Land subsidence

Earth fissures and subsidence can occur in former mining areas, in regions, where large quantities of drinking water are pumped from underground reservoirs or where dissolution processes in the subsurface are active. In karst areas, water-soluble stones in the bedrock are gradually dissolved by the groundwater, producing cavities. If the soil layers above them collapse, subsidence on the surface is the result, often causing serious damage to buildings or roads.

Earth scientists use various methods to investigate these processes. Based on these results, various techniques are available or under development for their investigation. One example: BGR scientists have evaluated the potential risk of the town of Staßfurt resulting from old mines nearby.

Over the last few years, satellite-supported systems have proven particularly useful as an early detection method. Movements in the bedrock often have indirect effects on the surface of the terrain. These could result in changes in the vegetation or soil moisture, which can be picked up by satellites. When examining the urban area of Bangkok (Thailand), BGR scientists used satellite data to draw up maps outlining the areal extent of the areas of subsidence in this urban area. Newest methods have been recently used for the detection of land subsidence in Semarang/Indonesia.