been put on that piece of ground, that subterranean cavern might have continued existing for decades or centuries before caving in, probably expanding as it went. There's no way of knowing how strong the top layer is until something bursts it. Then, all you know is that it wasn't strong enough to hold whatever broke it.

One good thing that could come from Bush's death would be a renewed effort in ways to identify and stabilize sinkholes. But with Rick Scott at the helm, I should probably also wish for a unicorn and a plastic rocket, too.
posted by cmyk at 3:33 PM on March 3, 2013 [1 favorite]


For some reason, the auction scene from the Marx Brothers' "The Cocoanuts" is running through my head now.
posted by Melismata at 5:47 PM on March 3, 2013


If I were a civil engineer in Florida, I would refuse to build anything unless it was on pilings.

Deep pilings.
posted by Chocolate Pickle at 3:26 PM on March 4, 2013


A photo of the sinkhole, visible now that the rest of the house has been torn down. Article.
posted by rtha at 9:02 AM on March 15, 2013


More photos in this post.
posted by rtha at 9:08 AM on March 15, 2013


To answer my own question from upthread: It appears from the photos rtha linked that this was a slab-on-grade house. When the sinkhole opened directly beneath it the slab wasn't supported in the center, and house slabs not being designed to be cantilever bridges the slab caved in. This is why the bed and occupant were so readily swallowed, since there was no other substructure.
posted by localroger at 5:24 PM on March 15, 2013


Given the geologic circumstances I'm surprised that rebar isn't required for residential slab-on-grade, but then again this particular expression of the problem hasn't ever happened before.
posted by dhartung at 4:52 PM on March 16, 2013


After a bit of googling it appears to be fairly common for cheap-ass motherfucking contractors to omit the reinforcement in grade slabs, even when it's specified by the architect. Apparently the rationale that reinforcement isn't needed is particularly attractive where there is no freeze-thaw cycle -- which basically means I will never, ever buy a slab on grade house in Florida now.
posted by localroger at 6:42 AM on March 17, 2013


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