Define mass wasting.
The downslope movement of
sediment and rock under the direct
influence of gravity.
A __________ is formed when vertical
incision by a stream is the primary
process, with relatively minimal mass
wasting.
slot canyon
Which of the following correctly states
the role of rivers and mass wasting in
the formation of the Grand Canyon?
The Colorado River erodes downward,
then mass-wasting processes move
material from high to low areas, then
the Colorado River transports material
downstream.
Over time, mass wasting causes
__________.
canyons to widen
What rock type is the easiest for a
river to cut through?
shale
The Gros Ventre slide is evident today
by __________.
a scar, runout area, and landslide
debris filling the valley
Which of the following is a reason the
Gros Ventre rockslide took place?
Because the river eroded material at
the valley base, there was no support
of the material upslope.
A __________ acted as a sliding surface
across which material moved downhill
during the Gros Ventre Slide.
clay layer
Heavy rainfall caused the clay to
lubricate and the sandstone to
become __________.
saturated and heavy
Which of the following statements is
true regarding the aftermath of the
Gros Ventre rockslide?
The rockslide debris dammed up the
river and formed a lake.
Creep is __________.
mass wasting by the gradual downhill
movement of sediment, influenced by
freeze-thaw or wet-dry cycles
Describe how a soil particle moves
downhill during the freeze-thaw
process.
During the freeze, a soil particle
moves at a right angle away from the
surface, and thawing causes the
particle to fall back to a slightly lower
level.
Why would trees be J-shaped?
The trunks become tilted in the
downhill direction due to creep, but
continue to grow toward the sun.
Which of the following is associated
with creep?
slow and subtle movement of material
A __________ is a common result of
creep.
broken retaining wall
Permafrost is __________.
permanently frozen ground of tundra
and subarctic climates that has
remained 0°C for two years or more
__________ is an example of mass
wasting commonly seen in the active
layer above permafrost.
Solifluction
What is name of the near-surface
layer that thaws in the summer?
the active layer
If permafrost is melted, which of the
following is a consequence?
The ground subsides because the
volume of water is less than that of
ice.
What is used to keep the Trans-Alaska
pipeline from melting permafrost?
stilts
Mass wasting is possible only with the
aid of a transportation agent such as
water, wind, or ice.
False
What non-geologic term is commonly
used to describe a sudden event in
which large volumes of material move
down steep slopes?
Landslide
What is the angle of repose?
The steepest angle at which a material
remains at rest
The 2005 mass-wasting event in La
Conchita, CA, can be classified as a
______.
debris flow