Mass Wasting

The four processes of mass wasting are distinguished based on the nature of the movement that they produce. Flow involves the rapid downslope movement of a chaotic mass of material. Varying amounts of water may be involved. A mud flow, for example, contains a large amount of water and involves the movement of very fine-grained Earth materials. Fall involves very rapid downslope movement of Earth materials as they descend (free fall) from a cliff. Ignoring wind resistance, falling materials move at 32 ft/sec (9.8 m/sec)—the fastest rate possible in a natural system. Slides result when a mass of material moves downslope, as a fairly coherent mass, along a planar surface. Slumps are similar to slides but occur along a curved (concave-upward) surface and move somewhat more slowly.