1. 3-1
Mass Movement
When slopes fail…

2. Once weathering has occurred, then erosion can take place.
REVIEW
Once weathering has occurred, then erosion can take place.
What is EROSION?

3. EROSION is the process of carrying away weathered rock.
The Grand Canyon is an example of what erosion can do!

4. Eventually most of the broken bits of rock end up in streams & rivers that flow down from the mountains. These little bits of rock & sand are called SEDIMENTS.

5. What is DEPOSITION?
DEPOSITION is the process of laying down weathered rocks in a new location.

6. Weathering, sediments, erosion and deposition work together in a cycle!

7. What is
Mass Movement?
Erosion & deposition of large amounts of sediment downhill, sediment is usually loose

8. How does Mass Movement work? By the force of gravity
Can be fast or slow

9. Landslide
La Conchita, CA 1995

10. Landslide
Close-up
La Conchita, CA 1995

11. Landslide
Looking down
La Conchita, CA 2005

12. Landslide

13. Landslide

14. Before
Landslide
Peru's Main Plaza Landslide's Destruction
After

15. Video of a Real Landslide in Japan

16. Video of a Rockslide in Tennessee

17. Happens when rock and soil break loose from steep slopes
1. LANDSLIDE (very fast)
Happens when rock and soil break loose from steep slopes
most destructive mass movement
falls quickly to the bottom
occur in mountainous areas
may contain huge masses of rock

19. Mudslide/Mudflow

20. Mudslide/Mudflow

21. Video of a Real Mudslide in California

22. Video of a Real Mudslide in Italy

23. 2. MUDSLIDE/MUDFLOW (very fast)
A thick mixture of sediments and
water flow down a slope
occur in dry areas where weathering forms thick layers of dry sediment
heavy rains mix with sediment to make mud
have enough energy to move anything in its path
at the bottom of slope, loses its energy of motion deposits all the sediments and debris it has been carrying

25. Bismarck, North Dakota 1987
Slump

26. Bismarck, North Dakota 1988 9 months later
Slump

27. Slump

28. Video of Real Slump over 8 days

29. 3. SLUMP (not fast)
Occurs when loose material or rock layers slip downward as one large mass
takes place as one large mass
doesn't move materials very fast or very far
curved scar (scarp) is left where slumped material was
occur because the clay under the slumped material weakens because it gets very wet
when it can no longer support overlying material it slips downhill

31. Creep

33. Creep

34. Gets its name from the way sediments slowly creep down a hill
4. CREEP (very slow)
Gets its name from the way sediments slowly creep down a hill
especially common in areas where freezing and thawing occur (ice wedging)
as the ground freezes, small sediments are pushed up by expanding water in the soil
when the soil thaws, the sediments fall downhill
trees, utility poles and fence posts lean or slant downhill