1. Erosion
Gravity Wins

2. What is Erosion? (notes)
The movement of weathered material.
Gravity
Streams
Glaciers
Wind

3. Erosion by Gravity – Mass Wasting
Inertia is the force which keeps things from wanting to move. (Friction)
Gravity is the force pulling objects toward the center of the Earth.
When Gravity is greater than Inertia –
LANDSLIDES!!

4. Mass Wasting - Classification
Rate of movement – how fast is it moving?
Type of movement – how is it moving?
Type of material – what is moving?

5. Soil Creep (notes)
Soil VERY SLOWLY slides downhill.
Not noticeable over short periods of time
Areas with heavy rain storms or other disturbances.

7. Creeping Headstones

8. Earthflow (notes)
Faster than creep
Very wet soil = little friction between top layer of soil and bottom
Top layer slides downhill

9. Earthflow Structure
Flow Only
Flow with Rotation

10. Mudflow (notes)
Even Faster
Intense amounts of water + soil and rocks = MUD
Very thick liquid mixture flows downhill
Very powerful, damaging

12. Dried Mudflow

13. Mudflow

14. A line of weakness on a slope appears
Slump (notes)
Happens all at once
A line of weakness on a slope appears
A huge block of earth slips downhill
*Not good if you built your house on a cliff edge*

16. Rock Slide and Falls(notes)
Chunks of rock break off hillside or cliff
Bounce or roll down hill
Caused by earthquakes, frost wedging, wave cutting, etc.
DEVASTATING DAMAGE

17. Rock Slides and Falls

18. Rockfall in action

19. Rock Slide

20. Preventing Landslides

21. Poor Road Design

22. Improved Drainage Less Creep

23. Speed Summary
CREEP
EARTHFLOW
MUDFLOW
SLUMP
ROCK FALL
SLOW
FAST