Monday, August 26, 2013

Port Discover: A look at sinkholes from geology to mythology

By: Judi Stuart
Port Discover: Visitor Services Manager
Port Discover: A look at sinkholes from geology to mythology
Recently, Summer Bay Resort in Clermont, Fla. visitors thought they were hearing an impending thunderstorm, but within a few hours, one-half of the resort had collapsed into a 100-foot hole in the earth. One hundred, five guests quickly evacuated, and miraculously no one was injured.

During last March, sixty miles southwest of the resort a man sleeping in his bed was swallowed-up by a sinkhole, and he was never seen again. Geological testing done fifteen years previously in the area of the resort had shown that the ground was stable. Twenty percent of the U.S. is prone to having sinkholes including Florida, Alabama, Missouri, Kentucky, Texas, Tennessee, and Pennsylvania.

North Carolina has some areas in the piedmont and the southern coast that have the conditions necessary for sinkholes to form. Northern coastal areas are not at risk for developing sinkholes.

Last year, an eight-foot wide sinkhole swallowed a car in Durham. A twenty-foot wide sinkhole was caused by a waterline break that weakened the earth below. Since 2010, Raleigh has experienced a sinkhole that took down a city bus and a few months later a sinkhole opened on Wade Ave.

Geologists know that sinkholes appear in karst terrain where the underlying rock of gypsum, limestone, or other carbonate rock can be dissolved by underground water. When the rock becomes unstable because of the water flow, the ground above collapses into the hole that has been formed. Often the event happens quickly and with no warning.

Sinkholes can be a few feet or hundreds of acres wide and the depth can range from one to one hundred feet. They have swallowed highways, buildings, and swimming pools. The more urban the setting, the more damage is done.

Human activities that can eventually contribute to the earth’s giving-way include broken pipes, old landfills and collapsed mines. Scientists working at the U.S. Geological Survey (USGS) develop geological maps which are used by planners, policy makers, and the public to determine if land is at risk.

For thousands of years, Mayans have inhabited the Yucatan Peninsula, and the ancient Mayans were advanced in mathematics, language, and art. The peninsula itself, which is surrounded by the Bay of Campeche, the Gulf of Mexico, and the Caribbean Sea is underlined with limestone that makes it vulnerable to the formation of sinkholes.

Ancient Mayans considered the geological phenomenon to be a gateway to the underworld and the home of their god of water, Chac.

These deep wells or cenotes were considered sacred places, and often the Mayans would throw the human victims of their sacrificial ceremonies into the clear water.

In modern times, the wells have been explored and human remains and jewelry have been found. Mayans thought that they gained favor with their gods by performing sacrifices.

Even now, some people consider it a blessing to be able to drink from the cenotes.

Often in human history science, religion, and mythology form a continuum of human understanding.

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