Sinkhole

Sinkhole

A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. It is also known as a cenote, swallow hole, or doline. Sinkholes can vary in size from 1 to 600 meters both in diameter and depth, and can be found worldwide.

Formation

Sinkholes are formed when the land surface above collapses or sinks into the cavities or when surface material is carried downward into the void. Such events are triggered by the dissolution of bedrock by circulating ground water, creating spaces and caverns underground. The most common rocks to form sinkholes are limestone, dolomite, gypsum, and salt.

Types of Sinkholes

There are three types of sinkholes: solution sinkholes, cover-subsidence sinkholes, and cover-collapse sinkholes.

Solution sinkholes occur in areas where bedrock such as limestone is exposed at the surface or is covered by thin layers of soil and permeable sand.

Cover-subsidence sinkholes are formed where the covering sediments are permeable and contain sand. Over time, small voids in the underlying limestone start to form and the sediment can be washed into these voids, leading to the formation of the sinkhole.

Cover-collapse sinkholes occur where covering sediments contain a significant amount of clay. Over time, surface drainage, erosion, and deposition of sediment transform the sinkhole into a circular pond.

Impact on Human Activity

Sinkholes can lead to significant impacts on human activities. They can cause damage to structures built on them, lead to loss of water in aquifers, and even result in loss of life. They can also impact the environment by causing changes in water quality and flow, and by creating habitats for unique ecosystems.

Prevention and Mitigation

Prevention and mitigation of sinkholes involve understanding the geology and hydrogeology of the area, proper site investigation, and design and construction practices that consider sinkhole risks. This includes the use of geophysical surveys, geotechnical investigations, and hydrogeological assessments.

See Also

• Karst topography
• Cave
• Groundwater