Download Volcano Directed Reading

Name: _______________________________________________________ Date: ____________ Period: _____________
9.
What affects how explosive a volcanic eruption is?
a. Heat
c. Composition of magma
b. Amount of lava
d. Ash
10. What is most likely to happen if the water content of magma is
high?
a. A nonexplosive eruption will occur
b. No eruption will occur
c. Pressure will decrease
d. An explosive eruption is likely
11. Which of the following is true?
a. Silica-rich magma has a thin, runny consistency
b. Silica-rich magma allows gases to escape easily
c. Silica-rich magma causes explosive eruptions
d. Silica-rich magma causes nonexplosive eruptions
12. What is pyroclastic material?
a. Molten rock
b. Magma that blasts into the air and hardens
c. Lava that flows underwater
d. Magma that remains underground too long
Chapter 6; Section 1: Pages 156-161
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8.
What is the name of the molten rock inside a volcano?
a. Pressure
c. Magma
b. Ash
d. Lava
What is magma that flows onto the Earth’s surface called?
a. Lava
c. Magma
b. Ash
d. Rock
How are volcanoes created?
a. By tectonic plates colliding
b. By cracks in the Earth’s crust
c. By collections of ash and rock
d. By many eruptions of lava
Which of the following can happen during nonexplosive eruptions?
a. Violent explosions
b. Tons of rock blasted into the air
c. Huge lava flows
d. Fire shooting into the air
Which of the following can happen during an explosive volcanic
eruption?
a. Calm lava flows
b. Hot debris, ash, and gas shooting into the air
c. A rainbow
d. Lava fountains
What is ash?
a. Flowing lava
c. Big chunks of rock
b. Tiny, dust-sized rock
d. A gas
What is a vent?
a. A magma chamber
c. A crack in the crust
b. An eruption
d. Underground volcano
Where is a volcano’s magma chamber?
a. At the top of the vent
c. On the volcano’s slope
b. Deep underground
d. Outside the volcano
a.
b.
c.
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16.
Forms underwater in rounded lumps
Flows slowly, like dripping wax
Has a brittle, jagged crust
Cool, stiff lava that forms jumbled heaps
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20.
Large blobs of magma that harden in the air
Solid rock blasted out of a volcano
Glass-like slivers from exploding gas bubbles
Pebble like bits of magma that cool in the air
Pyroclastic
Temperature
d.
Aa lava
Pillow lava
Pahoehoe lava
Blocky lava
a.
b.
c.
d.
Volcanic blocks
Volcanic bombs
Lapilli
Volcanic ash
Hurricane
21. A very dangerous type of volcanic flow is a(n) ______________
flow.
22. Pyroclastic materials can move faster than a(n) ______________.
23. The center of a pyroclastic flow has a very high _____________.
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Chapter 6; Section 2: Pages 162-165
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Chapter 6; Section 3: Pages 166-171
What happens during large-scale eruptions?
a. Magma is forced deeper underground
b. Some lava escapes through the volcano’s vent
c. Enormous amounts of ash and gases are ejected into the
atmosphere
d. Blocky lava plugs the volcano’s vent
Which of these describes a climate change caused by a volcanic
eruption?
a. Temperature rises
b. Ash blocks sunlight, causing temperatures to drop
c. Burned land creates dry conditions
d. Volcanic eruptions don’t cause climate changes
Formed from layers of lava;
can be quite large
Formed from layers of lava
and pyroclastic material
Made entirely of pyroclastic
materials
Landforms
Lava plateau
Caldera
Rift
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a. Shield volcano
b. Cinder cone volcano
c. Composite volcano
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Crater
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Craters, calderas, and lava plateaus are volcanic
___________________
7. A funnel-shaped pit around a volcano’s central vent is called a(n)
_____________________.
8. When the roof over a magma chamber collapses, it forms a(n)
_______________________.
9. A long crack in the Earth’s crust is called a(n) _______________.
10. After repeated eruptions of lava spread over a large area, a(n)
_______________ is formed.
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What do scientists study to help them predict a volcanic eruption?
a. Ocean currents and temperature
b. Old volcanoes and craters
c. Vents and calderas
d. Gases and changes in a volcano’s shape
Where does magma form?
a. In the Earth’s crust and mantle
b. In the Earth’s coat and crust
c. In the Earth’s oceans and rivers
d. On the Earth’s surface
What causes magma to form?
a. Puttylike rock
b. Changes in temperature and pressure
c. Atoms of the mantle
d. Low temperatures
What is the most common cause of magma formation?
a. Increase in temperature c. Increase in pressure
b. Decrease in temperature d. Decrease in pressure
Magma is less dense than the surrounding rock, so the magma
slowly
a. Sinks
c. Rises
b. Melts into liquid rock
d. Moves to the side
Why are the plate boundaries surrounding the Pacific Ocean called
“The Ring of Fire”?
a. There is a huge lava plateau there
b. There are many active volcanoes in the area
c. There is a large ring-shaped crater there
Where do most active volcanoes form?
a. Where tectonic plates form
b. Where tectonic plates separate
c. Where tectonic plates collide
d. Where tectonic plates slide past each other
Where do tectonic plates move away from each other?
a. At rift zones
c. In the mantle rock
b. At a divergent boundary d. In the Earth’s crust
9.
What is a deep set of cracks between plates called?
a. Divergent boundary
c. Crater column
b. Mantle rock
d. Rift zone
10. Why does magma rise toe the Earth’s surface?
a. Magma is heavier than rock
b. Magma is less dense than the rock around it
c. Magma is harder than the rock around it
d. Magma is tricky
11. What is the name of a mountain chain created by lava from
undersea rift zones?
a. Divergent boundary
c. Mid-ocean ridge
b. Tectonic plate
d. Hot springs
Mantle plumes
Convergent boundary
Subduction
Temperature
21. What happens just before a volcanic eruption?
a. The number of small earthquakes increases
b. Lava fountains spew out all around the volcano
c. Gases turn to poison
d. There is a great deal of thunder and lightening
22. What can changes in volcanic gases indicate?
a. Changes in temperature
b. Changes in the magma chamber below
c. Changes in an earthquake’s intensity
d. Changes in weather
23. What is a tiltmeter?
a. An instrument that measures sound
b. An instrument that measures gases
c. An instrument that measures earthquakes
d. An instrument that measures small changes in a volcano’s
slope
Hot spot
Cracks
12. The place where tectonic plates collide is called a(n)
__________________________.
13. The movement of one tectonic plate under another is called
__________________________.
14. When oceanic crust scrapes under continental crust, the
_______________ and pressure increase.
15. A volcanically active place that is far from any plate boundary is
called a(n) ____________________________.
16. Some scientists believe that hot spots are places above
______________________________, which are columns of rising
magma.
17. Some scientists believe that hot spots form along ______________
in the Earth’s crust.
18. Probably won’t erupt again
19. Will probably erupt again
20. Will probably erupt soon
a.
b.
c.
Active
Dormant
Extinct
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