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Why Sinkholes Are Eating Florida

Sinkholes are an increasingly deadly risk in Florida, due primarily to the region's geology.

Florida is known as the Sunshine State, but living there has a dark side, as the family of Jeff Bush discovered when the 36-year-old man was killed after a sinkhole opened beneath his house last week.

Authorities are now reporting the development of a second sinkhole in Seffner, Fla., just 2 miles (3 kilometers) from the sinkhole that destroyed the Bush home, according to NBC News.

Sinkholes are an increasingly deadly risk in Florida, due primarily to the region's geology. The state is largely underlain by porous limestone, which can hold immense amounts of water in underground aquifers. As groundwater slowly flows through the limestone, it forms a landscape called karst, known for features like caves, springs and sinkholes.

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The water in aquifers also exerts pressure on the limestone and helps to stabilize the overlying surface layer, usually clay, silt and sand in Florida. Sinkholes form when that layer of surface material caves in.

The collapse can be triggered by a heavy overload, often caused by a downpour or flooding, or when water gets pumped out of the ground. When water leaves the cavities within the limestone, the pressure that supported the surface material also goes. Depending on various factors, that overlying layer can give way abruptly, as it recently did in Florida, or gradually, said Ann Tihansky, a hydrologist with the U.S. Geological Survey (USGS) in Florida. (See Amazing Photos of Sinkholes)

And Florida's groundwater has been disappearing rapidly as the state's population grows at breakneck speed: By 2015, Florida is expected to hit 20 million residents, making it the third-largest U.S. state, according to BusinessWeek.

To slake a thirsty state's population, Florida has been aggressively pumping out groundwater, destabilizing its limestone bedrock and contributing to the growing number of sinkholes, according to a USGS report.

Nowhere is this more true than in "Sinkhole Alley," the rapidly growing region of west-central Florida surrounding Tampa Bay, reports. Sinkholes can also occur naturally, but from 2006 to 2010, the number of sinkhole claims to Florida insurance companies tripled, according to BusinessWeek.

Sinkholes are even more common in Florida during the winter months. "There's a high occurrence specifically in January or February," Tihansky told LiveScience. "And that's related to freezes, when farmers pump groundwater onto crops, strawberries and oranges, to protect them from freezing."

The other peak in sinkholes in Florida occurs in May and June, which are typically dry months with the year's lowest groundwater levels, Tihansky said.

These factors, combined with unstable rainfall patterns - the Tampa Bay region has had less than one-third its usual rainfall this year, according to the Minneapolis Star-Tribune - make sinkholes an ever-increasing threat to Floridians.

LiveScience's Jeanna Bryner contributed reporting to this article.

More from LiveScience:

50 Interesting Facts About The Earth Look Out Below! 8 Amazing Sinkholes Image Gallery: One-of-a-Kind Places on Earth This article originally appeared on LiveScience. Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Police tape surrounds the house of Jeff Bush, who was consumed by a sinkhole while lying in his bed the night of March 1, 2013, in Seffner, Florida. First responders were not able to reach Bush after he disappeared.

Oct. 28, 2012 --

The Earth has the most complicated atmosphere in the solar system, so complicated that meteorologists look to other planets to understand how our weather works. Combined with its constantly active plate tectonics, our planet is truly an adventurous place to live. As the East Coast of the United States braces for a storm of historic proportions in Hurricane Sandy, we take a look back at awesome Earth events past, from earthquakes, to blizzards, to floods.

1. 1900 Galveston Hurricane This was the deadliest natural disaster ever to strike the United States. Approximately 8,000 people lost their lives on Sept. 8, 1900 in what was the biggest city in Texas at that time. Ship reports were the prevalent tool for observing hurricanes at sea, and because the wireless telegraph was in its infancy, there was precious little warning. Plus, Galveston residents had seen such storms before. Or so they thought. Many believed that they had already weathered the worst that Mother Nature could throw at them, but this hurricane brought winds above 100 mph. The storm surge knocked buildings off their foundations, leveling virtually every one in town. When it was over, 3,600 homes had been destroyed. The few buildings that withstood the enormous storm (mostly the more solidly built mansions of the wealthier residents) are maintained as tourist attractions today.

2. 2005 Hurricane Katrina Katrina was the sixth-most powerful Atlantic hurricane ever recorded, and the costliest in terms of damage. Peaking on Aug. 28, 2005, with winds hitting 175 mph, it originated in the Bahamas and was christened "Katrina" on Aug. 24. The early warnings quickly declared the potential devastation, as Katrina would weaken for short periods and then come back stronger than before. When the hurricane's sheer size became apparent, mandatory and voluntary evacuation orders were put into place and state and federal resources were targeted to minimize the impact of the coming storm. However, even today the government's response in preparation and recovery is a controversial issue. In the end, Katrina caused 53 different levee breaches in greater New Orleans, devastated the coasts of Mississippi and Alabama and did more than $80 billion in damages. Nearly 2,000 people were killed.

3. Blizzard of 1888 In the northeastern United States, March is supposed to be well past the peak time for dramatic snowfall. However, in March 1888, one of the most severe blizzards in U.S. history hit the New Jersey, New York, Connecticut and Massachusetts. Sustained 45-mph winds drove the 40 to 50 inches of snow, which fell into snowdrifts 50 feet high. Railroads were shut down, fire stations were immobilized and people were confined to their homes for up to a week. The transportation freeze from this event was partially responsible for the creation of the first underground subway system in the United States, which opened nine years later in Boston. About 400 people died from the blizzard and the cold of the week that followed -- 200 of them in New York City alone.

4. 2004 Indian Ocean Tsunami On the day after Christmas in 2004, the Sumatra-Andaman earthquake struck beneath the Indian Ocean. It was the second-strongest earthquake ever recorded on a seismograph, at a magnitude of 9.1 to 9.3, and it unleashed a killing wall of water that would claim more than 230,000 lives in 11 countries. In deep water, tsunamis travel at great speeds (300 to 600 mph) while creating small, barely noticeable waves. However, as they reach land, they slow down dramatically and those waves become enormous. On this day the waves reached as high as 100 feet, about the height of a 10-story building. Among the dead were about 9,000 tourists (mostly European) enjoying the peak holiday travel season. An estimated one-third of the dead were children.

5. 1906 San Francisco Earthquake The earthquake that hit San Francisco and parts of Northern California at just after 5 a.m. on April 18, 1906, is estimated to have been a magnitude 7.7 to 8.2. It ruptured along the San Andreas Fault, booth north and south, for about 300 miles, with the quake center located two miles offshore from the city. As a result of the quake itself, and the ensuing fires that blazed for days, the city of San Francisco was virtually leveled. At first, city and state officials announced the death toll at 376. This would have been a miraculous total had it been true. Fearing that the true figures would adversely affect real estate prices and investment in rebuilding the city, the officials had simply made up that figure. Also, hundreds of casualties in Chinatown had been ignored and unrecorded. Today the number of dead is estimated at 3,000, with 300,000 (about 70 percent of San Francisco's population) left homeless.

6. 1887 Yellow River Flood (Hwang Ho River Flood), China Flood For centuries, farmers along the Yellow River have built dikes to contain the flooding caused by silt accumulation along the riverbed. And for centuries those dikes have eventually given way to the mighty power of the rising river. In 1887, after days and days of heavy rain, the river burst through the man-made restraints and covered the low-lying surrounding areas with such speed and at such volume that most people were trapped without warning. Eventually 50,000 square miles of what had been homes, farms and villages were covered in water from the river. After the flood, millions were left homeless. The resulting pandemic and lack of basic essentials claimed as many lives as the flood itself. Total deaths are estimated to be an almost unthinkable number: between 900,000 and 2 million.

7. 1925 Great Tri-State Tornado This tornado has the dubious distinction of being the longest sustained tornado ever recorded (traveling 219 miles), as well as the deadliest (approximately 700 dead). It moved across Missouri, Illinois and Indiana and was on the ground for three and a half hours. On March 18, it touched down at around 1 p.m. just outside Ellington, Mo., and didn't dissipate until 4:30 p.m., near Petersburg, Ind. Along the way, the tornado destroyed 15,000 homes. The U.S. Weather Bureau's forecast for that day called for "rains and strong shifting winds," which one witness to the tornado later described as "a huge understatement."

8. 1934 Mount Washington Hurricane On April 12, 1934, the highest surface wind measured anywhere on Earth was clocked by the staff of the Mount Washington Observatory located in New Hampshire. The figure recorded -- 231 mph -- has become the stuff of legend. The day before seemed to indicate a typical spring storm to the three meteorologists on duty, but early the next morning that was obviously not going to be the case. By 5 a.m., winds had reached 150 mph. The readings slowly climbed until 1:21 p.m., when the 231 number was recorded. Meteorologist Sal Pagliuca wrote in the official log, "Our first thought was, will anyone believe it?" The beauty of this incredible show of nature's force? No reported injuries, no recorded property damage.

9. 1991 Halloween Storm (aka The Perfect Storm) The locals call it "the Halloween Nor'easter of 1991." In his book describing the almost unbelievable confluence of circumstances, Sebastian Junger called it "The Perfect Storm." Three separate weather events built slowly over the course of five days. First, a seemingly harmless low-pressure system formed over the Great Lakes. On its way east, it met up with an icy-cold high-pressure system from Canada. This combination formed a storm in the North Atlantic just off the coast of Nova Scotia. But it was the third, most unexpected event that made this real-life Halloween horror so historically devastating. Late-season Hurricane Grace blew up from the south to collide with the ongoing storm, and it was as if the forces of heat and cold, summer and winter, were at war. Waves 30 to 40 feet high hit the New England coast Halloween afternoon, and when it was over damages had amounted to an estimated $208 million. Twelve people were dead, six of them from the crew of the Andrea Gail, the fishing boat documented in Junger's book.

10. The Johnstown Flood On May 31, 1889, Johnstown, Penn., was a town of about 30,000 people and growing, known for the high quality of its steel production. After that day it would become synonymous with disaster. The area was (and is) prone to flooding due to its position at the confluence of the Stony Creek and Little Conemaugh River, and there is speculation that modifications made to a nearby reservoir to convert it to a luxury hunting and fishing club increased the vulnerability of the dam. The rain came to Johnstown from the west and would total as much as 10 inches in 24 hours. Creeks became rampaging rivers. By daybreak, railroad tracks and telegraph lines had been washed away. At mid-morning, the water was 10 feet high on the streets. Just after 3 p.m. the South Fork Dam burst, and for the next 40 minutes, 20 million tons of water had its way with Johnstown and the surrounding towns and villages.