We will use the classification used by your textbook, which divides mass wasting processes into two broad categories and further subdivides these categories. Slope Failures - a sudden failure of the slope resulting in transport of debris down hill by sliding, rolling, falling, or slumping. Sediment Flows - material flows down hill mixed with water or air. Slope Failures Slumps - types of slides wherein downward rotation of rock or regolith occurs along a curved surface. The upper surface of each slump block remains relatively undisturbed, as do the individual blocks.
Slumps leave arcuate scars or depressions on the hill slope.
Heavy rains or earthquakes usually trigger slumps. Rock Falls and Debris Falls - Rock falls occur when a piece of rock on a steep slope becomes dislodged and falls down the slope. Debris falls are similar, except they involve a mixture of soil, regolith, and rocks. A rock fall may be a single rock, or a mass of rocks, and the falling rocks can dislodge other rocks as they collide with the cliff. At the base of most cliffs is an accumulation of fallen material termed talus .