Verified Test Bank Ch13 Unsafe Ground Landslides and Other

CHAPTER 13: Unsafe Ground: Landslides and Other Mass Movements

LEARNING OBJECTIVES

13A. Identify different types of mass movements, and explain the differences among them.

13B. Sketch a model illustrating the forces acting on the material of a slope, and discuss factors that determine whether a slope is stable or unstable.

13C. Describe the evidence that major mass movements have taken place under the sea, and that some of these movements triggered tsunamis.

13D. Highlight events that may trigger mass movements, and explain why some regions are particularly susceptible to mass movement events.

13E. Evaluate hazards related to mass movements, and discuss how such hazards can, in some cases, be prevented.

MULTIPLE CHOICE

1. Mass wasting is the downslope movement of

2. Regolith consists of __________.

3. Mass movements are driven by __________.

4. Geologists distinguish among different types of mass wasting based on factors such as the ________ of the moving material and the rate of movement.

5. Which of the following types of mass movement takes place most gradually?

6. Which of the following types of mass movement is least coherent (most fluid-like)?

7. Slumps typically arrive ________ at the bottom of a slope.

8. Which of the following types of mass movement often travels down a curved surface?

9. ________ occurs when debris or snow mixes with air to form a chaotic cloud.

10. Lahars occur on ________.

11. A ________ may form at the head of a slump.

12. The principal difference between a debris flow and a mudflow is ________.

13. The principal difference between a lahar and a mudflow is ________.

14. The principal difference between a slump and a debris slide is ________.

15. What type of mass wasting event is beginning to form on the hillside shown in the image below?

16. What is happening to the hillside in the tundra pictured below?

17. Tree trunks that have a pronounced curvature at their base are indicative of ___________.

18. Identify the toe of the slump in the image below.

19. Identify the failure surface in the image below.

20. Why do submarine slumps pose a hazard to people living in coastal areas?

21. In a _________, submarine sediments flow downslope as a suspended cloud dispersed in water.

22. The immediate cause of incidents of mass movement is ________.

23. As shown in the figure below, ________ may form parallel to slope surfaces in granite and become a failure surface.

24. The ________ in the sequence of sedimentary rocks shown below may become a failure surface.

25. Unstable slopes start to move when the ________ force exceeds the ________ force that holds the material in place.

26. A slope made of irregularly shaped gravel is likely to _______ compared to a slope of well-rounded sand.

27. Well-rounded sand has a smaller ________ than irregularly shaped gravel.

28. Moisture among sediment grains ________.

29. You are a geologist trying to determine if the slope your client’s house sits on is stable. You determine that the angle of repose of the hillside is 35°. Which of the following situations would be considered stable?

30. Adding a small amount of water to a substance increases its cohesion, whereas adding a lot of water decreases its cohesion. Why?

31. Which of the following increases the risk of mass movement?

32. Which of the following situations would be the most susceptible to slope failure?

33. Which of the following situations would be the least susceptible to slope failure?

34. Where is liquefaction most likely to occur following an earthquake?

35. Weathering is a failure trigger because it ____________ of the material.

36. Why does the removal of material at the base of a slope decrease its stability?

37. Ground shaking can transform wet sediments into liquid-like slurries in a process known as ________.

38. ________ can occur where undercutting by waves or rivers removes support from beneath cliff overhangs.

39. The most important factor in determining if an area will be subject to mass movement is _______.

40. Which of the following landscapes is the most likely candidate for the occurrence of mass movements?

41. Which areas are most susceptible to slope failure?

42. Slope failures are most likely to occur in ________ conditions.

43. Slope failures are more likely to occur in ________ than in ________.

44. Which of the following factors decreases the risk of mass movement?

45. After finishing a new construction project, why is the first task often to install new landscaping around the area?

46. In the figure below, what would be the most effective way to stabilize the slope, assuming that the slope is in a dry, desert environment?

47. Which of the following consist(s) of large boulders placed at the base of coastal slopes?

48. Construction workers often cut benches or terraces, such as those seen in the image below, along the sides of roads to help mitigate landslides. This is because terraces

49. How can you use a landslide hazard map to help buy a piece of property?

50. What is the most effective means of mitigating the risk of a slope failure for the slope shown in the figure below?

1. Compare and contrast a debris flow and a debris fall.

2. Examine the photograph below. What type of mass wasting event is beginning to take place here? How can you tell?

3. What is a turbidity current? How is this related to mass movements?

4. Why are submarine mass wasting events of concern to people living near sea level in coastal regions? (What hazard can be triggered by submarine mass wasting events?)

5. What is the resistance force, and what things can cause it? What happens when the resistance force exceeds the downslope force? What happens when the downslope force exceeds the resistance force?

6. Describe two factors that affect the resistance force and explain how they affect the stability of the slope.

7. How can the amount of water play a role in slope stability and slope failure?

8. Why would Florida, which receives plentiful rainfall and remains humid for a large portion of the year, be less susceptible to landslides than the California desert?

9. Notice the cliff in the image below. Is this cliff stable? Why or why not? What could be done to increase the stability of the cliff?

10. Describe two ways of mitigating landslide hazards and describe how they work and what issues they may have.