1. Surface Processes Mass Wasting Streams Ground Water (Glaciers) (Shorelines) (Deserts)

2. Monument Valley, Arizona

3. Stream Carved Landscapes

4. Three Sisters, Cascades, Oregon

5. Denali National Park, by Berann

6. Yosemite, Bridal Vail Falls

7. Karst Topography from GW action

8. XI. Mass Wasting A.Classifications (Definitions, processes and controlling factors) B.Examples (Appling knowledge of processes) C.Prevention of Mass Wasting (limiting and eliminating)

9. Flow Fall Classification of Mass Wasting Slide

10. Classification of Mass Wasting Type of Movement Classification Material Velocity Creep DebrisImperceptibly Slow Earth Flow Debris Slope and Material Dependent <5 km/hr Mudflow Saturated Debris Avalanche Debris or RockVery Fast 100 km/hr Rotational Slide DebrisSlow-mod. (short) Rock Slide BedrockFast Debris Fall DebrisFast Flow Slide Fall Rockfall BedrockFast

11. Creep Imperceptibly slow flow Expansion - contraction Heating – Cooling Freeze – Thaw

12. Earth Flow and Rotational Slide Debris (soil) both slides and flows Sliding Rotation (tilting) Scarp Flow Mixing Hum- mocks

13. Rock Slide and Fall Bedrock may slide and/or fall Weathering reduces bedrock strength Eventually gravity wins

14. Talus Slopes The result of Mechanical weathering Rock falls and slides Crushing and abrasion (more mechanical weathering) Rock Avalanches Slopes of rock fragments may let go and careen downhill as a very fast flow

15. Mass Wasting, Who Cares? Geology in the news? How does it effect you? (Environmental Geology) Know where to look Understand risks Reduce and prevent risks Improve engineering We need to understand how mass wasting works

16. Shear Force vs. Shear Strength Driving Forces i.e., Shear Force Component of Gravity Other forces Resisting Forces i.e., Shear Strength Fiction and Adhesion Soil or Rock

17. Mt. St. Helens Landslide triggers eruption Reduced shear strength from earthquakes and bulging Increased shear force as bulge grows and slopes steepen Eruption causes Mudflows

19. Gros Vantre Slide Sandstone and debris on Impermeable shale Saturation of sandstone and lubrication of shale Both reduced shear strength (added to shear force) Shear force overcomes shear strength Sandstone and debris slide

20. Use Knowledge of Mass Wasting to Avoid Risks Be able to recognize geologically unstable situations

21. Understanding Mass Wasting Development causes: Increased shear force Steepened slope Added weight Decreased shear strength Devegetation Reworking of fill Saturation of soil

22. Reduce Risks Some solutions include: Increase shear strength Re-compact soils Re-vegetate soil slopes Construct retaining wall with anchors Prevent Saturation Prohibit over-irrigation Install surface drains Install subsurface drains

23. Increase shear strength with iron rods and anchors Remove risk Reduce Risks

24. Examples of Mass Wasting The Old Man of the Mountain, Cannon Mtn. NH

25. X. Streams A.The Hydrologic Cycle (components and pathways) B.Stream Velocity (controls and results) C.Drainage Patterns and Landscape Features (results of erosion and deposition) D.Stream Valley Development (tectonic uplift and downcutting)

26. The Hydrologic Cycle See Fig. 12.3

27. Systems of streams and their tributaries that collect runoff Divide Ground Water Drainage Basins Great Lakes Drainage Basin

28. Steam Profiles (Streams Shaping the Land) V-Shaped Valley Flood Plain

29. What is this Drainage Pattern? (What does is tell of the geology?)

30. Valley and Ridge Province of PA (Trellis Stream Patters)

31. Stream Gradient Slope of the land Sinuosity of stream 10 m/km 10 m per 1¼ km = 8 m/km 10 m 1 km 10 m 1 km

32. Meander Velocity Higher velocities on outside of meanders causes erosion (cut bank) Lower velocities on inside of meanders causes deposition (point bar) Fig. 10.6

33. Channel Shape and Roughness A. Narrow and Deep Less resistance Faster flow B. Wide and Shallow More resistance Slower flow C. Rough Streambed More resistance Slower flow

34. Stream Velocity Controls: Erosion Transport Deposition

35. Stream Erosion Then, Erosion Solution (chemical weathering) Hydraulic Action (lifting) Abrasion (crushing and grinding) Fig 10.11 First, Weathering Fracturing (mechanical) Loosening (mechanical and chemical) Solution (chemical)

36. Stream Transport Dissolved Load Suspended Load Bed Load Saltation Rolling, sliding Fig10.14 (ions)

37. Stream Deposition Braided Streams Alluvial Fan e.g., Alluvial Fans Fig. 10.31 Fig. 10.19 Erosion Dominated High gradients Less resistance Fast velocities Deposition Dominated Lower gradients More resistance Lower velocities

38. Stream Deposition Midchannel bars Fig. 10.18a Point bars Fig 10.22b Braided streams Fig. 10.18b

39. Deltas Fig. 10.28 Reduction of velocity due to extreme widening Deposition of silt and clay

40. Erosion and Deposition  Transport E.g., Meandering streams As meanders are migrating Cutbanks eroding Point bars building Sediment is moving downstream

41. Meander Cutoff How does the gradient change with meandering and meander cutoff?

42. Meandering Streams Identify Cutbanks Point bars Meander neck Oxbow lakes Areas of Erosion Areas of Deposition Fig. 10.20 A A B B C C D D E E

43. Flooding Overbank deposits Widening of stream into flood plain Deposition of sediment Coarse near stream Fine farther away Natural Levees Fig. 10.27

44. Graded Streams Increased velocity and accelerated erosion. Erosion acts to grade the Longitudinal stream profile to concave-upward curve Base level: Lake or Sea Same Base level

45. Drainage Patterns Geology controls stream patterns A.Uniformly Erodible (e.g., flat-lying sedimentary rocks of the Midwest) B.Conical Mountains (e.g., Volcanoes) C.Fractured bedrock (shallow bedrock) D.Resistant ridges of tilted sedimentary rocks (e.g., Valley and Ridge Province of Pennsylvania) A. Dendritic B. Radial C. Rectangular D. Trellis