Jerry Black, a senior geologist at Geo Hazards, a Florida based consulting group, said sink holes are caused by a "little bit of both mother nature and human development. 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.
He explained that rainwater draining into the sinkhole carries nutrients from fertilizer and from human and animal waste. Contaminants that enter the aquifer can travel long distances rapidly—as the D.
This is news that homeowners, farmers, real-estate developers, city officials, and others are not always eager to hear, since it raises concerns about surface activities that were previously thought to be harmless, or even beneficial.
For a quarter century, Tallahassee recycled much of its treated wastewater by using it to spray-irrigate a farm southeast of the city—seemingly an ingenious instance of turning an environmental liability into an asset. But a study led by the Florida Geological Survey proved that the practice was responsible for sharply elevated nitrogen levels miles to the south, and Tallahassee has had to redesign its sewage-treatment procedure.
Even so, nitrogen levels remain a problem. The Church Sink lies near the northern edge of the Woodville Karst Plain, a four-hundred-and-fifty-square-mile section of former seafloor that extends like a terrace between the southern part of metropolitan Tallahassee and the Gulf of Mexico. The bedrock under the plain is relatively close to the surface, and it contains a number of large sinkholes, more than two dozen of which are now known to be connected by underground conduits.
The conduits are branches of the longest known underwater cave system in the United States. Since , roughly thirty miles of the system have been explored by deep-water cave divers. In , a pair of divers set a world record by making a seven-mile traverse through the system, from an opening called Turner Sink to Wakulla Springs, a state park about fifteen miles south of downtown Tallahassee.
The average depth of the traverse was close to three hundred feet—about the same as the wreck of the Lusitania—and the total submerged time was twenty-one hours. On the evening of my field trip with Arthur, I had dinner with one of the men who set the record, Casey McKinlay, and with three other divers. I asked him why he had come so far to dive in the aquifer. Nevertheless, during the past decade McKinlay and the others have come to think of themselves not just as explorers but as environmentalists.
The park used to be famous for its glass-bottomed boats, from which tourists could view multitudes of fish and easily make out mastodon bones and other prehistoric detritus more than a hundred feet below. Today, though, many of the fish are gone, and the clarity of the water has declined to the point that the glass-bottomed boats are deployed on only a handful of days.
Early the next morning, I met the divers for breakfast at their favorite Tallahassee assembly point, the Village Inn on Apalachee Parkway. Their menu choices—fried eggs, omelettes, pancakes, bacon, sausage, hash browns, toast—seemed to reflect no particular concern about the fact that they were planning to spend much of the weekend underwater.
After breakfast, we drove south, in a caravan, through heavy rain. Our destination was Turner Sink, which turned out to be a weedy, mosquito-infested mud hole in the woods. Swimming in the Floridan Aquifer is not something you simply decide to do. It included an insulated full-body undergarment and an extensive inventory of breathing tanks, each of which had been labelled, in large numerals, to indicate the maximum depth in feet for which it was intended. Non-divers think of oxygen as the life force, but it can be toxic to those who breathe it underwater in too high a concentration.
And nitrogen, which is the main component of air, is also dangerous. If divers ascend too quickly, the drop in pressure causes nitrogen dissolved in their blood and body tissues to form bubbles, and they suffer the potentially fatal malady known as decompression sickness, or the bends.
Deep-water divers prevent the bends by reducing the nitrogen in their breathing mix and by ascending very slowly, in stages. A typical two-hour dive in the aquifer, McKinlay said, requires about eight hours of submerged decompression, and the divers spend most of that time watching the clock and listening to waterproof MP3 players. Major mistakes and accidents are rare, but the consequences can be grim.
Miller apparently confused two of his tanks and, at depth, breathed a mixture intended for a hundred and fifty feet nearer the surface.
A home in Hudson, Florida destroyed by a 40 foot-wide 12m sinkhole Alamy. Sinkholes are a natural phenomenon but human activity can exacerbate the problem. Excessive pumping of groundwater, for example, can remove support from the walls of a cavity, leading to collapse. Weather is also a factor. Droughts lower the water table while heavy downpours dump tonnes of water, adding to pressure on the ceilings above cavities and often resulting in multiple collapses.
The damage was severe enough for the state division of emergency management to ask the FGS to help them prepare for similar scenarios in future. Basically, that means combining evidence for known sinkhole occurrences with geological data — depth of limestone, for example, or make-up of overlying sediment — to calculate a prediction about the relative vulnerability in a particular location.
For instance, GeoHazards Inc. A car teeters on the edge in China Rex. But the work is not cheap, often running to tens of thousands of dollars. No injuries were reported as the accident occurred in the early morning hours. Hide Caption. When the ground gives way — Eight Corvettes fell into a sinkhole that opened up beneath a section of the National Corvette Museum in Bowling Green, Kentucky, on February The sinkhole was about 40 feet wide and feet deep.
When the ground gives way — An increasing number of sinkholes have appeared in and around the neighborhood where the Lotte World Tower is being built in Seoul, South Korea. The first one was discovered in June and several others have appeared since then, according to local media reports, causing the construction of what would be Seoul's tallest building to come under scrutiny.
When the ground gives way — The rear portion of a residential home is consumed by a sinkhole November 14 in Dunedin, Florida. One resort building collapsed, and another slowly sank.
When the ground gives way — A backhoe is swallowed by a sinkhole in Montreal, Quebec, Canada, on August 6. The driver of the backhoe was not injured. When the ground gives way — A sinkhole killed a guard at a construction site in Shenzhen, China, on March The sinkhole might have been caused by heavy rains and the collapsing of old water pipes running beneath the surface, the Shenzhen Special Zone Daily reported.
When the ground gives way — Workers watch the demolition of the house where a sinkhole opened three days before in Seffner, Florida, on March 3. Sinkholes caused by acidic groundwater corroding the limestone or carbonate rock underground are common in Florida, according to the Florida Department of Environmental Protection. When the ground gives way — Buildings fell into a sinkhole near a subway construction site in Guangzhou, China, in January The hole measured about 1, square feet across and 30 feet deep and was without casualties, according to a state media report.
When the ground gives way — In July , a man inspects a foot-deep sinkhole that a family found after they heard a booming noise in their kitchen in Guatemala City, Guatemala.
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