Chapter 6; Section 1: Pages 156-161
1. What is the name of the molten rock inside a volcano?
a. Pressure c. Magma
b. Ash d. Lava
2. What is magma that flows onto the Earth’s surface called?
a. Lava c. Magma
b. Ash d. Rock
3. 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
4. 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
5. 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
6. What is ash?
a. Flowing lava c. Big chunks of rock
b. Tiny, dust-sized rock d. A gas
7. What is a vent?
a. A magma chamber c. A crack in the crust
b. An eruption d. Underground volcano
8. 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
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
13. Forms underwater in rounded lumps
14. Flows slowly, like dripping wax
15. Has a brittle, jagged crust
16. Cool, stiff lava that forms jumbled heaps
17. Large blobs of magma that harden in the air
18. Solid rock blasted out of a volcano
19. Glass-like slivers from exploding gas bubbles
20. Pebble like bits of magma that cool in the air
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 ______.
Chapter 6; Section 2: Pages 162-165
1. 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
2. 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
3. Formed from layers of lava;
can be quite large
4. Formed from layers of lava
and pyroclastic material
5. Made entirely of pyroclastic
materials
6. 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.
Chapter 6; Section 3: Pages 166-171
1. 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
2. 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
3. What causes magma to form?
a. Puttylike rock
b. Changes in temperature and pressure
c. Atoms of the mantle
d. Low temperatures
4. 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
5. 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
6. 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
7. 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
8. 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
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
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
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