A sinkhole is a hole or depression formed in soluble rock, and can occur naturally or artificially as a result of human activities. Sinkholes are found worldwide. A sinkholes can also be referred to as a cenote, swallow hole, sink, or doline. They mostly occur in Karst landscapes such as the Mamo Plateau in Papua New Guinea. Sinkholes are funnel shaped and their size depends on the area’s geology. Heavy rains and wet areas trigger formation of large sinkholes, while in dry areas, the process is slower which forms smaller sinkholes.
In recent years, sinkholes have been caused by human activities such as construction and broken sewer systems. Sinkholes can also cause catastrophes. The most recent catastrophe occurred in Guatemala in 2010, when a sinkhole 65ft wide and 100ft deep swallowed a three-story factory. Another such sinkhole exists in Xiaozhai Tiankeng, China, which is 662m deep and 626m wide. Other examples can be found in Crveno Jezero, Croatia, the Greta Blue Hole in Belize, and Sima Humboldt, Bolivia.
If the rock found underneath the land surface is soluble, the likelihood of a sinkhole occurring is high. Upon the dissolution of rock, caverns will form underground until the land surface is no longer able to support itself. When this land surface collapses, a sinkhole is formed. A sinkhole can also be formed artificially as a result of human activities such as mining. When a mine is abandoned, the land surface becomes weak and collapses to form a sinkhole. Altering natural water drainage courses can also lead to the creation of sinkholes. The weight of the material can be overwhelming, causing an existing void on the land surface to collapse.
Sinkholes provide great tourist attraction sites due to their unique appearances, especially the composition of different layers of rock and soil types. Some sinkholes are even filled with water, which make them great diving sites. One of the most beautiful and frequented sinkhole in the world is the Bimmah Sinkhole in Oman. Its emerald-tinted water attracts many tourists. The Grotto in Victoria, Australia is another famous tourist site in that region.
Sinkholes are often used as waste disposal sites which cause the pollution of ground water sources. This poses a great risk to the health of occupants in surrounding areas. Deep sinkholes are also difficult to access and those filled with water make accessibility by divers almost impossible. Some examples are the Zacaton in Mexico and the Boes Mansgat in South Africa. Sinkholes can swallow cars, homes, and roads, which threaten lives. Repairing such sinkholes cost governments and insurance companies significant amounts of money and resources. The large number of sinkholes found in the Dead Sea are also dangerous to tourists.