WHAT IS MASS MOVEMENT?. Downslope movement of Earth material under the influence of gravity.

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