EVERYDAY SCIENCE

Detailed explanation-1: -Groundwater moves through minor cracks slowly over many years. The water dissolves the solid rock and transports it away, gradually widening the cracks and eventually forming a cave.

Detailed explanation-2: -Two types of sinkholes exist. One forms when the roof of a cave collapses and exposes the underground cavern. The second type forms when water dissolves the rock underneath soil and creates an underground chasm. Without rock to support it, the soil layer collapses and creates a hole on the surface.

Detailed explanation-3: -Most water that enters the cave comes down through the joints, which connect the cave with the surface. Where there are many joints, sinkholes can form on the surface. Sinkholes act like funnels, collecting rain water from the surface and funneling it into the cave.

Detailed explanation-4: -Caves are formed by the dissolution of limestone. Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves.

Detailed explanation-5: -Naturally occurring sinkholes form in areas where the rock can dissolve in water, which could be due to erosion or an underground stream. The nightmare scenario is catastrophic collapse, where a vast hole abruptly and without warning forms above an unsuspected cavern deep below the surface, swallowing everything above.