Chapter 7 Multiple Choice

 

  1. In 1980, _____________ was the first Cascade Range volcano to erupt since Mt. Lassen in 1915-16.

a. Mt. Rainier                           

b. Mt. Shasta                           

c. Kilauea                                            

d. Mt. St. Helens

 

  2. Which type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface?

a. aa                                                    

b. pegmatitic                            

c. pahoehoe                                         

d. scoria

 

  3. ____________ is a major dissolved volatile constituent in both magmas and volcanic gases?

a. Water                                              

b. Carbon monoxide      

c. Hydrogen chloride    

d. Methane

 

  4. Volcanic bombs originate ____________.

a. as laser-guided, granite blocks launched from a supersonic jet

b. as blocks of volcanic rock ejected from an erupting volcanic crater

c. as erupted magma blobs that partly congeal before falling to the ground

d. as ash particles that join together in the eruptive plume and fall as cobble-sized objects

 

  5.  ____________ magma is the most abundant type of erupted at oceanic spreading centers.

a. Basaltic                                            

b. Granitic                                            

c. Andesitic                                          

d. Pegmatitic

 

  6. The 1991 Pinatubo eruption in the Philippines caused brilliantly colored sunrises and sunsets to be seen for the next few years. What caused this phenomenon?

a. the eruption added large amounts of carbon dioxide to the atmosphere

b. the eruptive cloud destroyed parts of the Earth's protective ozone layer

c. radioactive atoms blown into the atmosphere glowed red as they decayed

d. sulfur dioxide and other erupted gases formed aerosols in the stratosphere

 

  7.  The ___________ ocean basin is rimmed by the most subduction zones.

a. Atlantic                                            

b. Indian                                              

c. Pacific                                             

d. Arctic

 

8.  Which of the following factors help determine whether a volcanic eruption will be violent or    relatively quiescent?

a. amount of dissolved gas in the magma                        

b. temperature of the magma

            c. composition of the magma                             

            d. all of these

 

  9.  Which of the following is associated with deep mantle hot spots?

a. Vesuvius and the other volcanoes of Italy

b. the volcanoes of Hawaii and Yellowstone National Park

c. the very young cinder cones scattered across the southwestern United States

d. Mt. St. Helens and other volcanoes of the Cascade Mountains

 

10.  Cinder cones __________.

a. have very steep slopes                                                                      

b. are usually less than 300 meters (1000 feet) high

c. consist largely of pyroclastics                                                

d. all of these

 

11.  The most violent volcanic activity is associated with __________.

a. fissure eruptions                   

b. shield volcanoes                    

c. cinder cones                         

d. composite cones

 

12.  The Columbia Plateau in the northwestern United States is an excellent example of __________.

            a. silica-rich lava flows                                                                         

b. pyroclastic flow deposits

            c. flood basalts                                                                                                 

d. an eroded shield volcano

 

13.   Kilauea is an example of a __________.

a. shield volcano                       

b. cinder cone                          

c. lava dome                            

d. volcanic neck

 

14.  ____________ are usually the most abundant gases emitted during basaltic volcanism.

a. Chlorine and sodium                                                                          

b. Neon and ammonia

c. Oxygen and nitrogen                                                                         

d. Water and carbon dioxide

 

15.  Paricutin is an example of a __________.

a. shield volcano                       

b. cinder cone                          

c. lava dome                            

d. composite volcano

 

16.  Mount Pelée on Martinique is an example of a __________.

a. shield volcano                       

b. cinder cone                          

c. lava dome                            

d. composite volcano

 

17.  Which statement about the May, 1980, eruption of Mount St. Helens is false?

a. during the eruptive period, the mountain peak was substantially built up by new  lavaflows and pyroclastic debris

b. plumes of ash rose high into the atmosphere during the major eruptive events

c. mudflows accompanied the major eruptive events

d. the most powerful explosive event was preceded by a massive landslide

 

18.  ____________ tend to increase the explosive potential of a magma body beneath a volcano.

a. High viscosity and dissolved gas                                            

b. High viscosity; low dissolved gas content

c. Low silica content, low viscosity                                            

d. Low viscosity; low dissolved gas content

 

19.  Which type of basaltic lava flow has its surface covered with sharp-edged, angular blocks and rubble?

a. scoria                                               

b. pahoehoe                                         

c. pillow lava                            

d. aa

 

20.  Which one of the following statements concerning volcanic blocks and bombs is true?

a. blocks are broken fragments of solid rocks; bombs have smaller sizes than lapilli

b. bombs are guided to Earth by laser beams; blocks fall anywhere

c. bombs are ejected as magma lumps; blocks are ejected as solid fragments

d. bombs and blocks are both smaller than lapilli and cinders

 

21.  ____________ destroyed the city of St. Pierre, Martinique in 1902.

a. Mudflows                             

b. Basaltic lava flows    

c. Heavy ashfall                                   

d. A nueé ardente

 

22.  Which one of the following statements concerning cinder cones is false?

a. they are small volcanoes with fairly steep sides

b. they are built mostly or entirely during one eruptive cycle

c. the cinders and other pyroclastic particles are consolidated into welded tuff

d. the cinders most commonly are basaltic

 

23.  Spreading center volcanism most generally produces rocks which are __________.

a. granitic in composition                                                                       

b. basaltic in composition

c. andesitic in composition                                                                     

d. ultramafic in composition

 

24.  Which kind of eruptive activity is most likely to be highly explosive?

a. lava flows from a large shield volcano on an oceanic island

b. fissure eruptions feeding lava to flood basalt accumulations

c. eruptions of big, continental margin, composite cones volcanoes

d. lava flows from a large cinder cone complex

 

25.  Magma tends to rise toward Earth's surface principally because

a. water is an abundant constituent of magma

b. silica is abundant in magma

c. magma is a fluid

d. rocks become less dense when they melt

 

26.  Which kind of volcanism is typical of mid-oceanic ridge systems?

a. explosive; composite cones                                                    

b. submarine; basaltic lava flows

c. fissure eruptions; flood basalts fields                          

d. explosive; rhyolitic, pyroclastic flows

 

27.  Kilauea and Mauna Loa are ____________.

a. explosive, rhyolitic volcanoes                                                 

b. andesitic composite cones

c. basaltic shield volcanoes                                                                    

d. small, basaltic cinder cones

 

28.  Mount St. Helens is ____________.

a. a basaltic cinder cone                                                                        

b. an explosive composite cone

c. a basaltic shield volcano                                                                    

d. a small, welded tuff cone

 

29.  The 1943 eruption of Paricutin in Mexico was characterized by ____________.

a. mudflows and explosive ash eruptions                        

b. welded-tuff deposition and caldera formation

c. cinder cone building and basaltic lava                         

d. pyroclastic eruptions and nueé ardente flows

 

30. The average composition of rocks comprising a large composite cone or stratovolcano is similar to a (an) ____________magma.

a. basaltic                                            

b. ultramafic                             

c. andesitic                                           

d. rhyolitic

 

31.  A ______ volcano is a very large, gently sloping mound composed mainly of basaltic lava flows.

a. composite                             

b. stratospheric                         

c. cinder cone                          

d. shield

 

32.  Which of the following best describes Shiprock, a famous volcanic feature in New Mexico?

a. a very recently active, basaltic cinder cone

b. an extinct, highly symmetrical, composite volcanic cone

c. the eroded remains of a volcanic pipe and radiating dikes

d. an extinct, massive, rhyolitic shield volcano

 

33.  Which region has the greatest concentration of currently active volcanoes?

a. the coastal plain of western Africa                                         

b. European Russia and Siberia

c. the area surrounding the Red Sea                                          

d. the circum-Pacific area

 

34.  The recent (geologically) volcanic activity in Yellowstone National Park is ____________.

a. related to plate subduction                                                     

b. related to a divergent plate boundary

c. related to a transform plate boundary                         

d. related to intraplate, hot spot volcanism

 

35.  The Icelandic volcanoes are related to plate tectonics because ____________.

a. they lie on a spreading center where two plates are converging

b. they lie on a subduction zone where two plates are converging

c. they lie on a spreading center where two plates are moving apart

d. they lie along a subduction zone where two plates are diverging

 

36.  Which one of the following best describes volcanism in the Cascade Range, northwestern U. S.?

a. related to a mantle hot spot                                                    

b. related to plate subduction

c. related to a mid-oceanic ridge system                         

d. related to deep, transform faults

 

37.  Which of the following statements best describes the big Hawaiian volcanoes?

a. lie directly above a transform plate boundary that cuts deeply into the mantle

b. lie directly above an active subduction zone where the Pacific plate is sinking into the mantle

c. lie along the crest of the East Pacific Rise, a mid-ocean ridge or spreading center

d. are situated in the interior of a large, Pacific plate above a hot spot deep in the mantle

 

38.  Which of the following is NOT considered pyroclastic debris?

a. ash                                                  

b. cinders                                             

c. bombs                                              

d. pahoehoe

 

39.  What volcanic events formed Crater Lake, OR? When did they take place?

a. a powerful explosion blew away the top of a stratovolcano; 10 million years ago

b. the crater of a large, extinct cinder cone filled with water; 5 million years ago

c. landslides and volcanic mudflows dammed the Mazama River; 500 years ago

d. caldera collapse followed major ash and pyroclastic-flow eruptions; 6000 years ago

 

40.  Which one of the following shows the correct order (left to right) of decreasing magma viscosity?

a. granite, andesite, basalt                                                                     

b. andesite, granite, basalt

c. basalt, granite, andesite                                                                     

d. basalt, andesite, granite

 

41.  The largest igneous intrusive body is called a(n) _________.

a. batholith                                           

b. laccolith                                           

c. stock                                                

d. dike

 

42.  What is the largest, known volcano in the Solar System?

a. Mauna Loa, Hawaii, Earth                                                    

b. Mount Olympus, Greece, Earth

c. Mauna Kea, southern hemisphere, Mars                    

d. Olympus Mons, Mars

 

43.  A ____________ is the largest, discordant body of intrusive, igneous rock.

a. lopolith                                             

b. laccolith                                           

c. pluton                                               

d. batholith

 

44.  A ____________ is an intrusive, igneous rock body that is tabular and concordant.

a. laccolith                                           

b. dike                                                 

c. pluton                                               

d. sill

 

45.  A ____________ is a near surface, intrusive, igneous rock body that results from local inflation of a horizontal sill.

a. batholith                                           

b. dike                                                 

c. laccolith                                           

d. volcanic neck

 

46.  Which of the following best describes the bedrock in the Sierra Nevada Mountains in California?

a. basalt; dikes                                                                                                 

b. gabbro; plutoliths

c. andesite; laccoliths                                                                            

d. granite; batholiths

 

47.  Most of the active volcanoes on Earth are located in a belt known as the __________.

a. Ring of Fire                                                                                                  

b. Gulf Coast Zone

c. Mid-Pacific Ridge                                                                             

d. Red Sea rift

 

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.

 

48.        a. silica content             b. temperature               c. dissolved gases          d. pressure

 

49.        a. pahoehoe                  b. aa                             c. volcanic bomb           d. pillow lava

 

50.        a. ash                           b. crystals                     c. lapilli                         d. blocks

 

51.        a. caldera                      b. pipe                          c. crater                        d. fumarole

 

52.        a. Mt. Vesuvius             b. Mt. Mazama             c. Mount Pelée              d. Kilauea

 

53.        a. sill                             b. batholith                    c. dike                          d. laccolith

 

Answers

  1. d

  2. c

  3. a

  4. c

  5. a

  6. d

  7. c

  8. d

  9. b

10. d

11. d

12. c

13. a

14. d

15. b

16. d

17. a

18. a

19. d

20. c

21. d

22. c

23. b

24. c

25. d

26. b

27. c

28. b

29. c

30. c

31. d

32. c

33. d

34. d

35. c

36. b

37. d

38. d

39. d

40. a

41. a

42. d

43. d

44. d

45. c

46. d

47. a

48. d

49. c

50. b

51. b

52. d

53. b