Geologists, engineers, and other professionals often rely on unique and slightly
differing definitions of landslides. This diversity in definitions reflects the complex
nature of the many disciplines associated with studying landslide phenomena. For
our purposes, landslide is a general term used to describe the downslope movement
of soil, rock, and organic materials under the effects of gravity and also the landform
that results from such movement (please see figure 1 for an example of one type of
landslide).
Varying classifications of landslides are associated with specific mechanics
of slope failure and the properties and characteristics of failure types; these will be
discussed briefly herein.
There are a number of other phrases/terms that are used interchangeably with
the term “landslide” including mass movement, slope failure, and so on. One commonly
hears such terms applied to all types and sizes of landslides.
Regardless of the exact definition used or the type of landslide under discussion,
understanding the basic parts of a typical landslide is helpful. Figure 2 shows
the position and the most common terms used to describe the unique parts of a landslide.
These terms and other relevant words are defined in the Glossary of Landslide
Terms included in Appendix A.