Unit 7 Day 4
Mass Movements
Objective
3. Describe the agents of erosion:
Variables that influence Mass
Movements
,
(running water and waves),
, and
.
4. Explain the erosional and depositional results of
gravity due to down-slope movement and mass
movement (landslides, mudflows, and avalanches).
Mass Movements
Earth’s surface is constantly changing.
breaks down materials and
prepares them for erosion and deposition.
Mass movements are the
movement of
loose sediments and rock as a result of
The weight of the material works to pull the material
down a slope as a result of
The materials resistance to sliding or flowing affects
mass movement as a result of
Triggers such as
can shake
materials loose from a slope
The earth materials that are moved range from
to
Erosion
the soil at the foot of a
slope increases the potential of earth materials to move

is a major variable even if it is not
working as a transport agent
Mass movements range from extremely
motions to
, falls, and flows
–Too little water allows the sediment grains to
and increase the potential for movement
–Too much water will
the materials and
increase the weight to make the slope unstable
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Types of Mass Movements

is the slow, steady downhill
movement of loose, weathered materials
–Soils are especially susceptible to creep

is mass movements where the
materials move as if they were a

are swiftly moving mixtures of .
and can be triggered by
earthquakes or volcanic vibrations.

is the rapid, down slope movement
when a
block of loose
soil, rock and debris separates from the underlying
bedrock

are common on
slopes
where weathered bedrock gets fully saturated by water

are landslides that occur in
mountainous areas with thick accumulations of

occur when the material breaks contact
with the ground and falls

occur when a sheet of rock
moves downhill on a sliding surface

occur when the mass of material in a
landslide
and slides along a
Slumps are common along highways and after rains
that reduce the frictional contact between grains and
acts as a
between the
surface and underlying layers

are common to areas at
high elevations and in steep road cuts and on rocky
shorelines
Homework
Read Ch 8
Remember you can choose
Applying Main Ideas
and Thinking Critically Questions for
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