1. Lecture Outlines Physical Geology, 14/e Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plummer, Carlson & Hammersley

2. Mass Wasting Physical Geology 14/e, Chapter 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

3. GEOLOGIC TIME AGAIN… S1

4. MASS WASTING AKA LANDSLIDE S2

5. DANG! SHOULD HAVE LEFT SOONER… S3

6. ANATOMY OF A LANDSLIDE S4

7. ONE MORE GRATUITOUS PICTURE… S5

8. Mass wasting – downhill movement of masses of bedrock, rock debris or soil, driven by the pull of gravity landslides have been far more costly in the U.S., in terms of both lives and dollars, than all other geologic and weather hazards combined mass wasting is, with proper planning, perhaps the most easily avoidable of all major geologic hazards Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mass Wasting s6

9. Rate of movement 100 km/hour Type of material solid bedrock or debris (unconsolidated material at Earth’s surface) Type of movement flow, slide, or fall Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Classification of mass wasting s7

10. S8 TYPE OF MOVEMENT

11. SO THIS IS? S8A

12. Flow – descending mass moves downhill as a viscous fluid Slide – descending mass remains relatively intact, and descends along well- defined surfaces translational slide - movement along plane parallel to motion rotational slide (slump) – movement along a curved surface Fall – material free-falls or bounces down a cliff Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Types of movement s9

13. PHYSICS REVIEW S10

14. Steep slopes – shear forces maximized by gravity Large relief – large elevation change from top of mountains/hills to valley floor Thick layer(s) of loose rock, debris, soil Presence of water – lubricant Lack of vegetation – no roots to hold rock/soil in place Seismic (earthquake) activity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Factors controlling mass wasting s11

15. POLYMORPHISM

16. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Factors controlling mass wasting s12

17. Creep (or soil creep) very slow downslope movement of soil major contributing factors include water in soil and daily freeze-thaw cycles can be costly to maintain homes, etc., on creeping ground as foundations, walls, pipes and driveways crack and shift downslope over time Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Common types of mass wasting s13

18. CREEP S14

19. HOW CREEPY? S15

20. Debris flow - mass wasting in which motion takes place throughout the moving mass earthflow - debris moves downslope, slowly or rapidly, as a viscous fluid mudflow - flowing mixture of debris and water, usually down a channel debris avalanches are very rapid and turbulent Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Common types of mass wasting s16

21. DEBRIS FLOW S17

22. Rockfall - when a block of bedrock breaks free and falls or bounces down a cliff commonly an apron of fallen rock fragments (talus) accumulates at cliff base Rockslide - the rapid sliding of a mass of bedrock along an inclined surface of weakness Rock avalanche - a very rapidly moving, turbulent mass of broken-up bedrock Debris slide - a coherent mass of debris moving along a well-defined surface Debris fall - a free-falling mass of debris Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Types of Mass wasting s18

23. GOOD BEDROCK = LESS MASS WASTING?

24. 1.Construct retaining wall with drains 2.Don’t oversteepen slopes during construction 3.Remove all rock that is prone to sliding 4. Stitch together outcrop Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Preventing Landslides s18 It is important to know the susceptibility of land to mass wasting before building any road or structure!

25. PREVENTING MASS WASTING S19

26. FRENCH DRAIN S20

27. THOUGHTS ON ROAD CONSTRUCTION S21

28. S22 HOW TO STABILIZE A HILLSIDE

29. End of Chapter 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.