WHAT IS MASS MOVEMENT?
WHAT IS MASS MOVEMENT?. Downslope movement of Earth material under the influence of gravity.
Dec 16, 2015
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WHAT IS MASS MOVEMENT?
WHAT IS MASS MOVEMENT?
Downslope movement of Earth material under the influence of gravity.
Downslope
Downslope
Earth material(not alien!)
Downslope
Earth material(not alien!)
Gravity
THE BIG PICTURE
Uplift – Creation of potential energy by
forces from within the
Earth
THE BIG PICTURE
Erosion of materials
from uplands to low land by gravity and other external forces.
Uplift – Creation of Potential Energy by
forces from within the
Earth.
WHAT ARE THE TYPES OF MASS MOVEMENT?
1. Slides:
2. Flows:
3. Heaves:
WHAT ARE THE TYPES OF MASS MOVEMENT?
1. Slides:
2. Flows:
WHAT ARE THE TYPES OF MASS MOVEMENT?
1. Slides:
2. Flows:
3. Heaves:
WHAT ARE THE TYPES OF MASS MOVEMENT?
1. Slides: All the vertical displacement occurs along a single plane.
2. Flows:
3. Heaves:
WHAT ARE THE TYPES OF MASS MOVEMENT?
1. Slides: All the vertical displacement occurs along a single plane.
2. Flows: Vertical displacement occurs throughout the moving material.
3. Heaves:
WHAT ARE THE TYPES OF MASS MOVEMENT?
1. Slides: All the vertical displacement occurs along a single plane.
2. Flows: Vertical displacement occurs throughout the moving material.
3. Heaves: Displacement by means of non-cancelling vertical movement of material.
SLIDE
ShearPlane
Toe
All of downslope displacement (with small exception of the “toe”) occurs
along a single plane, the “shear plane”.
ITALIAN DISASTER!Mini-tsunamiVajont Dam burst1963
Vajont Dam Burst, 1963
Over-toppeddam
Landslide scar
Landslide toe
Reservoir shoreline
FLOW
All of downslope displacement occurs throughout the moving body.
HEAVE
1. Uplift: Perpendicular to slope.
2. Collapse: Vertically under the influence of gravity.
1. Uplift: Perpendicular to slope.
2. Collapse: Vertically under the influence of gravity.
1. Uplift: Perpendicular to slope.
Resultant Vector:Downslope movement
UPLIFT COLLAPSE
1.
2.
3.
UPLIFT COLLAPSE
1. HEATING
2.
3.
Ground heat fluxExpansion
UPLIFT COLLAPSE
1. HEATING
2.
3.
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
UPLIFT COLLAPSE
1. HEATING
2. WETTING
3.
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
Clays expand when wet
Clay Minerals occur in sheets, or “Laminae”.
Water molecules get inserted between sheets causing expansion
UPLIFT COLLAPSE
1. HEATING
2. WETTING
3.
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
Clays expand when wetDRYINGWater dries and sheets Contract.
UPLIFT COLLAPSE
1. HEATING
2. WETTING
3. FREEZING
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
Clays expand when wetDRYINGWater dries and sheets Contract.
Soil water freezes and expands
Like most substances the density of water increases as
temperature decreases.
After 4°C (39°F) strange things happen – the density
decreases!!!!!
Once ice forms density drops to about .917!
ICE IS ABOUT 90% OF THE DENSITY OF – SO IT FLOATS IN WATER
At warmer temperatures the random motions caused by heat disrupt the tendency for water molecules to align
As temperatures cool the bonds between adjacent molecules dominate and water adopts a regular structure.
Density = Mass / Volume
Consider fixed mass of water (1 gram) in soil pore andDensity of water = 1 gram /cc (cubic centimeter), then water occupies 1 cc.
Temperature at night drops below 0°C (32°F), so water turns to ice, with a density of 0.92 gram/cc
0.92 = 1 gram/ VolumeVolume = 1/ 0.92 = 1.09 ccs
By freezing water increased the volume it occupies by about 9%
Density = Mass / Volume
Consider fixed mass of water (1 gram) in soil pore andDensity of water = 1 gram /cc (cubic centimeter), then water occupies 1 cc.
Temperature at night drops below 0°C (32°F), so water turns to ice, with a density of 0.92 gram/cc
0.92 = 1 gram/ VolumeVolume = 1/ 0.92 = 1.09 ccs
By freezing water increased the volume it occupies by about 9%
Density = Mass / Volume
Consider fixed mass of water (1 gram) in soil pore andDensity of water = 1 gram /cc (cubic centimeter), then water occupies 1 cc.
Temperature at night drops below 0°C (32°F), so water turns to ice, with a density of 0.92 gram/cc
0.92 = 1 gram/ VolumeVolume = 1/ 0.92 = 1.09 ccs
By freezing water increased the volume it occupies by about 9%
Density = Mass / Volume
Consider fixed mass of water (1 gram) in soil pore andDensity of water = 1 gram /cc (cubic centimeter), then water occupies 1 cc.
Temperature at night drops below 0°C (32°F), so water turns to ice, with a density of 0.92 gram/cc
0.92 = 1 gram/ VolumeVolume = 1/ 0.92 = 1.09 cc
By freezing water increased the volume it occupies by about 9%
Density = Mass / Volume
Consider fixed mass of water (1 gram) in soil pore andDensity of water = 1 gram /cc (cubic centimeter), then water occupies 1 cc.
Temperature at night drops below 0°C (32°F), so water turns to ice, with a density of 0.92 gram/cc
0.92 = 1 gram/ VolumeVolume = 1/ 0.92 = 1.09 ccs
By freezing water increased the volume it occupies by about 9%
UPLIFT COLLAPSE
1. HEATING
2. WETTING
3. FREEZING
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
Clays expand when wetDRYINGWater dries and sheets Contract.
Soil water freezes and expands
THAWINGIce melts and occupies a smaller volume
UPLIFT COLLAPSE
1. HEATING
2. WETTING
3. FREEZING
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
Clays expand when wetDRYINGWater dries and sheets Contract.
Soil water freezes and expands
THAWINGIce melts and occupies a smaller volume
“Dry Heaves”
UPLIFT COLLAPSE
1. HEATING
2. WETTING
3. FREEZING
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
Clays expand when wetDRYINGWater dries and sheets Contract.
Soil water freezes and expands
THAWINGIce melts and occupies a smaller volume
“Dry Heaves”
“Wet Heaves”
UPLIFT COLLAPSE
1. HEATING
2. WETTING
3. FREEZING
Ground heat fluxExpansion
COOLINGNighttimeRadiative coolingContraction
Clays expand when wetDRYINGWater dries and sheets Contract.
Soil water freezes and expands
THAWINGIce melts and occupies a smaller volume
“Dry Heaves”
“Wet Heaves”
“Cold Heaves”
HOW DO MASS MOVEMENTPROCESSES DEMONSTRATE THE
IMPORTANCE OF THE MAGNITUDEAND FREQUENCY OF FORCES IN
SHAPING THE LANDSCAPE?
GEOMORPHOLOGY – STUDY OF THE SHAPE OF THE EARTH’S SURFACE
“How much work does a particular process (slides, flows, creeps) complete in shaping the
surface of the Earth?”
WorkCompleted
= Magnitudeof Process X Frequency
of Process
TotalYards
= Yards perCarry X Carries per
Game
100 yds = 2 X 50
100 yds = 10 X 10
Fullback
Runningback
WorkCompleted
= Magnitudeof Process X Frequency
of Process
TotalYards
= Yards perCarry X Carries per
Game
100 yds = 2 X 50
100 yds = 10 X 10
Fullback
Runningback
WorkCompleted
= Magnitudeof Process X Frequency
of Process
TotalYards
= Yards perCarry X Carries per
Game
100 yds = 2 X 50
100 yds = 10 X 10
Fullback
Runningback
WorkCompleted
= Magnitudeof Process X Frequency
of Process
TotalYards
= Yards perCarry X Carries per
Game
100 yds = 2 X 50
100 yds = 10 X 10
Fullback
Runningback
Low magnitude
Low frequency
High magnitude
High frequency
WorkCompleted
= Magnitudeof Process X Frequency
of Process
Creep/Heave
Flow/Slide
Low magnitude
Low frequency
High magnitude
High frequency
WorkCompleted
= Magnitudeof Process X Frequency
of Process
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