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BYU GEO 110 Ch 7
Monson
30
Geography
Undergraduate 1
10/04/2012

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Cards

Term
What is mass wasting?
Definition
downslope movement of earth's materials
Term
the term landslides sometimes includes
Definition
debris flow, rock falls, and avalanches
Term
The most common landform on the erath
Definition
Slopes.
Term
Where are free face slopes more common?
Definition
On strong rocks or in arid environments.
Term
Describe a free face slope.
Definition
A high cliff of hard rock that forms a straight, nearly vertical slope segment.
Term
What is talus?
Definition
Rock fall that accumulates at the base of a cliff or slope
Term
Types of landslides
Definition
Falling
Sliding
Slumping
Flowage/flow
Creep
Term
Falling landslide
Definition
free fall of material
Term
Sliding landslide
Definition
downslope movement of a coherent block of earthmaterial along a planar slip plane
Term
Slumping landslide
Definition
Sliding along a curved slip plane producing slump blocks.
Term
Flowage or flow landslide
Definition
Downslope movement of unconsolidated material in which particles move about and mix within the mass
Term
Creep landslides
Definition
Very slow flowage. Progressively tilts telephone poles, fences and tree trunks. Trees grow faster than creep moves, so tress are crooked.
Term
Four variables in downslope movement
Definition
1- The mechanism of the movement (slide, fall, flow or complex movement) 2- Type of earth material (solid rock, soft consolidated sediment or loose material) 3- Amount of water present 4- Rate of movement
Term
Forces that influence slope stability
Definition
Driving forces
Resisting forces
Shear strength
Term
Driving forces on slopes
Definition
Move earth materials down a slope
Term
Resisting forces on slopes
Definition
Oppose the downward driving forces
Term
Shear strength on slopes
Definition
The most common resisting force. Resists by sliding or flowing along potential slip lines
Term
Slope stability is evaluated by...
Definition
calculating the Safety Factor.
Term
How to calculate safety factor
Definition
The ratio of the resisting forces to the driving forces. Greater than 1 is stable, the resisting forces exceed the driving forces. Less than 1 - slope failure can be expected b/c driving forces exceed the resisting forces.
Term
The shape of the slip surface in slides is strongly conrolled by the type of __________________.
Definition
earth material
Term
Slides have two basic patterns of movement.
Definition
Rotational, with curved slip surfaces
and
Translational, planar slip surfaces
Term
Slumps are most common in
Definition
unconsolidated earth material and in mudstone, shale and other weak rocks.
Term
Movement in translational slides
Definition
moves along inclined slip planes within and parallel to a slope.
Term
Debris flow
Definition
thick mixtures of mud, debris, and water.
Term
Angle of repose
Definition
The angle at which snow, or any loose material, is stable. Generally, stable at less than 25 degrees.
Term
Two types of snow avalanches
Definition
Loose-snow avalanches - starts at a point and widens as it moves downslope Slab avalanches - start has cohesive blocks of snow and ice that move downslope.
Term
Chutes
Definition
Tracks produced by previous avalanches that future avalanches will usually follow
Term
Three factors that will increase world-wide landslide activity.
Definition
Development in landslide prone areas
Treecutting in landslide prone areas
Changing global climate patterns will produce regional increases in precipitation
Term
Direct effects of landslides
Definition
-Injury from falling debris
-damaged homes
-blocked roads and railroads
Term
Indirect effects of landslides
Definition
-upstream flooding
-transmission of disease
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