1. MASS WASTING Movement of material due to gravity
Causes more property damage than all other geological disasters

2. Slopes Factors: (1)Slope material and (2) angle
steeper = more likely to move
less friction between particles = more likely to move
“angle of repose”

3. Which material would you expect to have the highest angle of repose?
Sand grains B. glass beads C. marbles D: broken bricks
E. dice

4. (3) Water

5. (4) Vegetation

6. (5) Loading

7. (6) Vibration
Earthquakes
Loud Noises
Vehicles
Machinery

9. (7) Size of Slope
Bigger slopes less stable

10. (8) Underlying Structure

11. Wildfire in Santa Barbara Co, Calif. has burned 27,000 acres
Wildfire in Santa Barbara Co, Calif. has burned 27,000 acres. In the next few years this area will experience higher mass wasting than previously. Why?
Heat changed slope material
Firefighters vibrated slope
Water added to slope
Slope has been loaded
Vegetation removed

12. Types of Mass Wasting
Creep

13. Slump

14. Slide – Landslide, rockslide

15. Flows – debris flow, mudflow, earthflow, avalanche

16. Rock Fall

17. SOLUTIONS
Gabions

18. Fabric, mesh

19. Vegetation

20. Retaining Walls

21. Drainage

22. Recontouring

23. Diversion Structures

24. PRS
Which prevention technique has the lowest initial cost?
Gabions B. Diversion structures C. Recontouring
D. Retaining Walls E. Vegetation

25. I - 40
What mistakes were made?

26. I – 40 Example

27. What’s wrong here?

28. Yungay, Peru May 31, 1970 50,000,000 m3 @ 200-400 km/hr killed 29,000

29. Yungay, Peru

32. Group Question
What could have been done to prevent/minimize the damage?

33. Gros Ventre, Wyoming, 1925 37,000,000 m 50-80 mph dammed river

35. Group Question
What could have been done to prevent/minimize the damage?