Sinkholes happen mainly due to the natural process of water dissolving underground rock, typically limestone or other soluble rocks like gypsum or salt. This process creates underground cavities or voids as water seeps through cracks, enlarging spaces by dissolving the rock over hundreds or thousands of years. When the surface soil or rock above these cavities loses support and collapses, a sinkhole forms on the surface. Several factors can trigger or accelerate sinkhole formation:
- Heavy rain or flooding can cause cavities to collapse.
- Human activities like leaking water pipes, construction, groundwater pumping, or draining swimming pools change water flow and support, increasing collapse risk.
- Seasonal changes, droughts, or lowering of the groundwater table remove buoyant support for underground voids, causing them to collapse.
- Concentration of water flow or heavy surface loads can destabilize the ground.
Sinkholes are common in karst terrains where soluble rocks dominate, and although natural, many sinkholes happen or accelerate due to human interference with natural water systems or land use.
