Sinkholes are depressions or holes in the ground caused by the collapse of a surface layer.
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They can occur naturally or be induced by human activity. Sinkholes form when water dissolves soluble bedrock (such as limestone, gypsum, or salt) beneath the surface, creating underground voids. When these voids become too large to support the ground above, the surface collapses, resulting in a sinkhole.
Sinkholes can vary greatly in size and depth, ranging from a few feet to hundreds of feet across and deep. They are commonly found in areas where the rock below the land surface is limestone, carbonate rock, salt beds, or other rocks that can be naturally dissolved by groundwater.
Why Do Sinkholes Happen?
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Sinkholes can be triggered by both natural processes and human activities. Natural causes include the gradual dissolution of underground rock layers by acidic water, leading to the formation of voids. When these voids reach a critical size and can no longer support the weight of the soil, rock, and structures above, a sinkhole can form. In some cases, heavy rainfall, floods, or changes in the water table can accelerate this process.
Human activities, such as excessive groundwater pumping, mining, construction, and broken water or sewer pipes, can also contribute to the formation of sinkholes. These activities can disturb the underground balance, causing voids to form or existing ones to expand, leading to a sudden collapse.
Is It Normal for the Ground to Collapse?
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While sinkholes are a geological phenomenon, their sudden occurrence can be alarming and dangerous. It is not "normal" for the ground to collapse without warning, but it is a recognized risk in certain areas, especially those with soluble rock formations. Urban areas with extensive underground infrastructure are also susceptible, as aging pipes or tunnels can weaken the ground above.
Recent Incident in Kuala Lumpur
A recent and tragic example of a sinkhole occurred in Kuala Lumpur, Malaysia (23 Aug 2024), highlighting the unpredictability and danger of these events. An Indian woman was walking on a pavement in the city when, without warning, the ground beneath her feet gave way. The pavement collapsed, and she was swallowed by the sinkhole. Rescue efforts are still underway, with emergency teams working to locate and save the woman. This incident underscores the sudden and unpredictable nature of sinkholes and the importance of monitoring and maintaining urban infrastructure to prevent such occurrences.
Image: CNA/Fadza Ishak
In another incident, a large hole appeared in the same city after a drain reportedly collapsed (26 Aug 2024). While it is not yet confirmed if this was a sinkhole, the event draws attention to the potential vulnerabilities in urban infrastructure and the need for regular maintenance and monitoring to prevent such occurrences.
Sinkholes are a stark reminder of the dynamic and sometimes unstable nature of the Earth's surface. While they are a natural phenomenon or sometimes manmade, their impact can be devastating, especially in urban environments. The incident in Kuala Lumpur is a tragic example of how the ground can suddenly and unexpectedly collapse, underscoring the need for vigilance in areas prone to such events.
