Tornado Alley (PROG)

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Can we predict where a sinkhole might happen?

Answered by Planet Green

Discovery of a sinkhole when a sudden collapse occurs dangerous but the mere existence of an open sinkhole that appeared gradually still is highly inconvenient and expensive to fix. The moment a sinkhole collapses, anyone or anything that happens to be on the topsoil at that second is in danger. As sinkholes appear more and more often in crowded, urban areas, they represent more danger to people. In 2007, a monstrous sinkhole, which was over 330 feet (101 meters) deep, appeared almost instantly in Guatemala City, killing at least three people and swallowing the homes and buildings that had been on top of it.

Even though the actual sinkhole usually reveals itself suddenly, the erosion occurring below it can go on for years. Because sinkholes are the most dangerous at the moment they collapse, you might want to know if the land you're on is really just a thin layer of topsoil that could cave in at any moment. If you own a house, damage to its foundation could be evidence of underground erosion. Many sinkholes are caused by increased water flow, so anything that indicates unusual water activity may also be a clue. For example, if vegetation is dying unexpectedly, it could be because water is being diverted to an underground cavern, denying hydration to the local plant life. Also, muddied, polluted or new ponds can indicate that water and dirt are moving through new underground caverns and conduits. If buried signposts start slumping, that may signal that the ground below is weak.

Short of these signs, you can also watch out for the human activities that are known to contribute to sinkhole erosion. A great many sinkholes, especially those occurring in urban areas, may be due as much to human activity as to the soft bedrock and shallow overburden (topsoil) in the area. An increase in the weight the topsoil has to bear can lead to a sinkhole collapse. Drilling and construction can weaken the overburden and bedrock from below. Broken underground water pipes are especially dangerous because they can cause underground flooding and carry away the soil that surrounds the pipes, hollowing out the ground.

[ Embedded video: 200 foot sinkhole swallows 3 story building in Guatemala City ]

http://curiosity.discovery.com/question/can-predict-sinkhole-might-happen

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Fairway sinkhole swallows golfer at Waterloo course

6 hours ago • By Marlon A. Walker [e-mail]

[ Embedded ] Video: Golfer swallowed by 18-foot deep sinkhole

WATERLOO • It sure wasn’t the hole-in-one Mark Mihal had in mind.

While golfing with friends at the Annbriar Golf Course .. http://www.annbriar.com/ .. near here Friday, Mihal, 43, a mortgage broker from Creve Coeur, abruptly dropped into the ground on the fairway of the 14th hole. It was the first time a person — and not a ball — has disappeared beneath the turf in the course’s 20-year history.

It also was the first time in the memory of folks who study sinkholes in Illinois that a person has fallen into one.

“I was standing in the middle of the fairway,” Mihal said Monday. “Then, all of a sudden, before I knew it, I was underground.”

Mihal said he fell into the mud floor of an enclosure shaped like a bell, up to 18 feet deep and 10 feet wide. The rescue was precarious, he said, because no one knew whether the surface hole would grow or the enclosure would collapse.

A companion called the course’s pro shop, where general manager Russ Nobbe gathered some rope and a ladder and rushed to the rescue. Mihal had dislocated his shoulder, so Ed Magaletta, a friend and a real estate agent, climbed down and put a rope around Mihal’s waist so he could be hoisted to safety.

The rescue took less than 20 minutes, but Mihal said his mind quickly went to an incident two weeks ago in Seffner, Fla., where a sleeping man dropped into a huge sinkhole that opened beneath his bedroom. Authorities never recovered the body of that victim, Jeffrey Bush, 36.

“That certainly went through my mind when I was down there,” Mihal said. “It looked like it was more room to go down (in the hole). I wasn’t too happy to be in there.”

Mihal is very familiar with the course, northwest of Waterloo, having played it several dozen times over the past 10 years. Before Friday, he said, he was last there for a tournament just after Thanksgiving.

“It’s one of my favorite courses around,” he said. “Always in great shape, with not many houses lining the fairway, diversity in the holes.

“It’s one of the better, if not the best public course in the area.”

Nobbe, the general manager, whose family owns the course, said, “You try to think what you can do to help.” He added, “You’re trying to imagine where in the world there’s a sinkhole on 14.”

Philip Moss, a geologist who has examined the void, said sinkholes are usually visible. But in this case, Mihal said he was standing still as the ground gave way beneath him.

“This guy just really was in the wrong place at the wrong time,” Moss said.

Sinkholes are common in the St. Louis region, he said, because the bedrock here is limestone. It can dissolve in rainwater, which makes an opening he calls a “conduit.” Those large enough to accommodate people are called caves. New openings usually reveal themselves during or right after heavy rain.

“It’s a gradual process that creates a void in the soil,” Moss explained. “Over time, (the void) migrates upward through the soil to where the soil arch gets too thin to support the weight of what’s over it, and it collapses.”

Mihal, an avid golfer who owns a website called golfmanna.com .. http://golfmanna.com/ , said he can laugh now, even though the bruises remain. He said he is getting more medical tests to make sure the dislocated shoulder is the worst of his injuries.

When friends ask if he plans to golf again, he says, “Sure.”

But he’s not so sure about Annbriar, explaining, “It’d be kind of strange playing that hole again, for sure.”

Marlon A. Walker covers Illinois general news for stltoday.com and The St. Louis Post-Dispatch. Follow him on Twitter at @marlonawalker

http://www.stltoday.com/news/local/illinois/fairway-sinkhole-swallows-golfer-at-annbriar/article_1e0035d1-6ac2-59b4-ad5f-66a28c631e36.html

See also:

Could the strawberry farmers in FLA.. be a part of the problem
of these sinkholes that happen much much too often? ..

Here's two from 2010
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=85219643