Slow and Fast Changes
Erosion keeps changing the landscape. In general destructive forces act very slowly. However, sometimes such changes happen much faster.
Sinkhole
Caves take thousand of years to form. However, after a cave has formed, the rock above it might have very little support. At some point, the rock above the cave may sink or fall into the hole made by the cave. This is called a sinkhole.
Erosion keeps changing the landscape. In general destructive forces act very slowly. However, sometimes such changes happen much faster.
Sinkhole
Caves take thousand of years to form. However, after a cave has formed, the rock above it might have very little support. At some point, the rock above the cave may sink or fall into the hole made by the cave. This is called a sinkhole.
Landslides
Landslides also happen suddenly. Erosion is one cause of landslides. Landslides are large movements of land that tumble down a steep slope. Several destructive forces help cause landslides. Erosion from rivers, rain, glaciers, or ocean water may make a slope steeper. It may also make sediments looser. If the sediments get soaked with water, they may slide. Any movement of Earth, such as an earthquake, can form cracks and shake rocks loose. This movement can start landslides.
Landslides also happen suddenly. Erosion is one cause of landslides. Landslides are large movements of land that tumble down a steep slope. Several destructive forces help cause landslides. Erosion from rivers, rain, glaciers, or ocean water may make a slope steeper. It may also make sediments looser. If the sediments get soaked with water, they may slide. Any movement of Earth, such as an earthquake, can form cracks and shake rocks loose. This movement can start landslides.