1. Landslides & Related Phenomena http://www.youtube.com/watch?v=mknStAMia0Q

2. Landslides & Related Phenomena http://www.youtube.com/watch?v=mknStAMia0Q http://www.youtube.com/watch?v=F31ywRvtNkY

3. Introduction to Landslides Landslide – rapid downslope movement of “coherent” mass Slope failure/mass wasting- general term (e.g. mudflows, rockfalls, snow/debris avalanches) Subsidence (downward movement)

4. Introduction to Landslides

5. Slope Processes and Slope Stability “If it’s not a river or a beach, it’s a hillslope, of one ilk or another” –Most common landforms –Appear static; actually are dynamic Valley –Moving downhill Creep Avalanche/rock fall –Moderate events are the most important Magnitude Frequency

6. Slope Processes and Slope Stability Processes –Slope elements Convex slope/crest Free-face –Angle of repose Debris slope Convex slope/wash slope

7. Angle of repose: particle size particle shape moisture content Angle of Repose

8. Slope Processes and Slope Stability Processes –Slope movements or deformation Flowage/flow Sliding Falling Subsidence Classification –Type of movement –Slope material –Amount of water present –Rate of movement

9. Classification of Mass Movement Creep

10. Types of Movement

11. Slope Movements

12. Slope Stability When does a slope fail? What is the critical threshold that’s exceeded? Variables: –Material type –Slope –Topography –Climate –Vegetation –Water** –Time.

13. Landslides & Related Phenomena http://www.impactlab.com/2008/10/12/the-heyelan-land-slide/

14. Slope Stability Forces on Slopes –Driving forces--tend to move material down slope Weight of material (includes water)* Vegetation Fill material Building loads C D W N Potential slip plane (clay). ROCK A D = W sin A = driving force the downslope component of gravity.

15. Slope Stability Forces on Slopes –Resisting forces--forces that tend to resist movement Shear strength C D W N Potential slip plane (clay). ROCK A N = W cos A = the normal component of W contributes to the shear strength along the slip plane contributes to the resisting force.