What is sinkholes.

Sinkhole is a cavity in the ground , especially in a limestone formation, caused by  water erosion and providing a route of surface water to disappear underground . A sinkhole is also known as a cenote, swallow hole or doline, is a depression or hole in the ground caused by the some form of collapse of surface layer. This also may cause sinkholes.

Types of sinkholes.

Majorly, there are three types of sinkholes .There are dissolution sinkholes, cover subsidence sinkholes, cover collapse sinkholes.

Dissolution sinkholes.

This sinkholes are the result of there not being much undercover, like vegetation, over the bedrock. Water slips through pre-existing holes in the bedrock and brings to circulate through the bedrock. Water from rain and runoff slowly trickles through crevices in the bedrock, dissolving it. As a result the depression forms. Dissolution sinkholes happen slowly and are generally not dangerous, but one that becomes a pond can drain suddenly if water makes it through the protective bottom layer.

Cover subsidence sinkholes.

Occur where the cover material is relatively incohesive and preamble, and individual grains and sand move downward in sequence to replace grains that have already move downward to replace dissolved limestone. Dissolution and infilling continue, forming a noticeable depression in the land surface. In areas where cover material is thicker, or sediments contain more clay, cover- subsidence sinkholes are relatively uncommon, are smaller, and may go undetected for long periods.

Cover collapse sinkholes.

Cover – collapse sinkholes may develop abruptly (over a period of hours) and thus cause catastrophic damages. They occur where the covering sediments contain a significant amount of clay. They are smaller and thus may go undetected for long periods. Over time, surface drainage, erosion, and deposition of sediment transform the steep-walled sinkhole into a shallower bowl-shaped depression. The cavity eventually breaches the ground surface, creating sudden and dramatic sinkholes.

Some dangerous sinkholes.

1. Qattara Depression.
2. Berezniki.
3. Guatemala City.
4. Sarisarinama.
5. Bimmah.
6. Mount Gambier.
7. Unidentified Unfortunate House.

https://wordpress.com/refer-a-friend/3Yq7E4ZIorrQgYn44PeM/