Florida Sinkhole Highlights State's Geologic Instability

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."

Comments

Florida state website about it

[Trepidity]

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

Re:What's The Tech Angle?

[Frosty Piss]

What's the tech angle to this story? It's a sinkhole. Ground cover collapse is not a Slashdot story.

Oh, I don't know.. Geology? Engineering? Perhaps involving technology to detect and prevent these things?

Something like this perhaps?

Aquafilter pumping

[jacobsm]

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).

Re:Aquafilter pumping

[Grayhand]

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.

Re:Aquafilter pumping

[peragrin]

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.

Re:Pretty clever

[Anonymous Coward]

Smart of the insurance industry to make themselves useless. Now, if they never fork out, why should I have an insurance?

Because the bank requires that you pay for insurance as part of the mortgage.

Because the state requires that you pay for insurance to drive legally.

The insurances companies have been tremendously smart. Securing mandates that you pay more and more for their products, acquiring guarantees of profits, all while reducing their liability and payouts.

Tech Angle

[PPH]

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.

Re:What's The Tech Angle?

[Ol Biscuitbarrel]

Some tech input will show up regardless of what's in TFS/A. General science articles are always welcome for me at any rate. Regarding this topic, here's a good photo gallery: Notable sinkholes from around the globe.

Re:Who would have thought

[K. S. Kyosuke]

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.)

Re:Who would have thought

[Mashiki]

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.

Re:Who would have thought

[hairyfeet]

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.

Montana

[fyngyrz]

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.