EVSC 2800 Lecture Notes - Lecture 3: Mass Wasting, Earthflow, Debris Flow
18 Feb 2016
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Key terms angle of repose, consolidated material, creep, mass wasting, slump, talus, unconsolidated material. Mass wasting includes all the processes by which rock and soil move downhill under the influence of gravity. Mass wasting is part of the general erosion of the land surface. The angle of repose increases with particle size and angularity. Moist sand sticks together to maintain a steep slope. Wet sand slides and flows to a low angle. Water in some pore spaces binds particles, but water between all particles keeps them apart and allows them to flow. Various forms of mass wasting can be recognized: Rockfall newly detached blocks of rock fall freely from a cliff or mountain side. Talus accumulates at the base of the cliff. Rockslide rocks slide down a slope. Whole masses of bedrock can slide rapidly as a single unit. Movement usually occurs along downward-sloping bedding planes or joints. Creep the slow downhill movement of soil or fine-grained debris.
