Slope movement types and processes

A fairly complete range of slope movement processes are identified and classified according to features that are also to some degree relevant to their recognition, avoidance, control, or correction. The classification includes extremely slow distributed movements of both rock and soil (designated as creep in many classifications). The classification also includes the increasingly recognized overturning or toppling failures and spreading movements. Attention is also paid to movements due to freezing and thawing. Among the attributes that have been used as criteria for identification and classification are type of movement, kind of material, rate of movement, geometry of the area of failure and the resulting deposit, age, causes, degree of disruption of the displaced mass, relation or lack of relation of slide geometry to geologic structure, degree of development, geographic location of type examples, and state of activity. A discussion of the causes of sliding slope movements considers, factors that contribute to increased shear stress and factors that contribute low or reduced shear strength.