The term “landslide” describes a wide variety of processes that result in the downward and outward movement of slope-forming materials including rock, soil, artificial fill, or a combination of these. The materials may move by falling, toppling, sliding, spreading, or flowing. Figure 1 shows a graphic illustration of a landslide, with the commonly accepted terminology describing its features.
The various types of landslides can be differentiated by the kinds of material involved and the mode of movement. A classification system based on these parameters is shown in figure 2. Other classification systems incorporate additional variables, such as the rate of movement and the water, air, or ice content of the landslide material.
Figure 1: An idealized slump-earth flow showing commonly used nomenclature for labeling the parts of a landslide
Figure 2: Types of landslides. Abbreviated version of Varnes’ classification of slope movements (Varnes, 1978).
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