Encountered a "sinkhole," what to do?
A sinkhole is a hole or depression on the ground with a nearly circular shape at its mouth. It is formed when the underlying area, typically composed of gypsum, limestone, or dolomite, dissolves, causing the surface above to collapse and create a hole.
Observations before a sinkhole occurs
- Soil subsidence or sinking causes walls, fences, house pillars, and trees to rise.
- Movement or subsidence of walls, fences, house pillars, and trees causes doors and windows to become misaligned and difficult to close.
- Wilting or dullness of plants in narrow areas due to loss of moisture in the soil layer beneath the ground.
- Murky or clay-colored water in wells or ponds.
- Buildings are showing signs of settling with cracks on walls.
When encountering signs indicating a sinkhole, it's important to:
- If you hear loud noises (from the observations before a sinkhole), quickly evacuate the area. If you are in a residential area, move at least 100 meters away from that spot.
- Inform the village head, local authorities, or officials to block off the area.
- Preliminary size observation: If it appears circular/radiating, create a no-entry zone 10-15 meters away from the area. Extend the no-entry zone further from both ends if it seems elongated, as sinkhole expansion usually occurs along the length.
- Erect marked barriers around the area within a 50-meter radius.
- Avoid getting close to the area, as sinkholes can develop rapidly after initial observations, sometimes within minutes, and may enlarge within days.
Reference: General knowledge book about sinkholes Environmental Geology, Division Department of Mineral Resources.
Source: Department of Mineral Resources, Ministry of Natural Resources and Environment.