Download Volcanoes Directed Readings

Name: _______________________________________________________ Date: ____________ Period: _____________
Chapter 6; Section 1: Pages 156-161
1.
Volcanic eruptions can be ____________ times stronger than the
explosion produced by the first atomic bomb.
2. What is magma?
3. Magma that flows onto the Earth’s surface is called
______________.
4. What is a volcano?
5. 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
6. The most common type of volcanic eruption is _____________.
7. Large areas of the Earth are covered with ______________ from
nonexplosive eruptions,
8. Volcanic eruptions occur on land and on the _____________floor.
9. Which of the following would you expect to see 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
10. In a volcanic eruption, molten rock is blown into dust-sized
particles called _________________.
11. How quickly can an explosive eruption demolish a mountainside?
12. During an explosive eruption, where do larger pieces of debris
fall?
13. Hot liquid material below the surface
14. An opening in the Earth’s crust
15. Molten material flowing on the surface
a. Vent
b. Magma
c. Lava
16. Silica-rich magma
a. Has a thin, runny consistency
b. Allows gases to escape easily
c. Causes explosive eruptions
d. Is rarely associated with explosive eruptions
17. The more water contained in magma, the _________ the chances
an explosive eruption will occur.
18. The main product of a nonexplosive eruption is ___________.
19. The main product of an explosive eruption is _______________.
20. Pyroclastic material forms when ___________ is blasted into the
air and hardens.
a. Aa lava
21. Forms underwater in rounded lumps
b. Pillow lava
22. Flows slowly, like dripping wax
c. Pahoehoe lava
23. Has a brittle, jagged crust
d. Blocky lava
24. Cool, stiff lava that forms jumbled heaps
25. The viscosity of lava tells how ___________ the lava is.
26. Lava that pours out quickly and forms a brittle crust is called
______________ lava.
27. Lava that flows slowly and has rounded wrinkles on its glassy
surface is called ______________ lava.
28. Large blobs of magma that harden
in the air
29. Solid rock blasted out of a volcano
30. Glass-like slivers from the walls of
exploding gas bubbles
31. Pebble like bits of magma that cool
in the air
a. Volcanic blocks
b. Volcanic Bombs
c. Lapilli
d. Volcanic ash
32. When large amounts of hot ash, dust and gases are ejected from a
volcano, the result is a dangerous type of flow called a(n)
________________.
33. Pyroclastic materials can race downhill at speeds of more than
_______________.
14. When the roof over a magma chamber collapses, it
forms a
a. Vent
b. Caldera
c. Crater
d. Lava plateau
15. Craters, calderas, and lava plateaus are volcanic
____________.
16. A caldera is __________ than a crater.
17. A long crack in the Earth’s crust is called
18. After repeated eruptions of lava spread over a large
area, ___________ is formed.
19. Lava plateaus are created by _____________ eruptions.
Chapter 6; Section 2: Pages 162-165
Place the following events in order to show how a single volcano can cause
widespread disaster.
1. _________Less sunlight reaches Earth
2. _________There is a large-scale volcanic eruption
3. _________The Earth experiences longer, harsher
winters and wetter, milder summers
4. _________The average global temperature drops
5. _________Worldwide food shortages occur because of
widespread crop failures.
6. _________Volcanic ash and sulfur-rich gases spread
through the atmosphere
7. The largest mountains on
a. Shield volcano
Earth
b. Cinder Volcano
8. Forms from lava; not steep
c. Composite
9. Often occurs in clusters
Volcano
10. Forms from alternating
layers of pyroclastic material and lava
11. Made entirely of pyroclastic materials
12. Sometimes called stratovolcano
Chapter 6; Section 3: Pages 166-171
1.
2.
13. The funnel-shaped pit around a volcano’s central vent is
a(n)
a. Magma chamber
b. Caldera
c. Crater
d. Lava plateau
3.
4.
5.
6.
2
To help predict eruptions, scientists study _________________
coming from active volcanoes and look for changes in the
volcanoes.
The rock of the Earth’s mantle
a. Flows very quickly
b. Has a puttylike consistency
c. Is cooler than the Earth’s crust
d. Is solid and rock-hard
Rock usually melts to form magma
a. When there is an increase in pressure
b. When there is a decrease in pressure
c. When there is a decrease e in temperature
d. When it is in a volcano
Magma forms in the deeper regions of the Earth’s
______________ and the uppermost layers of the _____________.
Changes in __________ and ____________ cause magma to form.
How does magma behave like air bubbles in a jar of honey?
7.
About 80% of active volcanoes on land form where plates
a. Join
b. Collide
b. Separate
d. Slide past each other
8. Tectonic plate boundaries are areas where tectonic plates
______________________, ______________________, and/or
_________________________.
9. Why are the plate boundaries surrounding the Pacific Ocean called
the Ring of Fire?
10. A set of rifts between separating plates is called a(n)
a. Divergent boundary
c. Crater column
b. Mantle rock
d. Rift zone
11. Tectonic plates separate at a(n) ________________ boundary.
Place the following in the correct order:
12. ____Magma rises to the surface of the surrounding rock.
13. ____Mantle material rises to fill the spaces between the plates.
14. ____The magma forms a new crust on the ocean floor
15. ____A rift forms as tectonic plates move apart
16. ____The mantle rock melts because of the decrease in pressure.
Match each with the correct volcano type:
24. Have not erupted in thousands of years.
25. Have not erupted recently
26. Are erupting now
27. Probably won’t erupt again
28. Will probably erupt in the future
29. Will probably erupt in the near future
a. Active
b. Dormant
c. Extinct
30. Just before an eruption, the number and intensity of small
earthquakes ___________________.
31. Changes in the ratio of sulfur dioxide to carbon dioxide may
indicate changes in the _____________ below.
32. Small changes in the volcanoes slope can be ________________.
33. What are 3 ways scientists can predict volcanic explosions?
34. What might cause a bulge in the slope of a volcano?
17. Subduction is
a. The movement of one tectonic plate against another
b. The movemnt of one tectonic plate over another
c. The movemnt of one tectonic plate under another
d. The novement of one tectonic plate away from another
18. Convergent boundaries commonly exist where
a. Tectonic plates move side by side
b. Oceanic crust moves away from continental crust
c. Continental crust is subducted under oceanic crust
d. Tectonic plates collide with each other
19. As the ocean crust sinks deeper into the mantle
20. The oceanic crust is _____________ and _________________
than the continental crust.
21. The Hawaiian lands are located
22. What are hot spots?
23. Some scientists believe that hot spots form along in the Earths’
crust.
3