1. 4 FACTORS THAT CAUSE EROSION: GRAVITY RUNNING WATER WIND GLACIERS

2. EROSION FROM GRAVITY
**LANDSLIDES
**MUDFLOWS
**SLUMP
**CREEP

3. LANDSLIDES
Most destructive

4. MUDFLOWS (MUDSLIDES) Occurs after heavy rains Soil high in clay
Soil is saturated

5. SLUMP 1 huge chunk of land moves down
SLUMP
                                                                                          
1 huge chunk of land moves down
Occurs when water soaks the bottom of soil rich in clay

6. CREEP Very slow movement of soil
Occurs after freezing and thawing of water beneath the surface

7. EROSION FROM RUNNING WATER
SURFACE EROSION
GROUND WATER
WAVES

8. SURFACE WATER EROSION Run-off: Water that moves over Earth’s surface
Amount depends on:
Amt of rain
Amt of vegetation
Type of soil
Steep or flat
Use of land (parking lots, etc)

9. Types of Surface Water Erosion
Rill:
A small stream that forms during a heavy rain

10. GULLY Gully: a large groove or channel that forms during a heavy rain
Rills join to form gullies
Only has water during a heavy rain

11. STREAMS
Streams:
Rarely dry up
Gullies join to form streams

12. RIVERS
Rivers result when streams join together

13. TRIBUTARY: Streams & rivers that flow into a larger river

14. Rills join to form gullies; Gullies join to form streams; Streams join to form rivers.

15. Rills are tributaries for gullies; Gullies are tributaries for streams; Streams are tributaries for a river

16. GROUND WATER
Water that doesn’t evaporate and soaks into the ground

17. GROUND WATER EROSION
Ground water erosion is caused by chemical weathering
Water soaks into the ground, combines with CO2, forms weak acid and dissolves limestone forming caves

18. EROSION BY WAVES
Waves break down rock and transfer sand and sediments

19. Waves are produced by wind
The size of a wave depends on:
*How long the wind
blows
*How fast the wind
How far the wind

20. Waves move energy from place to place but not water.
Water molecules move
in circles and end up
where they started

21. Parts of a wave

22. As the wave nears shore, the friction slows the wave down
As the wave nears shore, the friction slows the wave down. Wave length gets shorter, height gets higher, wave “falls over.” It is now a breaker.

23. Weakest kind of erosion
EROSION CAUSED BY WIND
Weakest kind of erosion

25. Wind caused this “deflation” which resulted in this hollow left behind from wind erosion

26. Model of wind erosion

27. All sediments are eventually
deposited by falling to the
ground

28. REVIEW There are 4 factors causing erosion:
Gravity (landslides, mudflows, slump, creep)
Running Water (surface erosion, ground water, waves)
Wind
Glaciers

29. Check your knowledge quiz:
Landslide, mudflow, slump or creep?

30. Landslide, mudflow, slump or creep?

31. Landslide, mudflow, slump or creep?

32. Landslide, mudflow, slump or creep?

33. Rill, gully, stream or river?

34. Rill, gully, stream or river?

35. Rill, gully, stream or river?

36. Rill, gully, stream or river?

37. 1. Caves are formed from _______________
2. Waves are produced from _____________
Wave sizes are dependent on how______, how _____ & how ______ the wind blows.
The weakest form of erosion is_______
Why do waves break?
What are the parts to a wave?
Waves move __________ but NOT _____