Journal of Geology & Geophysics
Open Access

An Overview on Naturally Occurred Sinkhole

Rajiv Jain^{* *}Correspondence: Rajiv Jain, Department of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India, Email:

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Description

A hole that forms in the ground when flowing water dissolves surface rock is called sinkhole. Generally this surface rock is limestone, by the movement of water this limestone is eroded or worn away. In a landscape limestone is presented underneath the soil, and limestone has some cracks, these cracks are called joints. When the water from rainfall collected into the cracks of the limestone, slowly the limestone dissolves and carried away. The limestone joints widen until the ground becomes unstable and collapse. The collapse often happens very suddenly and without any warnings. The water collected from rainfall forming sinkholes. In recent times on February 11th a sinkhole is naturally formed on the Bringi nullah at Wandevalgam in Kokernag area of the south Kashmir district in Jammu and Kashmir. This is disturbed entire flow of stream. Technical teams of Department of Earth Sciences, Geology and Mining, visited and conducted technical tests to find out the consequences behind the event. The technical test conducted is Proton Precession Magnetometer (PPM) and concluded that it is naturally occurred geological event.

At the area of sinkhole, limestone presented is a soluble type of limestone and belongs to Triassic limestone. The dissolutions of the limestone over a long period of time create cavities in the rock and these cavities may cave gradually or suddenly. The results of PPM test carried out that underlying cavern is 100 meters long downstream and from emergence, water is continuously flowing into the sinkhole; there is a possibility of a large network of water holding reservoir or underground cavity in that downstream. The area has wide range of carbonate milts distribution. The dissolution of these carbonate milts can create various karstic features like sinkholes, swallow holes, conduits, caves, shafts, etc. and the same is no cause of panic and worry. Sinkholes also form when cave roofs collapse. Sinkholes often are in the shape of funnel-shaped, wide end open at the surface and narrow end at the bottom of the pool. Sinkholes are varying from shallow holes with the difference of 1 meter depth; pits have more than 50 meters depth. Water can drain through a sinkhole into a cave or an underground channel. When the mud or waste plugs these caves then it fills with water and become a pond or lake. Especially where the areas have abundant rainfall and rock beneath the soil surface is limestone then those areas have naturally occurred sinkholes. When the roof of an underground cave collapse, then it will expose water to the surface above the sinkhole, these types of sinkholes are called Cenote sinkholes. There are more than 2000 Cenote sinkholes are located in the Yucatan Peninsula of Mexico, those are the main source of fresh water for people in that area. If the sinkhole is developed at the sea bank or at the Iceland then it is called as blue hole or marine cavern. A sinkhole is at very depressive to the ground then it is called crown hole. Qattara Depression is the world’s largest sinkhole located in western Egypt desert area with 436 feet deep and 84 miles wide.