slump
Less dramatic types of mass wasting move Earth materials slowly down a hillside. Slump is the sudden movement of large blocks of rock and soil down a slope. Figure below . All the material moves together in big chunks. Slumps may happen when a layer of slippery, wet clay is underneath the rock and soil on a hillside. Or they may occur when a river or road undercuts a slope. Slump leaves behind crescent-shaped scars on the hillside.