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Florida Sinkhole Highlights State's Geologic Instability 206

Posted by Soulskill
from the this-planet-will-not-hesitate-to-attack-you dept.
An anonymous reader writes "Last Thursday night, a sinkhole took the life of a man (TV news video, with ad) while he slept in his home in Seffner FL, near Tampa. While human fatalies are rare, sinkholes are so common in Florida that the insurance industry successfully lobbied the state lawmakers to pass legislation in 2011 making it more difficult for homeowners to claim sinkhole damages. The bedrock in Florida is limestone, a weakly soluble mineral formed from calcified deposits of sea creatures tens of millions of years ago. Above the limestone is a clay layer called the Hawthorn Formation which shields the limestone from ground water; and above the clay is sand. However, the protective clay layer is thin or nonexistent in some areas of Florida, particularly in the middle part of the state near the Gulf coast, where caves and sinkholes are common. Geologists say that human activity, particularly construction and irrigation, can trigger sinkholes by destabilizing the landscape above caverns by drawing down water tables and massing structures above them."
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Florida Sinkhole Highlights State's Geologic Instability

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  • by ArchieBunker (132337) on Saturday March 02, 2013 @03:53PM (#43055645) Homepage

    it was a great idea to start building homes on swamp land?

    • Re: (Score:3, Interesting)

      by Frosty Piss (770223) *

      ...it was a great idea to start building homes on swamp land?

      They have to build them someplace. Where would you suggest?

      • by Trepidity (597) <delirium-slashdo ... g ['kis' in gap]> on Saturday March 02, 2013 @03:56PM (#43055679)

        There's a lot of empty space in Montana I hear.

        • by alen (225700)

          What about water?

          I've read that lots of states around the Rockies have water shortages all the time

        • by cynyr (703126)

          near a super volcano, I think not!

          • by gmuslera (3436)
            Better go with a bang. If that supervolcano decides to explode life will suck in most of the world anyway.
        • Montana (Score:5, Funny)

          by fyngyrz (762201) on Saturday March 02, 2013 @08:40PM (#43057459) Homepage Journal

          There's a lot of empty space in Montana I hear.

          Wait, what? No, no empty space here. Not any. You want Texas. It's not being used for much useful other than producing oil, cattle and ignorance (not quite certain which is the state's leading export, actually.) Get some real schools in there, teach science instead of superstition, invite immigrants to help out... you'd have an actual useful state before you knew it.

          But not Montana. Please. Besides. I really don't think you'd like our -40 temps in the winter. Texas, on the other hand... perfect.

      • by PPH (736903)
        Texas.
      • by hairyfeet (841228) <[bassbeast1968] [at] [gmail.com]> on Saturday March 02, 2013 @05:51PM (#43056379) Journal

        Arkansas? Pretty countryside and the majority of it is on solid bedrock. Pretty rivers, pretty mountains, lots of pretty nature and prices are a hell of a lot cheaper than in FL which is probably why we are suddenly getting so many retirees here.

        But sometimes you just need to cut your losses which it sounds like there are parts of Florida that just aren't any good for building, same as i never understand why they keep rebuilding New Orleans, the whole reason it was put where it was was on account of river trade which isn't a big money maker anymore and its below sea level folks, time to accept that NO is a swamp and let it go, build farther up and a little higher off the ground and call that NO and be done with it. If that area of FL is so littered with sinkholes you are at risk of your house disappearing any minute time to pack up and move folks, just not a smart place to be.

      • ...it was a great idea to start building homes on swamp land?

        They have to build them someplace. Where would you suggest?

        You can build in wetlands IF you drive LOTS of friction pilings for each structure deeply enough. You might need to replace soil, even put in a raft foundation to evenly distribute the home's weight.

        "Raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor. Sometimes area covered by raft may be greater than the contact area depending on the bearing capacity of the soil underneath. The reinforcing bars runs normal to each other i

      • by cffrost (885375)

        ...it was a great idea to start building homes on swamp land?

        They have to build them someplace. Where would you suggest?

        Alaska.

      • Because the midwest is jam packed full of people.
    • by K. S. Kyosuke (729550) on Saturday March 02, 2013 @04:19PM (#43055827)

      it was a great idea to start building homes on swamp land?

      If the castle sinks, you build another one on top of it. Repeat until it stands. (Then, marry a princess with huge...tracts of land.)

      • Come on... please quote properly for full comedic effect.
        "
        When I first came here, this was all swamp.
        Everyone said I was daft to build a castle on a swamp, but I built in all the same, just to show them.
        It sank into the swamp.
        So I built a second one.
        That sank into the swamp.
        So I built a third.
        That burned down, fell over, then sank into the swamp.
        But the fourth one stayed up.
        And that's what you're going to get, Lad, the strongest castle in all of England.

      • by onepoint (301486)

        that's what they use to do in Venice, then they stopped. sinking of the land still happens.

      • If the castle sinks, you build another one on top of it. Repeat until it stands. (Then, marry a princess with huge...tracts of land.)

        Move to Minnesota. It's the most geologically stable location on the planet. There's a reason it's called the Iron Range. We have no earthquakes, hurricanes, and our buildings don't mysteriously vanish into holes in the ground. We have access to the largest reservoir of fresh water in the world as well. Global warming? Not a problem up here. Fertile farmland? Got that in spades too. Everything you need to survive just about any natural or man-made disaster is abundant here. We can survive the apocalypse. An

        • by MickLinux (579158)

          Yeah,but you have michigan next door. And chicago to the south. And you're possibly not asgeologically stable as you think. No place is perfect.

          • by Kozz (7764)

            Yeah,but you have michigan next door. And chicago to the south. And you're possibly not asgeologically stable as you think. No place is perfect.

            Michigan is next door to Minnesota? Check a map...

            • by MickLinux (579158)

              North michigan, north minnesota. Lake superior. Oh, and great lakes tectonic zone.

              PS:I was born in Wisconsin, you insensitive clods! (I really was, and I have good memories of the years I was there, at the university of Wisconsin housing for grad students with children. It was cold, and we loved it.)

        • by rgmoore (133276)

          There's a reason it's called the Iron Range.

          Yes. It's because there's lots of iron ore there. It has nothing to do with geological stability, though Minnesota is nicely stable. Of course that stability means that what passes for a mountain there is pretty laughable.

          We have no earthquakes, hurricanes, and our buildings don't mysteriously vanish into holes in the ground.

          Yes, but you do have floods, blizzards, and pestilential mosquitoes in the summer. Your winters are so miserable that people literally li

    • by Mashiki (184564) <mashiki@@@gmail...com> on Saturday March 02, 2013 @04:38PM (#43055943) Homepage

      it was a great idea to start building homes on swamp land?

      This doesn't have anything to do with swampland really, rather it has to with the limestone that makes up the base of Florida. Same with really anywhere there's limestone, Ontario, Michigan, parts of Quebec, large swaths of the NE US. Some places are more stable than others and don't have to worry about it. And there's no much you can do in some cases, and while the limestone is thick where I live several hundred feet there have been huge sink holes.

      • This doesn't have anything to do with swampland really, rather it has to with the limestone that makes up the base of Florida. Same with really anywhere there's limestone, Ontario, Michigan, parts of Quebec, large swaths of the NE US. Some places are more stable than others and don't have to worry about it. And there's no much you can do in some cases, and while the limestone is thick where I live several hundred feet there have been huge sink holes.

        Does Michigan even have much in the way of sinkholes or caves? My understanding was that glaciers in the last ice age scrubbed away most of the rock that was conducive to cave formation.

    • by adisakp (705706)

      it was a great idea to start building homes on swamp land?

      I dunno... ask the people in New Orleans who built homes on drained swampland that was below sea level that required constant pumping of water into canals (where the canal water level is higher than the hour ground levels).

      http://upload.wikimedia.org/wikipedia/commons/2/20/New_Orleans_17th_Street_Canal_filling.JPG [wikimedia.org]

    • by trout007 (975317)

      Actually the swamp land is very stable since it's always filled with water. It is the high and dry areas you have to watch out for.

    • it was a great idea to start building homes on swamp land?

      Who keeps tossing this stereotype around? The swamp land was what 1920s real estate developers sold to Yankees. These days we try to keep them as "protected wetlands". Despite the developers screaming about the goddam gubmint interfering with their rights.

      Most of Florida, actually, is built on dirty beach sand with occasional layers of clay.

      But underneath the layers of sand and clay - and the swamps - is a limestone substrate. Unlike, say granite, limestone can be eaten up relatively quickly (in geological

  • by Trepidity (597) <delirium-slashdo ... g ['kis' in gap]> on Saturday March 02, 2013 @03:55PM (#43055665)

    The state's Department of Environmental Protection has a nice collection of sinkhole resources [state.fl.us], including a database of incidents, and a poster with a map [state.fl.us].

  • Aquafilter pumping (Score:5, Interesting)

    by jacobsm (661831) on Saturday March 02, 2013 @03:58PM (#43055685)

    Let's pump massive amounts of water out of the aquafilter. What could possibility go wrong? (Living in West Central Florida on the edge of a well field).

    • Aquifer. I don't think this is connected to groundwater pumping.

      • by Grayhand (2610049) on Saturday March 02, 2013 @04:28PM (#43055891)

        Aquifer. I don't think this is connected to groundwater pumping.

        It can be the start of a sink hole. Drawing out too much water can make the aquifer collapse. It can create a void where rain water flows into washing away the collapsed parts of the aquifer creating an actual void. With broken water lines they can form in days or weeks this one could have taken years. What's scary is they used to be rare events but they are getting more common so something has changed. Just building housing developments changes the flow of water with unknown effects. Most seem to happen along coastal areas, say 20 or 30 miles of the ocean so drained aquifers and redirected water would be the likely causes. look at it this way, aquifers have been stable for thousands of years then we remove billions of gallons from them in a few decades and don't expect a problem? Think of them as big water beds. What happens to your water bed when the water drains out? Now picture it with porous rock only you stick a hose in and start intermittently flushing water in and out. When there was water in the rock it would buffer the affect of the new water but now it flushes freely through the voids washing parts away. Parts of Florida are a ticking time bomb. Personally I think the bigger problem is brackish water flooding the aquifers. The aquifers are retreating at several feet a year so eventually the fresh water will all be miles inland. All those private wells will be pumping sea water.

        • by peragrin (659227) on Saturday March 02, 2013 @05:08PM (#43056133)

          sounds like god is getting his chain saw out to cut florida out of the USA.

          It is only old folks and cubans anyways there really isn't anything to be missed there.

        • I think it's a stretch to call aquifers seriously stable over geologic time anyway, but consider the effect carbon dioxide has on the pH of water. That alone could cause a significant erosion of limestone. Keeping corals in a tank with even a slightly higher than average carbon dioxide concentration is hard because of the unpredictability of the pH, even with proper dosing of additives to keep it stable.
    • Re: (Score:2, Interesting)

      by Anonymous Coward

      This is it. Farmers are taking the water for their crops. Not to irrigate them, but to run water on the night after night to stave the frost. The net result is more and more property are sinking because the aquifers have lost most of their water.

      Farmers and the counties need to work on using reclaimed water for frost prevention, and not steal the public water table at the costs of people losing their homes.

  • Tech Angle (Score:5, Interesting)

    by PPH (736903) on Saturday March 02, 2013 @04:12PM (#43055779)

    Perhaps someone can come up with some seismic sensing technology that can detect underground voids. Similar to what the oil and gas people use, but optimized for shallower depths.

    Communities could do a periodic survey in populated areas and give property owners some advanced notice to evacuate their property. The down side is that existing property owners won't want a pre-sale seismic survey to become common practice.

    • by Solandri (704621)

      Perhaps someone can come up with some seismic sensing technology that can detect underground voids. Similar to what the oil and gas people use, but optimized for shallower depths.

      This sort of sensing usually involves setting off explosives, collecting data with seismographs placed around the area of interest, then correlating the data via tomography [wikipedia.org].

      Unfortunately, because of the explosives part, I'm pretty sure anyone trying to provide this service would eventually be sued out of existence for "causing

    • The technology for mapping subsurface voids has been around for decades, at least the 1960s, the most common method is Direct Current / Resistivity Surveying. An electric current is passed though the ground between four electrodes and the apparent resistivity (in Ohms/meter) of the subsurface is measured & mapped. Voids, filled water or clay or even empty space, have a completely different resistivity compared to the surrounding rock.

      Modern survey instruments are automated, they use dozens of computer c

  • Especially when you look at the loss of life and property caused by other natural phenomenon. If sinkholes in Florida are such a problem that we question the rationality of building homes there, then surely no one should live in Southern California where loss of life and property are several orders of magnitude higher than that caused by Florida sinkholes due to wild fires and earthquakes.

    • by Trepidity (597)

      Not to mention that, even in Florida itself, hurricanes are a much larger risk than sinkholes.

      • by matty619 (630957)

        Ya, its the 5 gallon bucket effect. A small child is much more likely to die in a 5 gallon bucket with a few inches of water in it than many of the scary local news stories like cell phone radiation and power lines. Its the things that kill few people, but can't me mitigated by individuals that freak people out.

  • Pump in sand? (Score:4, Interesting)

    by Archeopteryx (4648) * <[moc.xobop] [ta] [hcrubneb]> on Saturday March 02, 2013 @04:25PM (#43055869) Homepage

    Perhaps if you could identify where this was happening, it could be remediated by pumping in a slurry containing solids that would lock in place and resist leaching like coal ash and some kinds of sand?

    Any civil engineers care to comment on that?

    • by Chemisor (97276)

      Pump in coal ash and you can call it carbon sequestration.

      • by evanbd (210358)
        Coal ash is the solid stuff left after you burn the coal. The carbon (and heavy hydrocarbons) in coal is the stuff that burns. The stuff left behind has very, very low carbon content. The carbon basically all comes out as CO2 gas.
      • by riverat1 (1048260)

        No you can't. There isn't much carbon in coal ash. It's what's left over after they burn (nearly) all of the carbon out of coal.

    • Not a civil engineer, but the volumes required would make this a very costly solution.
      Take a look at the size of a sinkhole, even the small ones are big. Would take a shitload of trucks to fill one in.
      Can you see Florida Bob, or his insurance company, springing for this remedial work after - presumably - some type of currently nonexistent survey? Nope. Cheaper to move house.

    • Re:Pump in sand? (Score:4, Insightful)

      by evanbd (210358) on Saturday March 02, 2013 @04:46PM (#43055981)
      Given the stuff in coal ash, I don't think I want it pumped into places in contact with groundwater that people drink.
    • by hey! (33014)

      Well, the sinkhole in question is believed to be 100' across and 15' - 30' deep. That's about 4400 cubic yards of fill material, which is *not* lightweight. The material would be staged on or near unstable ground and the work would no doubt be hazardous. It'd be a complicated and dangerous engineering project; maybe if a sinkhole like this developed under Monticello, but we're talking about a couple of ramshackle ranch houses. It'd make more economic sense to put up a fence and let them fall into the grou

    • by Guppy (12314)

      Perhaps if you could identify where this was happening, it could be remediated by pumping in a slurry containing solids that would lock in place and resist leaching like coal ash and some kinds of sand?

      It's called Grouting. There was a highway improvement project back where I used to live (in Pennsylvania), involving lots of construction over porous Limestone formations. Extensive grouting was required to stablize the ground, which apparently cost quite a bit while also delaying the project.

  • "the insurance industry successfully lobbied the state lawmakers to pass legislation in 2011 making it more difficult for homeowners to claim sinkhole damages"

    Are you trying to say the insurance industry owners shouldn't be allowed to trick uneducated and become billionaires because of that? If so, say it clearer so the politicians can understand you. Some politicians are pretty thick polo players.

    • by mspohr (589790)

      The politicians are the ones who passed the laws after some friendly bribes (campaign contributions) from the insurance industry. The politicians understand the situation perfectly.

  • I feel for the friends and family of the poor guy, and wish them the best, and I'm sure it's an impractical suggestion, and in no way is it likely to happen, but In my opinion modern humans have no business living on what is essentially a giant sand bar that supports a delicate (and slowly dying) ecosystem. Though I'm admittedly biased. I simply don't like the place. The weather is almost unlivable. It's cold in the winter and unbearably hot and humid all summer. Culturally, it's not my cup of tea eith

  • by Freddybear (1805256) on Saturday March 02, 2013 @06:06PM (#43056475)

    When I lived in Miami we used to say that California might slide into the Pacific Ocean but Florida would disappear into it's own asshole.

  • Of course we've known about the state's emotional and mental instability forever. Still the only state with its own Fark tag!

    https://twitter.com/_FloridaMan [twitter.com]

    http://www.fark.com/topic/florida/ [fark.com]

  • Yeah, it figures. (Score:4, Interesting)

    by mark_reh (2015546) on Saturday March 02, 2013 @06:18PM (#43056561) Journal

    Insurance companies might have to pay some money out, so they buy the state legislature to write laws allowing them to screw the insurance purchaser.

    How long will insurance companies keep getting their way? They did the same with health care. If someone is sick they don't want to insure them because they might have to actually pay out some money. The insurance industry is more evil than cell phone and cable TV companies combined.

    We are stupid and deserve the government we elect. The human race is doomed to extinction before we figure out how to get off this rock.

  • Came here for the obligatory goatse.
  • ... this story makes me want to stay up late pouring a couple extra foundations for my house. I mean seriously: "Earth swallows man while he sleeps"?!?!? FUCK!

  • There have been scientific reports about sinkholes, reversal of water flow in aquifers (i.e. salt water working its way into former fresh sources), damage to the protected swamp areas, etc. in Florida for years now. But the only thing that put a damper on new housing developments was the mortgage securities crash. Just this year, a reasonably intelligent (!!) friend of mine - Steve D. if you happen to read this, sorry for outing you -- decided to buy a retirement spot in Fla. Steve, I'll miss you if yo

  • Much of our area is limestone, with no clay or anything on top. And it RAINS a lot.

    A few big sink holes have appeared on roads, and there are lots of cave systems.. My house doesn't even have foundations - it's built direct on the limestone.. I often wonder if the limestone is just a few feet thick, with a big cavern below.

    Still - seems our weasly insurance companies aren't as weasly as yours!

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