Sinkholes

Karsts can be a big problem for homebuilders and business owners, especially in the Gulf Coast states of North America since they may form sinkholes. Sinkholes come in all sizes. Areas that are ripe for sinkholes can often be recognized by aerial or satellite photography. From these elevated views, characteristic karst circular patterns of ground cracks and depressions or lakes point to subsurface mineral dissolution. In karst regions, groundwater flow is speedy due to the high porosity and permeability of the underlying rock.

When groundwater is pumped out of these open underground water stores the water table drops, leaving a cavern. This open air space may then collapse when weighted down from above by ground construction.

The entire Florida peninsula contains solution-weathered limestone, with some cavities over 31 meters deep. Limestone in the area is covered by consolidated clays of the Miocene age and unconsolidated sands of the Pleistocene age. Groundwater is within 12 to 25 centimeters of the surface.

In 2002, the largest sinkhole in recent U.S. history opened up in Orlando, Florida, and swallowed large oak trees, park benches, and a sidewalk. Over 45 meters across with a depth of 18 meters, the sinkhole threatened nearby apartment buildings. City officials lined the sinkhole sides with plastic to keep rainfall from causing even more damage.

In Europe, geologists have discovered temperature inversions in limestone sinkholes of the eastern Alps. The Gstettner-Alm is an upland plateau area in a limestone subrange of the eastern Alps about 100 km southwest of Vienna, Austria. The Gstettner-Alm area, like many limestone areas, is characterized by sinkholes, or dolinen. The largest sinkhole in the Gstettner-Alm area, the Gruenloch, is about 1 km across. Recorded temperatures at the bottom of the Gruenloch are as low as -52.6°C, making it one of the coldest spots in central Europe. Researchers from the United States, the University of Vienna, and the Central Institute for Meteorology and Geodynamics are studying mechanisms that affect strong temperature inversions in sinkholes of different sizes near the Gstettner-Alm region.

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The Basic Survival Guide

The Basic Survival Guide

Disasters: Why No ones Really 100 Safe. This is common knowledgethat disaster is everywhere. Its in the streets, its inside your campuses, and it can even be found inside your home. The question is not whether we are safe because no one is really THAT secure anymore but whether we can do something to lessen the odds of ever becoming a victim.

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