Chapter 6 Multiple Choice

 

  1. The elastic rebound theory for the origin of earthquakes was first proposed by ____________ following the ____________ earthquake.

      a. Reid; 1906, San Francisco                                   

      b. Giuseppe; 1925, Pizza Lake

      c. Richter; 1989, Loma Prieta                                  

      d. Mohorovicic; 1964, Anchorage

 

  2. When an earthquake occurs, energy radiates in all directions from its source. The source is also referred to as the __________.

      a. inertial point                    

      b. epicenter                        

      c. focus                             

      d. seismic zone

 

  3. Which one of the following statements is correct?

      a. P waves travel through solids; S waves do not.

      b. P and S waves travel through liquids, but P waves do not travel through solids.

      c. S waves travel through solids and P waves travel through liquids.

      d. P and S waves travel through liquids, but S waves do not travel through solids.

 

  4. ____________ have the highest velocities.

      a. Primary waves               

      b. Secondary waves           

      c. Surface waves               

      d. Refracted S waves

 

  5. Which one of the following is true regarding tsunamis?

                 a. they travel as deep-water waves at speeds greater than surface seismic waves but slower than S

                     waves

      b. their wave heights decrease and wavelengths increase as they move into shallower water

                 c. they are started by fault-induced, horizontal shifts in the sea floor that suddenly propel great masses

                     of water in opposite directions

                 d. they occur in the open ocean, wavelengths are many miles or kilometers and wave heights are only

                     a few feet

 

  6. The amount of destruction caused by earthquake vibrations is affected by __________.

      a. design of structures                                             

      b. intensity and duration of the vibrations

      c. nature of the surface material                              

      d. all of these

 

  7. On a typical seismogram, ____________ will show the highest amplitudes.

      a. P waves                         

      b. S waves                         

      c. surface waves                

      d. body waves

 

  8. Major earthquakes are often followed by somewhat smaller events known as __________.

      a. aftershocks                    

      b. foreshocks                     

      c. tremors                          

      d. hyposhocks

 

  9. The ____________ magnitude scale is a measure of the energy released. It does not directly measure the extent of building damage.

      a. Gutenberg                      

      b. Reid 

      c. Mercalli                         

      d. Richter

 

10.  The instrument which records earthquake events is termed a __________.

      a. polygraph                       

      b. thermograph                   

      c. seismograph                   

      d. barograph

 

11.  ____________ is the maximum possible damage designation on the Mercalli scale.

      a. XII  

      b. 12    

      c. X     

      d. 10

 

12. The position on Earth's surface directly above the earthquake source is called the __________.

      a. epicenter                        

      b. inertial point                    

      c. focus                             

      d. seismic zone

 

13.  The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed __________.

      a. elastic rebound               

      b. seismic rebound              

      c. fault displacement           

      d. stress fracture

 

14.  Overall, this type of seismic wave is the most destructive.

      a. P wave                          

      b. S wave                          

      c. surface wave                 

      d. tsunami

 

15.  Approximately how much more energy is released in a 6.5 Richter magnitude earthquake than in one with magnitude 5.5?

      a. 3000 times                      

      b. 3 times                           

      c. 300 times                       

      d. 30 times

 

16.  P waves ____________.

      a. propagate only in solids   

      b. are faster than S waves and surface waves

      c. have higher amplitudes than do S waves               

      d. produce the strongest ground shaking

 

17.  The Mercalli Scale is a scale from ____________.

      a. 1 to 12 that rates the energy required for faulting to occur

      b. 1 to 10 that rates the energy released by an earthquake

      c. I to XII that rates the structural damage due to an earthquake

      d. I to X that rates the total energy released during the main quake and all aftershocks

 

18.  The distance between a seismological recording station and the earthquake source is determined from the __________.

      a. earthquake magnitude                                         

      b. intensity of the earthquake

      c. length of the seismic record                                 

      d. arrival times of P and S waves

 

19.  The Richter magnitude of an earthquake is determined from the __________.

      a. duration of the earthquake                                   

      b. intensity of the earthquake

      c. arrival time of P and S waves                              

      d. amplitude of the surface waves

 

20.  Which one of the following best characterizes tsunamis?

      a. they cause the land to ripple and oscillate             

      b. they are faster than seismic surface waves

      c. they have relatively small amplitudes compared to their very long wavelengths

      d. they are easily seen at sea but are lost in the swell and breaking waves along a coast

 

21.  The ____________ earthquake was accompanied by extensive fire damage.

      a. Anchorage, 1964                                                

      b. San Francisco, 1906

      c. Mexico City, 1985                                               

      d. Yerevan, Armenia, 1988

 

22.  A ____________ refers to the tendency for a foundation material to lose its internal cohesion and fail mechanically during earthquake shaking.

      a. Slurrying                        

      b. Liquefaction                   

      c. Motion slip                     

      d. Seismoflowage

 

23.  The record of an earthquake obtained from a seismic instrument is a(n) __________.

      a. seismograph                   

      b. seismogram                    

      c. time-travel graph            

      d. epigraph

 

24.  Most of our knowledge about Earth's interior comes from __________.

      a. drill holes                                                            

      b. volcanic eruptions

      c. seismic waves                                                    

      d. examination of deep mine shafts

 

25.  Which one of the following statements about the crust is NOT true?

      a. it is the thinnest of the major subdivisions

      b. it is thickest where prominent mountains exist

      c. oceanic crust is enriched in potassium, sodium, and silicon

      d. continental rocks are compositionally different than oceanic rocks

 

26.  The dense core of Earth is thought to consist predominantly of __________.

      a. nickel                             

      b. lead

      c. iron

      d. copper

 

27.  The lithosphere is defined as __________.

      a. a rocky layer having a relatively uniform chemical composition

      b. a rigid layer of crustal and mantle material

      c. a rocky layer composed mainly of crustal rocks

      d. a plastic layer composed mainly of mantle material

 

28.  The average composition of the oceanic crust is thought to approximate that of __________.

      a. granite                           

      b. basalt                             

      c. peridotite                        

      d. iron

 

29.  The average composition of the continental crust most closely approximates that of __________.

      a. granite                           

      b. basalt                             

      c. peridotite                        

      d. iron

 

30.  The Earth’s magnetic field originates by ____________.

      a. weak electrical currents associated with hot, rising, mantle plumes

      b. magnetic mineral grains in the inner core

      c. weak electrical currents associated with fluid motions in the outer core

      d. magnetization of oxygen and nitrogen atoms in the atmospheric ozone layer by solar radiation

 

31.  The asthenosphere is located __________.

      a. within the crust                                                   

      b. in the upper mantle

      c. between the mantle and outer core                      

      d. within the outer core

 

32.  A ____________ fault has little or no vertical movements of the two blocks.

      a. stick slip                         

      b. oblique slip                     

      c. strike slip                        

      d. dip slip

 

33.  In a ____________ fault, the hanging wall block move up with respect to the footwall block.

      a. normal                           

      b. inverse                           

      c. reverse                          

      d. abnormal

 

34.  In thrust faulting, ____________.

      a. grabens develop on the footwall block

      b. the crust is shortened and thickened

      c. horizontal, tensional stresses drive the deformation

      d. the hanging wall block slips downward along the thrust fault

 

35.  A graben is characterized by ____________.

      a. a hanging wall block that has moved up between two reverse faults

      b. a footwall block that has moved up between two normal faults

      c. a hanging wall block that has moved down between two normal faults

      d. a footwall block that has moved down between two reverse faults

 

36.  The mountains and valleys of the Basin and Range Province of western United States formed in response to ____________.

      a. strike-slip faulting and hanging wall block uplifts

      b. reverse faults and large displacement, thrust faulting

      c. tensional stresses and normal-fault movements

      d. normal faulting and horizontal compression

 

37.  In a normal fault ____________.

      a. the hanging wall block below an inclined fault plane moves downward relative to the other block

      b. the footwall block below an inclined fault plane moves downward relative to the other block

      c. the hanging wall block above an inclined fault plane moves downward relative to the other block

      d. the footwall block above an inclined fault plane moves upward relative to the other block

 

38.  A transform fault is ____________.

      a. a strike-slip fault that forms the boundary between tectonic plates

      b. a dip-slip fault connecting an anticline with a syncline

      c. a reverse fault that steepens into a thrust fault

      d. the rift bounding faults on a mid-ocean ridge

 

39.  Brittle deformation would be favored over plastic deformation in which of the following conditions?

      a. high confining pressures  

      b. warmer temperatures      

      c. cooler temperatures                                            

      d. shallow depths

 

40.  A thrust fault is best described as ____________.

      a. a steeply inclined, oblique-slip fault                       

      b. a low-angle, reverse fault

      c. a vertical, normal fault     

      d. a near vertical, strike-slip fault

 

41.  A horst is ____________.

      a. an uplifted block bounded by two normal faults

      b. a downdropped block bounded by two reverse faults

      c. an uplifted block bounded by two reverse faults

      d. a downdropped block bounded by two normal faults

 

42.  A syncline is ____________.

      a. a fold in which the strata dip away from the axis

      b. a fold with only one limb

      c. a fold in which the strata dip toward the axis

      d. a fold characterized by recumbent limbs

 

43.  The Black Hills of South Dakota are a good example of a(n) __________.

      a. anticline                         

      b. syncline                          

      c. basin                              

      d. dome

 

44.  Large circular downwarped structures are called __________.

      a. anticlines                        

      b. synclines                        

      c. basins                            

      d. domes

 

45.  Which of the following combinations should favor folding rather than faulting?

      a. high temperature and low confining pressure

      b. low confining pressure and low temperature

      c. high confining pressure and low temperature

      d. high temperature and high confining pressure

 

46.  Tensional forces normally cause which one of the following?

      a. strike-slip faults              

      b. reverse faults                 

      c. normal faults                  

      d. thrust faults

 

47.  The ____________ in California is the boundary between the North American and Pacific plates.

      a. Sierra Nevada frontal fault                                  

      b. San Andreas strike-slip fault

      c. San Luis Obispo thrust fault                                 

      d. San Francisco normal fault

 

48.  A(n) ____________ is a thick accumulation of sediments and small, tectonic blocks formed of material scraped off a descending, lithospheric plate.

      a. mass movement complex

      b. continental shelf, terrain complex

      c. accretionary-wedge complex                               

      d. subterranean-accumulation complex

 

49.  The Sierra Nevada, CA, and Teton, WY ranges are examples of ____________.

      a. fault blocks uplifted by late Tertiary to Quaternary normal faulting

      b. folding, compression, and thickening of Paleozoic strata in Jurassic time

      c. isostatic uplift of crust over thickened in early Paleozoic time

      d. uplifted blocks bounded by Quaternary reverse faults

 

 

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.

 

50.        a. p-wave                     b. s-wave                      c. surface wave            d. body wave

 

51.        a. focus                        b. seismograph              c. epicenter                   d. fault

 

52.        a. tsunami                     b. fire                           c. liquefaction                d. seiches

 

53.        a. dome                        b. anticline                    c. thrust fault                 d. basin

 

54.        a. normal fault               b. reverse fault              c. thrust fault                 d. strike-slip fault

 

Answers

  1. a

  2. c

  3. c

  4. a

  5. d

  6. d

  7. c

  8. a

  9. d

10. c

11. a

12. a

13. a

14. c

15. d

16. b

17. c

18. d

19. d

20. c

21. b

22. b

23. b

24. c

25. c

26. c

27. b

28. b

29. a

30. c

31. b

32. c

33. c

34. b

35. c

36. c

37. c

38. a

39. c

40. b

41. a

42. c

43. d

44. c

45. d

46. c

47. b

48. c

49. a

50. c

51. b

52. b

53. c

54. d