Erosion

the physical removal

and

transporting

of rock material

by natural agents

such as

water, wind or ice.

Erosion due to rivers during flood stage.

Farm fields and crops eroded due to poorly draining soil, or topography

Shoreline erosion due to wave action of water

Down-cutting of river has eroded the canyon

Wind erosionWind-blown sand (silica) erodes

softer rock (shale , limestone) leaving behind the more resistant sandstone

Glacial erosionRock trapped in moving ice scrape and carve striations in bedrock.

Sec. 12.3

Mass Wasting

And Erosion

Type of mass movement

Amount of water Time / speed Composition Causes

Creep    

       

Slump    

       

Earthflow    

       

Mudflow    

       

 Lahar

       

12.3 Mass Movement (pg. 268-270)

Types of Mass Movement

These are all types of Landslides!!!!!

• Creep:

• Slump:

• Earthflow:

• Mudflow:

Types of mass Wasting

Factors that Effect Landslides

• Water/rainfall

• Composition of the ground

• Amount of loose weathered material

Triggers:

• Earthquakes

• Gravity/steepness of the slope

• Erosion (undercutting)

Rock slide

Rock slides: rock falls suddenly (without need for water), due to gravity

Talus: loose rock fragments that are pulled down by gravity

and pile-up at the base steep slopes.

Creep

Soil creep

Soil Slump

A river bank that has “slumped”

Soil Slump

Debris flow / earth flow

The remains of the massive landslide are seen on Monday, March 24 2014. The landslide blocked the highway and the Stillaguamish River.

http://www.youtube.com/watch?v=dVSXm13jH1s

Mud flow

Mud flow

Mt. St. Helen volcanic ash lahar

Volcanic ash and water:

Lahar

Sorting activityA

mou

nt o

f w

ater

/ra

infa

ll

Rate / speed of movement