ESC1000 Mass Wasting
what are the 4 mass wasting triggers?
1. saturation of the material with water 2. oversteepening of slopes 3. removal of anchoring vegetation 4. ground vibrations from earthquakes
what are the 6 mass wasting forms?
1. slump 2. rockslide (most dangerous) 3. debris flow/ mud flow 4. earthflow 5. creep 6. solifluction
what 3 things is each type of mass waste defined by?
1. the material involved 2. the movement of the material 3. the rate of movement
Which statement best describes slumping, a mass wasting process?
A block or blocks of unconsolidated regolith slide downhill along a curved slip surface.
Which soil horizon contains unaltered to partially-altered parent materials?
C horizon
Which mass wasting process has the slowest rate of movement?
Creep
Which of the following materials has the maximum sustainable slope angle as determined by the angle of repose?
Dry sand
Which of the following is not a factor affecting mass wasting?
Geologic age
As an erosional process, how is mass wasting different from wind, water, and ice?
Mass wasting does not require a transporting medium; gravity is its controlling force.
Which of the following statements concerning mudflows is not true?
Mudflows deposit talus slopes.
Of the following, which one would most likely be triggered by an earthquake?
Rock avalanche
Which of the following is the most rapid type of mass movement?
Rock avalanche
Which of the following mass movements is most likely to occur in a geologic setting where the rock strata are inclined?
Rockslide
Which of the following terms denotes the exposed, crescent-shaped rupture surface at the head of a slump?
Scarp
Which of the following was a major factor leading to the Gros Ventre, WY, slide?
Soils and shallow bedrock were very wet and locally saturated.
Which one of the following operate(s) primarily in areas of permafrost?
Solifluction
How do freezing, thawing, wetting, and drying contribute to soil creep?
The soil expands and contracts, lifting particles and dropping them a slight distance downslope.
Lahars are essentially mudflows associated with volcanoes and volcanism.
True
Quartz is quite resistant to weathering and is an important component of sands in riverbeds and on beaches.
True
Very fine-grained iron oxide particles account for nearly all red, yellow, and brown soil colors.
True
How do the strength and the cohesion of clay-rich regolith or soil change with the addition of water?
Water reduces the strength and the cohesion.
what material is involved in the mass wasting process?
debris, mud, earth, or rock
Features like rock ledges in badlands or rock fins standing above adjacent valleys are all examples of ________.
differential weathering
All of the following are factors affecting mass wasting except for ________.
geologic age
All of the following are factors that affect rates of weathering except for ________
geologic age of earth materials
Chemical weathering rates are highest in ________.
hot wet climates
A soil that has nearly equal amounts of clay, silt and sand is called ________.
loam
the downslope movement of rock, regolith, and soil under the direct influence of gravity
mass wasting
Which of the following mass movements is most likely to occur in a geologic setting where the rock strata are inclined?
rockslide
The word topsoil is commonly used, but not always correctly. The proper definition is ________.
the dark, organic rich layers of O and A
