Geoscience Reference
In-Depth Information
Rate of motion
Figure 13.16
Rates and types of
slope failure.
Extremely slow
V. slow
Slow
Moderate
Rapid
Very rapid
Extremely rapid
Rockfall
Snow avalanche
Debris avalanche
Rock slide
Debris flow
Earth flow
Debris slump
Sand run
Debris slide
Rock glide
Rock glacier
Solifluction
Creep
Velocity
slide, flow;
rate of movement
- slow, rapid;
water content
- wet, dry;
mass geometry
- sheet, block;
morphology
- scar,
lobe;
failure history
- new, reactivation.
Table 13.2
reflects
classifications in use without preferring any particular
scheme. Rates of movement are shown in
Figure 13.16
.
No single criterion unlocks the whole scheme and failure
modes are reviewed below according to whether they are
in hard rock or debris slopes.
Mode of
Rate of
Water
failure
movement
content
Type of material
Snow/ice
Rock
Rock debris
Colluvium
Soil
Flow
Very fast
Very high
Slush
o
Debris flow
q
avalanche
o
Lahar (+ volcanic debris)
q
Very fast
Low
Snow
Rock
Debris avalanche
avalanche
avalanche
Moderate-fast
High
Mudflow
Moderate
Moderate
Sand run
Very slow
Very high
Rock glacier
(Frozen)
Fall
Fast
Low
Rock fall
o
Cohesive block fall
q
o
Individual block/grain fall/topple
q
Fast
Low
Topple
o
Cohesive topple
q
Translation
Slow-fast
Low-moderate
Plane,
Block glide
oq
Grain slide
slide
wedge
slide
Rotation slide
Slow
Low-moderate
Circular slide
Debris slump
q
Soil slump
Creep/heave
Very slow
Low
Rock creep
Talus creep
oq
Solifluction
Cambering
Grain creep and rain splash
Compound translation failure
Combination of two or more, changing along a continuum of modes and
rates during movement
