Mass Wasting Flashcards
downslope movement of rock, regolith, and soil under the direct influence of gravity
Mass wasting
does not require a transporting medium such as water, wind, or glacial ice
Mass wasting
filling of pores: destroys cohesion
oversaturation: reduces internal resistance
additional weight
Water
moves unconsolidated granular materials
produces unstable slopes
Over-steepened slope
caused by nature and human activities
Over-steepened slope
angle at which material remains stable
Angle of repose
slope angle less than the angle of repose
Slope remains stable
slope angle grater than the angle of repose
Mass wasting will occur
root system bind soil and regolith together
shields soil surface from erosion due to rain
Vegetation
dislodge enormous volumes of rock and unconsolidated material
Earthquake
loose materials covering the surface of the Earth
Soil
unconsolidated rocky material covering bedrock
Regolith
mass of bedrock
Rock
freefall of detached individual pieces of any size
common in very steep slopes
Fall
presence of distinct zone of weakness separating the slide material form the more stable underlying material
types: rotational and translational
Slide
material moves downslope as a viscous fluid
usually saturated with water
Flow
downward sliding of a mass of rock or unconsolidated material along a curved surface
Slump
blocks of bedrock break loose and slide down a slope
Rockslide
relatively rapid flow of soil and regolith containing large amount of water
Debris flow
viscous downslope movement of saturated clay and silt on hillsides in humid areas
Earthflow
gradual downhill movement of soil and regolith due to alternating expansion and contraction of surface
Creep
occurs when soil is saturated with water and cannot escape
Solifluction
