Chapter 3 : Mass wasting
Factors influencing mass wasting (5)
1. Strength of slope and cohesion compostion 2. Gradient (slope) 3. Water presence 4. Tectonic activity : earthquakes/volcanoes 5. weathering, climate, vegetation, biological activity
Three external processes:
1. weathering 2. erosion 3. mass wasting
Rock falls result in what?
A Talus Slope
(Definition) CREEP
Almost imperceptable down slope movement of materials
Where do external earth processes occur?
At or near earth's surface and are powered by sun's energy
This type of movement commonly occurs even on very gentle slopes
Creep
What form of mass wasting does the most long-term economic damage?
Creep
What is the slowest mass movement?
Creep.
Mass Wasting
Downslope movement of earth's materials due to gravity
A rock avalanche is a type of this mass movement
Fall
Material falls through air, typically on very steep slopes
Fall
4 examples of mass movements
Falls, slide, flow, creep
"The earth's surface is never perfectly ____ but instead consists of ___."
Flat, Slopes
A lahar is a type of this mass movement
Flow
Material involved in this type of mass movement is saturated with water
Flow
What is the controlling factor in mass wasting?
Gravity
How is mass wasting classified?
How quickly material moves, what its composition is, and mannar of movement
Definition of FALL
Movement of material in air
(Definition) SOLIFLUCTION
Only occurs in areas of permafrost. Slow, downslope flow of water-saturated soil
Vegetation
Plant's root systems stabalize by binding soil
A slump is this type of movement
Slide
Layers of clay below the surface often are the cause of this type of mass movement
Slide
Material moves along surface in type of mass movement
Slide
What can trigger mass wasting events?
Tectonic plates, gravity, excessive water
(Definition) Erosion
The physical removal of material by a mobile agent ie flowing water, waves, wind, ice
Angle of Response
The steepest angle at which material remains stable. 25-40 degrees
(Definition) mass wasting
Transfer of rock and soil downslope under influence of gravity
Definition of FLOW
Viscous fluid and hapens during warming tempuratures
From where does the energy that powers internal processes come?
earth's interior
Definition of SLIDE
material is cohesive but slides down plain or surface(sediment layers, faults, joints) A type of mass movement
Definition of weathering
physical breakdown (disintegration) and chemical alteration (decomposition) of rock at or near earth's surface
Examples of FALL
rock fall, avalanche
Examples of SLIDE
slump (curved surface)
From where does the energy that powers external processes come?
sun
A few examples of internal processes
volcanic activity, earthquakes, mtn building
