READING QUESTIONS: Volcanism GEOL 131
NAME________________________ DUE:
th
Fall 2015
56 pts
All answers should be in your own words.
1.
How are the eruptions of these two volcanoes different? (2 pts) ____________________________
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2.
Define viscosity.
(2 pts) _______________________________________________________________
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3.
How does magma viscosity influence the explosiveness of a volcanic eruption? (2 pts)
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4.
What is the role of gases in explosive volcanic eruptions? (2 pts)
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5.
What type of magmas can produce eruption columns ? ___________________________________
6.
Describe pahoehoe and aa lava flows. (4 pts) _________________________________________
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7.
What is the most abundant gas in most magmas? _______________________________________

8.
What is the difference between a volcanic bomb and a block , both in terms of their physical shape and how they form? (3 pts)
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9.
What is the difference between volcanic ash and lapilli ? (2 pts) ___________________________
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10.
How is a crater different from a caldera? (2 pts) ________________________________________
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11.
Match each term below with the correct definition. (3 pts) a.
Vent b.
Conduit a parasitic cone that emits only gases a path taken by magma through the interior of a volcano
_____
_____ c.
Fumarole an opening through which volcanic materials are ejected _____
12.
Describe the composition and viscosity of the lava associated with shield volcanoes. (2 pts)
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13.
Are pyroclastic materials significant components of shield volcanoes? _______________
14.
Do most shield volcanoes form on continents or on the ocean floor? _________________

15.
How are lava tubes related to the large extent of the lava flows associated with shield volcanoes? (2 pts)
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16.
EXTRA CREDIT: (3 pts) Name up to three shield volcanoes not located in the United States.
_____________________________________________________________________________ a.
____________________________________ b.
____________________________________ c.
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17.
Describe the composition of cinder cones. (2 pts) _________________________________________
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18.
Is a typical cinder cone (steeper / less steep) than a shield volcano? Is it (taller / shorter) than a shield volcano? (Circle one answer in parentheses.)
19.
Over what time frame does a typical cinder cone form? __________________________________
20.
EXTRA CREDIT: It took the Mexican cinder cone Paricutin 5 days to reach a height of 330 feet, beginning at a height of 0 feet the first day it began erupting. Calculate Paricutin’s daily rate of growth over these 5 days, in feet/day, using this data. Show all work in a legible and orderly fashion. (3 pts)
Daily rate of growth: _________________
21.
What zone on Earth has the greatest concentration of composite volcanoes? ____________________
22.
What do composite volcanoes consist of? (2 pts) ________ __________________________________
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23.
How do the composition and viscosity of lavas associated with composite cones and shield volcanoes differ?(2 pts) ______________________________________________________________________
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24.
Describe pyroclastic flows. Why can they travel very long distances? (3 pts) ____________________
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25.
What is a lahar? (2 pts) _______________________________________________________________
26.
List three volcanic hazards other than pyroclastic flows and lahars. (3 pts) a.
____________________________________________________________________________ b.
____________________________________________________________________________ c.
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27.
Give a brief description of the formation of Crater Lake. (3 pts) ______________________________
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28.
How is the lava from a fissure eruption different from that associated with composite volcanoes? (2 pts)
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29.
What kind of structure is Shiprock, New Mexico and how did it form? (3 pts)
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30.
Are volcanoes in the Ring of Fire generally explosive or quiescent? Name one example that supports your answer. (2 pts) ___________________________________________________________________
31.
Which type of plate boundary produces the majority of Earth’s annual magma output?
__________________
32.
Name one geographic example, besides the Hawaiian Islands, of a volcanic structure produced by intraplate volcanism. _______________________
33.
EXTRA CREDIT: Choose one volcano shown on Figure 28, and research the following information about it. You can use any source you like. A good place to start is the US Geological Survey’s volcano information website at http://volcanoes.usgs.gov/about/volcanoes/volcanolist.php
. This lists only United
States volcanoes. For others, Oregon State’s volcano website is a good place to look: http://volcano.oregonstate.edu/oldroot/volcanoes/alpha.html
. (4 pts)
Volcano name: _______________________
Location (give country name, ocean name, etc.): ________________________
Elevation (in feet or meters): _____________________
Last known eruption date: ______________________