1. MASS WASTING AND MASS MOVEMENT
• mass movement - a general term used to describe the downhill movement of material that are known as slides, falls, slumps, flows, and creep

2. MASS WASTING AND MASS MOVEMENT
1. unconsolidated material - those that are loose or uncemented, such as sand and soil
2. consolidated material - those that are compacted, cemented, or vegetated soils

3. • Factors That Influence Mass Movement
1.slope of material - the steepness of a slope influences instability in mass movement
the steepness of a pile of loose material such as sand has a distinct limit - angle of repose
once the angle of repose is reached, addition of more sand will make the pile broader but not taller

4. • Factors That Influence Mass Movement
2. internal friction - a material’s total resistance to movement
i. consolidated dry materials are held together by cohesion (attraction of like particles) and adhesion (attraction of unlike particles)
ii. cementation
iii. plant roots

5. • Factors That Influence Mass Movement
3. surface tension
4. moisture content
i. too little limits vegetation
ii. too much can push grains apart, add weight, or provide lubrication

6. • Factors That Influence Mass Movement

7. • Triggers of mass movement
1. sudden addition of moisture

8. • Triggers of mass movement
2. shaking of the ground - liquefaction

9. • Classification of mass movement
1. Based upon
i. nature of the material (rock or unconsolidated)
ii. speed of movement
iii. nature of movement (sliding, falling, or flowing)

10. • Rock Mass Movement
1. rockfall - free fall of boulders from a cliff

11. • Rock Mass Movement
2. rockslides - sliding of rock down an incline
i. usually due to rock breaking from its host material along a bedding plane, joint, or other structural weakness

12. • Rock Mass Movement
3. talus - debris at the bottom of the slope in a broken mass due to rockfalls and rockslides

13. • Rock Mass Movement
4. rock avalanche - rock becomes broken into pieces before it reaches the foot of a slope

15. • Unconsolidated Material Mass Movement
1. creep - extremely slow, almost imperceptible downslope movement of soil and rock debris

17. • Unconsolidated Material Mass Movement
2. solifluction (soil flowage) - special type of creep that is common in polar regions where groundwater in the pore spaces of soil and rock is permanently frozen

18. • Unconsolidated Material Mass Movement
3. earthflows and debris flows - consist of mixtures of rock fragments, mud, and water that flow downslope as viscous fluids

19. • Unconsolidated Material Mass Movement
3. earthflows and debris flows - consist of mixtures of rock fragments, mud, and water that flow downslope as viscous fluids

21. • Unconsolidated Material Mass Movement
4. mudflows - a variety of debris flow that consist mostly of small silt and clay-sized particles
i. usually occur after heavy rain
ii. as much as 30% water content

23. • Unconsolidated Material Mass Movement
5. debris avalanche - fastest unconsolidated mass movement
i. on steep slopes in humid areas
6. slumps and debris slide - movement of material in which the material is not rearranged

25. Debris Slide

27. • Plate Tectonics
1. OC - CC boundary
i. causes steep slopes
ii. volcanic activity and earthquakes

28. Gros Ventre
1925
80 km / hr
Buried 30 m thick

30. • Impact of Human Activities on Mass Movement
1. road construction
2. reservoirs