Lesser-Known Sinkholes Facts That You Can 'Sink' Your Time Into

Sinkhole is a term that's common in Florida, and not in a good way. Its formation takes place because of limestone-rich bedrock.

Ranging from the heavenly pit in China, the crater in Bolivia, the Great Blue Hole in Belize, to the numerous sinkholes around the Dead Sea, this phenomenon is not unheard of across the world.

Apart from catastrophic sinkholes, there is not much harm to life with the normal and gradual occurring ones.

Meaning Of Sinkholes

Sinkholes are usually naturally occurring depressions or holes on the Earth's surface.

The dissolution of carbonate rocks, which may be gradual or sudden, create these depressions on the ground. Sinkholes could vary in size and depth. Water seeping through bedrocks prone to dissolution, is the primary cause of sinkholes.

Florida is one of the main places where most of the naturally-formed as well as human activity-caused sinkholes can be found.

While there are other states in the US, such as Missouri, Texas, and more, to name a few, where the state of the bedrock and soil is suitable for sinkhole formation, this problem isn't really specific to the US; rather, it happens all over the globe.

Formation Of Sinkholes

The rapid, chemical disintegration of a bedrock made of carbonate rocks like limestone, dolomite rock, or evaporite rocks like gypsum or rock salt, causes sinkholes.

While there are natural sinkholes and manmade sinkholes, the three distinct types are solution, cover collapse, and cover subsidence.

The degradation of a carbonate-rock bedrock by continual water erosion causes solution sinkholes (karst). Often, large sinkholes that appear abruptly are cover collapse sinkholes, resulting from the surface rock-layer collapsing under its weight due to erosion of the supporting bedrock and soil below.

On the other hand, cover subsidence sinkholes are slow-growing and are characterized by a depressed surface with rain water accumulation, with clay and sand settling into cracks and holes.

Technically, rainfall seeping through the soil on the land surface, mixes with carbon dioxide, resulting in mildly acidic water in its reaction with decaying vegetation. This dissolves the limestone gradually and leads to pores and cracks, eventually leading to sinkholes.

Additionally, drought accompanied by severe withdrawal of groundwater causes sinkholes. Droughts, followed by heavy rains, are yet another reason for sinkholes, by causing pressure on the ground.

Incidentally, in Florida, the limestone is nearer to the water surface, which can cause erosion. This accelerates the creation of a sinkhole. It isn't uncommon for people with homes in Florida to experience cracking and erosion of soil.

How Sinkholes Affect Humans And Animals

It is evident that sinkholes are capable of swallowing large portions of land, including anything on it like roads, buildings, humans, or animals.

Ironically, the impact on humans is caused by human activities as well. Mining, construction activities, drilling wells, creating artificial ponds, and even heavy traffic could lead to sinkholes.

Especially in urban and suburban places, sinkholes can be catastrophic with the destruction of highways and buildings. The quality of water is also affected at times due to sinkholes. The collapse of the earth's surface causes the surface water to seep into the underground drinking water source.

Apart from sinkholes being able to damage the foundation of buildings, toxic chemicals underneath the earth's surface may rise and pollute groundwater.

Prevention Of Sinkholes

While naturally occurring sinkholes can't be prevented, the ones caused by human activity could be avoided to a great extent.

Regular maintenance of underground systems, as well as plumbing, might avoid sinkhole damage in the middle of the city. Also, maintaining high water tables, practicing water conservation, along with drought restrictions will help prevent sinkhole occurrences.

FAQs

How deep can sinkholes get?

While sinkholes can range from a few feet deep to a depth of 2,000 ft (609 m), the deepest known sinkhole is the Xiaozhai Tiankeng in China, which is about 2,171 ft (662 m) deep and 2,054 ft (626 m) wide. Another sinkhole - Crveno Jezero in Croatia, is 1,738 ft (530 m) deep and has nearly vertical walls.

How can sinkholes be prevented?

If you're able to catch the early warning signs of a sinkhole, the hole could be injected with grout to rebuild the foundation of the deteriorating bedrock. This is similar to a dentist filling a cavity.

Has anyone fallen into a sinkhole?

While people falling into sinkholes is a very rare event, in 2013, a man from Tampa fell into a sinkhole that opened under his house, while he was sleeping.

What are the first signs of a sinkhole?

Unexplainable cracks appearing in your home's foundation, walls and floors, leaning trees, doors and windows not closing properly, and cavities appearing in your yard or garden are some of the initial signs of a sinkhole. However, not all homes that show signs of sinkhole damage are really damaged by sinkhole activity.

How will you survive from a sinkhole?

If you've had a fall in a sinkhole during its formation, the safest way to survive it is the parachute landing fall, by covering your head, tucking your knees while keeping your legs together, and falling on your side and rolling backward.

Where does a sinkhole end?

Commonly, a sinkhole is known to be funnel-shaped with a wide opening on the surface of the ground, narrowing towards the bottom. The debris of the surface, together with the limestone (or other materials prone to disintegration) bedrock sediments at the bottom of the sinkhole.

Do sinkholes grow?

A sinkhole can keep growing for years or decades. This depends on how long the ground above the hole supports the weight of the sediments on it.