These can occur over much more shallow
slopes than falls. The dislocated material mostly stays in contact with
the ground surface while moving.
Slides may arise due to:
- A block bounded by joints may be
pushed by forces from water in the joints, and the block then slides down
intersecting joint-planes or along a steep joint or bedding plane. This
action may begin as a slide and develop into a fall.
- Shear surfaces may form within
the soil or rock body, with slides occuring along these surfaces. The surfaces
will often be similar to a circle arc, but may have a flat bottom. The
resulting slides will be
- Mudslides sometimes take place
when there is much rainwater present to infiltrate the soil. These are
likely to occur as secondary slides, where some form of slide has already
taken place. Mudslides are described in "The Stability of Slopes"
by E. Bromhead (pg 7) as "slides of debris at a high water content."