Inside the Science of Sinkholes - East Idaho News
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Inside the Science of Sinkholes

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GETTY 111114 Sinkhole?  SQUARESPACE CACHEVERSION=1415734371301iStock/Thinkstock(NEW YORK) — Another day, another sinkhole. The latest one to develop is in Florida.

A family had minutes to escape before what appeared to be a sinkhole swallowed up a car and driveway.

Other harrowing images of sinkholes have emerged this year — including several cars that were engulfed at the National Corvette Museum in Kentucky and others as far away as Crimea and Siberia.

Jerry Black, a senior geologist at Geo Hazards, a Florida-based consulting group, said sinkholes are caused by a “little bit of both mother nature and human development.”

Here are four answers to some of the most common questions about the science of sinkholes:

How does a sinkhole form?

A sinkhole is most common when the bedrock is limestone, carbonate rock, salt beds or other rocks that can be dissolved by water, according to the United States Geological Survey.

As the groundwater dissolves the carbonate bedrock, gaps form beneath the surface. Sinkholes happen when the spaces below the ground get too wide, causing the land to collapse into the earth — eating roads, homes, cars and anything else in its way.

Sinkholes can be anywhere from one to 100 feet deep, according to the USGS.

Why are there so many sinkholes in Florida?

Florida sits on several thousand feet of limestone, which, coupled with its extensive groundwater system and the strain put on it from a growing population, creates the perfect storm to cause numerous sinkholes every year.

Other states that are also especially susceptible to sinkholes are Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania, Black said.

How can I tell if a sinkhole is developing?

Most sinkholes are isolated events and form gradually over time. Black said the “sensationalistic” sinkholes that have swallowed homes and even killed one Florida resident, are incredibly rare.

“You can see subtle depressions at the surface,” he said. “For the ones that happen overnight there is not that much time or any kind of warning before they happen.”

Can humans cause sinkholes?

Yes. Anytime when natural water drainage patterns are changed, it’s feasible sinkholes can develop.

“Here in Florida, our groundwater is our major source of water for all municipalities,” Black said. “There has been times that over-pumping and drawing down the water table has created sinkholes.”


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