Car-eating holes explained
July 14th, 2010
Car 'eaten' by sinkhole. WTSP
Look at this image carefully and you can see a car about halfway down the hole. According to newspaper reports, it’s a Toyota Camry. Sadly, there isn’t a record of what the owner said when they returned to their Toyota. I assume it was something like “Oh, s**t!”
The hole is in Tampa, Florida near the University of South Florida. When it opened up on Sunday, it ‘ate’ this car in the process. The car has now disappeared from view and the growing hole is threatening a car park and a block of flats.
This isn’t the first time Tampa residents have unexpectedly stared into the abyss. In January, a whole rash of holes (or maybe a ‘hole rash of wholes’) suddenly appeared, including a 2.5 m wide pit in someone’s back garden. Another hole near the University of South Florida burst a water pipe.
The underlying reason for Tampa’s problem is rock type combined with water use. Perhaps 1000m thick limestone and dolomite rocks lie under most of Florida. These are covered by sands and clays of various thicknesses.
Florida aquifer system (from Tihansky, 1999) and http://water.usgs.gov/ogw/ karst/kigconference/abt_karstfeatures.htm
Limestone and dolomite are mainly made of carbonates – the alkali chemicals used in some indigestion tablets for neutralising stomach acid. As with indigestion tablets, carbonate rocks react with acid water. The products of the chemical reactions are washed away. The water seeps into and widens any rocks that are full of cracks and joints, water seeps into and widens them. Over time, this process forms cavities, underground tunnels and caves.
The carbonate rock under Tampa are riddled with tunnels and cavities. Water has had many opportunities to sculpt the rocks because the sea level around the Florida Peninsula has risen and fallen many times since they were laid down beneath the sea millions of years ago.
Water also gets trapped and stored in the carbonates because they’re holey like Swiss cheese and the surrounding rocks are less permeable. It’s a bit like sandwiching a wet sponge between two glass plates. In fact, the carbonate rocks form an aquifer (a group of rocks that store water) under Florida that holds one-fifth of the water in the US Great Lakes.
Cut forward to the present day and the people of Tampa get their water by drilling into the carbonate rock aquifer and pumping it out. In winter, farmers pump lots of water from the aquifer onto their strawberries to stop them freezing.
The water filling underwater cavities and caves in the carbonates helps support the weight of the cave roof and overlying soil. When the water is pumped out, soil from above moves through cracks in the cavity roof and plugs the gap left by the water.
Sinkholes open up overnight for two main reasons (see a) and d) on the diagram below). First, water flowing downwards to fill the drained cavities eventually washes away the soil plug, causing a sudden slump of soil into the cavity and a hole to open up at the surface (figure d). Alternatively, so much water is removed that it no longer supports the cavity roof and walls. They weaken catastrophically, the cavity roof collapses and a hole opens in the ground (figure a).
Types of sinkhole (after Jennings 1985): http://www3.uakron.edu/geology/ facpages/ids/mdinsmore/
One of these explanations is likely to explain the car-’eating’ sinkhole. As an aside, all this doesn’t explain another giant ‘sinkhole’ that consumed a Guatemala clothing factory and road intersection at the end of May. From what I can gather, Guatemala City is underlain by volcanic deposits that were washed away by rain from tropical storm Agatha.
Categories: Short walks
[...] This post was mentioned on Twitter by Vivienne Raper, Vivienne Raper. Vivienne Raper said: Blogpost about car-'eating' holes – my continuing efforts to make geography simple! http://www.vivienneraper.com/blog/?p=313 [...]
……
Need cheap generic ABANA?…
……
Buywithout prescription…
.…
Buynow it…
..…
Buyit now…
..…
Buygeneric meds…
……
Buynow it…
……
Buywithout prescription…
……
Buygeneric drugs…
..…
Buygeneric drugs…
..…
Buywithout prescription…
..…
Buyno prescription…
……
Buynow…
.…
Buygeneric meds…
..…
Buygeneric pills…
.…
Buygeneric drugs…
……
Buywithout prescription…
……
Buygeneric drugs…
……
Buynow…
..…
Buydrugs without prescription…
..…
Buynow it…
.…
Buygeneric drugs…
.…
Buyno prescription…
.…
Buynow it…
.…
Buygeneric drugs…
.…
Buygeneric drugs…
.…
Buygeneric meds…
.…
Buyno prescription…
.…
Buygeneric drugs…
..…
Buygeneric pills zdg…
..…
Buygeneric drugs krg…
..…
Buygeneric meds qmo…
..…
Buygeneric drugs lzt…
..…
Buynow it tly…
……
Buywithout prescription xiu…
..…
Buynow it vhx…
……
Buygeneric meds svb…
..…
Buyno prescription wkp…
..…
Buyno prescription jui…
……
Buyit now sge…
..…
Buydrugs without prescription faj…
.…
Buyit now ojb…
..…
Buyno prescription tao…
……
Buywithout prescription ccw…
……
Buydrugs without prescription jlg…
……
Buynow it zdg…
..…
Buygeneric drugs ajd…
.…
Buygeneric drugs nih…
..…
Buydrugs without prescription ygy…
.…
Buynow it lmg…
.…
Buynow tqa…
.…
Buydrugs without prescription fva…
……
Buynow fjl…
.…
Buygeneric drugs axm…
..< /blo…
Buygeneric meds dxy…
…< /bl…
Buygeneric drugs vbr…
..…
Buyno prescription lka…
.…
Buywithout prescription…
……
Buygeneric pills…
..…
Buyit now…
……
Search rock US Charts…
warfarin zoloft…
Buy_drugs without prescription…
do cats carry ringworm…
Buy_generic meds…
stage 3 ovarian cancer…
Buy_drugs without prescription…
recent advances in cancer breast…
Buy_now…
the process of methanogens metabolism…
Buy_drugs without prescription…
soft food diet ideas…
Buy_drugs without prescription…
tuna during pregnancy…
Buy_generic meds…
ept pregnancy test…
Buy_generic meds…
market drugs edmonton…
Buy_now it…
adult circumcisions and complications…
Buy_generic meds…
adrenal cancer symptoms…
Buy_generic drugs…
gestational surrogacy…
Buy_now…
combination food diet…
Buy_drugs without prescription…
indigestion and chest pain…
Buy_now it…
buying prescription drugs in mexico…
Buy_now it…
ultimate diet pills…
Buy_generic pills…
blood pregnancy test jacksonville fl…
Buy_generic meds…
swollen ankles headache pregnancy…
Buy_generic drugs…
decongestants hypertension safe…
Buy_now it…
canine kidney failure symptoms…
Buy_generic pills…
insulin receptor inhibition…
Buy_without prescription…
questions about ortho tri cyclen…
Buy_generic drugs…
sample tlc diets…
Buy_generic drugs…
canine medi cam rx…
Buy_generic drugs…
cancer chemotherapy combination drugs…
Buy_generic meds…
rebound phenomenon during gradual clonidine withdrawal…
Buy_drugs without prescription…
kids weight gain…
Buy_generic drugs…
100 mile diet store…
Buy_generic meds…
social interaction anxiety…
Buy_without prescription…
list of anti anxiety drugs…
Buy_generic meds…
pain relief until root canal…
Buy_generic meds…
glucose to insulin ratio metabolic syndrome…
Buy_drugs without prescription…
at home diet programs…
Buy_generic pills…
interactions with azithromycin and astragalus…
Buy_it now…
how can i lower my cholesterol…
Buy_generic drugs…
dog retching vomiting weight loss…
Buy_generic drugs…
foods with triglycerides in them…
Buy_generic drugs…
space herpes…
Buy_now…
advisory group on hepatitis uk…
Buy_no prescription…
flat warts and probiotics…
Buy_generic drugs…
medicare drugs covered…
Buy_generic meds…
state of arizona ontiveros drug…
Buy_now it…
remeron dreams…
Buy_it now…
sample ncp for diabetes…
Buy_without prescription…
fruity taste and diabetes…
Buy_it now…
what year was advil introduced…
Buy_now it…
.…
Buy rock US Charts…