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 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.
A river bank that has “slumped”
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
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