Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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Most of the
rock in Yosemite National Park is an exposed ____. a. | dike | c. | batholith | b. | sill | d. | volcanic rock | | | | |
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2.
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Soufriére Hills volcano, in Montserrat, is a ____ volcano. a. | cinder
cone | c. | composite | b. | hot spot | d. | shield | | | | |
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3.
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The
steep-walled depression around a volcano's vent is a ____. a. | caldera | c. | dike | b. | crater | d. | volcanic rock | | | | |
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4.
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Differences
in ____ cause a volcanic neck to form. a. | water content | c. | resistance to erosion | b. | eruptive
forces | d. | silica
content | | | | |
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5.
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Magma that
is squeezed into a generally vertical crack that cuts across rock layers and hardens is called a
____. a. | sill | c. | volcanic
neck | b. | batholith | d. | dike | | | | |
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6.
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In 1990,
lava from ____ covered most of a town in Hawaii. a. | Mount St. Helens | c. | Mount Pelée | b. | Mount
Pinatubo | d. | Kilauea | | | | |
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7.
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If, after an
eruption, the top of a volcano collapses down, a ____ forms. a. | vent | c. | volcanic
neck | b. | crater | d. | caldera | | | | |
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8.
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Some
volcanoes form islands as ____ flows from rifts in the seafloor and builds up high enough to break
the ocean's surface. a. | water | c. | tephra | b. | lava | d. | gas | | | | |
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9.
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More than
____ of Earth's volcanoes are currently active.
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10.
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A batholith
is created when ____. a. | lava forms a thick sheet | b. | magma in a sill pushes
up to form a rock dome | c. | magma cools underground before reaching the
surface | d. | lava fills a vent | | |
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11.
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Sills are
formed when ____. a. | magma enters a vertical
crack between rock layers and hardens | b. | the top of a volcano collapses down | c. | magma flows onto the
surface | d. | magma is squeezed into a horizontal crack between rock layers and
hardens | | |
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12.
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A ____ often
forms a mountain when layers of lava and volcanic ash erupt and build up. a. | batholith | c. | volcano | b. | dike | d. | caldera | | | | |
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13.
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The 1995
eruption of the Soufriére Hills volcano in Montserrat resulted in ____. a. | ash | c. | acid
rain | b. | heat | d. | all of the
above | | | | |
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14.
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The
Soufriére Hills volcano is an example of a ____volcano. a. | composite | c. | shield | b. | Hawaiian | d. | cinder cone | | | | |
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15.
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Kilauea in
Hawaii is the world's most ____ volcano. a. | dormant | c. | explosive | b. | active | d. | all of the above | | | | |
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16.
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Dikes are
formed when ____. a. | the top of a volcano
collapses down | b. | magma heats water | c. | magma enters a
horizontal crack between rock layers and hardens | d. | magma enters a vertical
crack between rock layers and hardens | | |
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17.
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Magma that
squeezes into a horizontal crack between rock layers and hardens is called a ____. a. | batholith | c. | volcanic
neck | b. | sill | d. | dike | | | | |
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18.
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Paricutin,
in Mexico, is a ____ volcano. a. | composite | c. | hot spot | b. | cinder cone | d. | shield | | | | |
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19.
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Basaltic
magma produces nonexplosive eruptions such as those at ____. a. | Mount St.
Helens | c. | Mount
Unzen | b. | Mount Pinatubo | d. | Kilauea | | | | |
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20.
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Devil's
Tower in Wyoming is an example of a ____. a. | volcanic neck | c. | dike | b. | caldera | d. | batholith | | | | |
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21.
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Magma forms
deep inside Earth because of ____. a. | a rise in temperature | c. | an increase in pressure | b. | a drop in
pressure | d. | both a and
b | | | | |
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22.
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Silica-rich
magma ____. a. | sometimes forms where
Earth's plates are coming together and one plate is forced under another | b. | produces explosive
eruptions | c. | is thick and gas gets trapped, causing pressure to build
up | d. | all of the
above | | |
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23.
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One factor
that determines whether a volcanic eruption will be quiet or explosive is ____. a. | the amount of water
vapor and other gases trapped in the magma | b. | the number of cinder cones | c. | the amount of tephra in
the magma | d. | the height of the volcano's vent | | |
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Matching
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Match
each statement with the correct item below. a. | caldera | d. | composite volcano | b. | batholith | e. | cinder cone
volcano | c. | volcanic neck | f. | shield volcano | | | | |
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24.
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Devil's
Tower, Wyoming—hard magma core
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25.
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Yosemite
National Park granite domes in California—exposed at Earth's surface by erosion
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26.
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Kilauea,
Hawaii—quiet lava flows
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27.
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Crater Lake
in Oregon—the top of a volcano collapsed down
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28.
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Paricutin,
Mexico—pile of ash and cinders
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29.
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Soufriére Hills volcano—one plate was forced beneath another
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Completion
Complete each sentence or
statement.
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Figure 12-1
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30.
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Figure 12-1B
is a(n) ________________________________________. It is made of
________________________________________.
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31.
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Figure 12-1C
is a(n) ______________________________. It is made of
________________________________________.
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32.
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Figure 12-1A
is a(n) ______________________________. It is made of
________________________________________.
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33.
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Magma is
____________________ dense than the rock around it, so it is forced ____________________ Earth's
surface.
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34.
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Ash, lava,
and ____________________ erupt from the crater of a volcano.
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35.
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Two
important factors that control whether an eruption will be explosive or quiet are the amount of
_________________________ and other gases and the amount of ____________________ in the
magma.
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36.
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Over time,
magma reaches Earth's surface and flows out through an opening called a(n) ____________________. As
lava flows out, it cools quickly and becomes solid, forming layers of ____________________ rock
around the opening.
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Short Answer
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37.
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How do the
Hawaiian Islands differ from the Soufriére Hills volcano?
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38.
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How are a
soft-drink container and magma alike?
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39.
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Compare and
contrast silica-poor and silica-rich magma.
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40.
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If lava from
volcanoes moves slowly enough that people can get away from it, why are volcanoes
dangerous?
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41.
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Why do
volcanoes form at plate boundaries and hot spots?
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True/False
Indicate whether the sentence or statement is true
or false.
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42.
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A volcanic
neck forms when a volcano's core erodes.
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43.
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Volcanoes
can form on the ocean floor.
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44.
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There is no
relationship between plate tectonics and volcanoes.
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45.
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Gas trapped
in magma under high pressure can cause explosive eruptions.
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46.
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Today,
people are never killed by volcanic eruptions.
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47.
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Cinder cone
volcanoes produce quiet eruptions.
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48.
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Most igneous
activity takes place above ground in volcanoes.
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