1. MASS WASTING: The removal of weathered rock and soil.
More than 100x more destructive in U.S. than earthquakes and volcanoes combined!!!

2. Major Influences
* Water - too much vs. too little
* removal of vegetation (human-causes, forest fires, drought)
* stream undercutting (changes the slope)
* alternating freezing and thawing
* earthquake vibrations
* type of bedrock, direction of bedding or jointing

3. 1st Rule of Geology: Rocks Fall Downhill

4. Rockfall

5. Demonstration of “Angle of Repose” – Usually about 30

6. Landslide
Ex/ Gros Ventre River, Wyoming, was dammed by landslide in 1925.
The dam burst 2 years later, wiping out the town of Kelly, Wyoming.

7. Landslide

8. Slump
(Listric fault)
Often initiated by over-saturation.

9. Slump

10. Slumping on Mars

11. Slump
Major hazard along many coastlines

12. Mudflow
Often about 30% water
Can occur on slopes less than 5
Can be >100 m thick, and >100 km long

13. Mudflow (lahar)
(Pinatubo, 1991)

14. Creep
Typically 1-2 mm/yr, but can be as great as 10 cm/yr in cold or semi-arid regions

15. Creep

16. Creep

17. Underwater flows
Can cover 100,000’s of square kilometers.
Can flow over slopes of less than 1 at speeds of more than 100 km/hr.
Ex/ Cable breaks at Grand Banks, Newfoundland, 1929.

18. Massive landslides in places like the Canary Islands could cause enormous tsunamis

19. Ex/ Puerto Rico Trench

20. Weathering/Mass Wasting – Responsible for the appearance of the land surface.

31. Stream Tributaries

35. Fractal nature of tributaries

36. Major Streams of the world

37. Major drainage basins of the world

38. Components of a Stream:
Discharge
Slope
Velocity
Sediment Load

41. Effect of urbanization on stream run-off

42. Stream Gradient

43. Stream Gradient Mostly erosion Erosion and deposition
Mostly deposition

45. Dams: Many positive and negative aspects

46. Stream down-cutting works together with mass wasting

50. Differential erosion

53. Stream velocities fastest at the outside of a turn

54. Development of stream meanders and oxbow lakes

57. Floodplain features

58. Incised meander: San Juan River, Utah

59. Flooding – can carry MOST of the sediment of a stream
Mississippi River, 1993