CHAPTER 13 VOLCANOES
Name ______________________ Period _____
CHAPTER 13; VOLCANOES; SECTION 1; VOLCANOES AND PLATE TECTONICS; PAGE 318
1. Describe 3 conditions that produce magma under the Earth’s surface.
i._____________________________________________________________________________________________
ii. ____________________________________________________________________________________________
iii.____________________________________________________________________________________________
2. Study the graph on page 319. How does pressure relate to the Earth’s depth? ____________________________________
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3. What is the pressure of the Earth at 5,000 km? ____________________________________________________________
4. How does temperature relate to the Earth’s depth? _________________________________________________________
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5. What is the temperature below the Earth’s surface at 1000 km? _______________________________________________
6. Magma rises through the Earth’s surface because it is less dense than the surrounding rock. Explain two ways in which
magma increases in size as it moves towards Earth’s surface.
i._____________________________________________________________________________________________
ii. ____________________________________________________________________________________________
7. Using the words lava, vents, and cone, describe how a volcano forms. __________________________________________
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8. Look at Figure 2 on page 320. What is the relationship between the volcanoes and tectonic plate boundaries? _________
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9. What two types of boundaries are responsible for most of the volcanoes in the world? ______________________________
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10. Besides volcanoes, what other natural force occurs in the Pacific Ring of Fire? __________________________________
11. When a plate that consists of oceanic crust and one that consists of continental crust meet, which plate subducts beneath
the other plate? _______________________________________________________________________________________
12. Look at Figure 3 on page 321. What surface feature occurs when two oceanic plates converge? ____________________
13. How are trenches and volcanoes related? _______________________________________________________________
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14. Compare and contrast the Aleutian Islands and Japan. _____________________________________________________
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15. Where does the most magma reach the ocean’s surface? ___________________________________________________
16. Explain what happens as magma comes to the surface where plates move apart at mid-ocean ridges? _______________
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17. Why don’t humans notice most volcanic eruptions that take place along mid-ocean ridges? ________________________
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18. Look at Figure 4 on page 322. How does pillow lava form? _________________________________________________
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19. Look at Figure 5 on page 323. Describe how the Hawaiian Islands formed. _____________________________________
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For questions 20 - 23: Use the numbers 1 through 4 to show the sequence of volcano development in a hot spot; 1 being the
beginning of development, 4 being the end of development.
20. ____ Volcanoes form in the interior of a tectonic plate.
21. ____ Columns of solid, hot material called mantle plumes rise and reach the lithosphere.
22. ____ Magma rises to the surface and breaks through the overlying crust.
23. ____ A mantle plume reaches the lithosphere, and spreads out.
24. Which Hawaiian Island is currently active (spews lava)? ____________________________________________________
25. Why are the other Hawaiian Islands “extinct”? ____________________________________________________________
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26. Look at Figure 6 on page 324. How did the Devil’s Tower (volcanic neck) form in Wyoming? _______________________
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CHAPTER 13; VOLCANOES; SECTION 2; VOLCANIC ERUPTIONS; PAGE 325
27. Lava provides an opportunity for scientists to study which two layers of the Earth?
i.___________________
ii. __________________
28. Why would it make sense that volcanoes are one of the only ways that scientists can study the Earth’s interior (THINK…the
answer is not spelled out in your book!!)? ___________________________________________________________________
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29. Below is a list of characteristics that apply to mafic magma, felsic magma, or both mafic and felsic magma. Next to each
characteristic, label if the magma is MAFIC, FELSIC, or BOTH. Write the word, do not abbreviate.
__________ Magma associated with explosive eruptions
__________ Magma that produces runny lava
__________ Magma that is light colored
__________ Magma rich in iron and magnesium
__________ Magma that is dark colored
__________ Magma that produces sticky lava
__________ Magma with high viscosity
__________ Magma composed of silicate materials
__________ Magma that makes up continental crust
__________ Magma that makes up oceanic crust
__________ Magma associated with quiet eruptions
__________ Magma with low viscosity
30. Read “Math Practice” on page 326. What type of magma is erupting from Mt. Kilauea? _________ Given the information
in that section, calculate the average amount of lava, in cubic meters that erupts from Kilauea each year. _________________
31. What are three characteristics of Pahoehoe?
i._____________________________________________________________________________________________
ii. ____________________________________________________________________________________________
iii._____________________________________________________________________________________________
32. Aa forms from the same composition as Pahoehoe. However, Aa has a very different texture. What three differences
produce this texture?
i._____________________________________________________________________________________________
ii. ____________________________________________________________________________________________
iii.____________________________________________________________________________________________
33. Blocky lava has more ____________ than Aa. This makes blocky lava more ________________ than Aa. Due to this,
blocky lava forms _______________ _______________ ___________ when it cools (Use Figure 2 on 326).
34. Pahoehoe, Aa, and blocky are all what types of ____________ lava.
35. What state is Mount St. Helens in? (don’t know? consult an Atlas!)
__________________________________________
36. Why is it dangerous to have large amounts of trapped gases in lava? __________________________________________
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37. What is pyroclastic material? _________________________________________________________________________
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38. Scientists classify pyroclastic materials by:
a. their shape and composition.
b. their size.
c. their location relative to the volcano.
d. the amount of time they take to cool.
39. Number the following types of pyroclastic materials from largest in size to smallest in size.
_____Volcanic bomb
_____Volcanic ash
_____Lapilli
_____Volcanic blocks
_____Volcanic dust
TYPES OF VOLCANOES; PAGE 328
40. Volcanoes are scientifically called volcanic _____________ and are broken up into three main types.
Match the type of volcano, or volcanic feature, with the appropriate letter.
41. _____ Volcanic cone
A. Volcanic cone that is broad at the base and has gently sloping sides
42. _____ Crater
B. Structure formed by lava and pyroclastic material ejected during eruptions
43. _____ Shield volcano
C. Volcano with steep slopes; rarely more than a few hundred meters high
44. _____ Cinder cone
D. Volcano made of alternating layers of hardened lava and pyroclastics
45. _____ Composite volcano
E. Funnel shaped pit at the top of a volcanic vent
46. In the boxes below, draw a small picture of each type of volcano.
Shield Volcano
Cinder Cone
Composite Volcano
CALDERAS; PAGE 329
47. What is a caldera? _________________________________________________________________________________
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48. What are the three steps that most often occur in the formation of a caldera?
i._____________________________________________________________________________________________
ii. ____________________________________________________________________________________________
iii.____________________________________________________________________________________________
PREDICTING VOLCANIC ERUPTIONS; PAGE 330
49. One of the most important warning signals of volcanic eruptions is:
a. A change in earthquake activity around the volcano
b. A change in air pressure around the volcano
c. A change in animal behavior around the volcano
d. Increases steepness of the volcanic cone.
50. What are three causes of small earthquakes that could signal a volcanic eruption?
i._____________________________________________________________________________________
ii. ____________________________________________________________________________________
iii.____________________________________________________________________________________
51. What are two problems scientists face in using a volcano’s past behavior to predict a future eruption?
i._____________________________________________________________________________________
ii. ____________________________________________________________________________________
52. Imagine you live in a region that is troubled with earthquakes. If scientists had the methods and the means to warn you
three minutes before a large earthquake was about to take place, would you want to know, yes or no? Why or why not?
_____________________________________________________________________________________________________
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Same situation but the scientists now can warn you one day before a MASSIVE earthquake. Would you want to know; yes or
no? Why or why not? __________________________________________________________________________________
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