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Name Class Date
Skills Worksheet
Directed Reading A
Section: Volcanic Eruptions
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?
NONEXPLOSIVE ERUPTIONS
______ 5. Which of the following can happen during nonexplosive eruptions?
violent explosions
tons of rock blasted into the
air
huge lava flows
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.
EXPLOSIVE ERUPTIONS
____ 9. Which of the following would you expect to see during an
explosive volcanic eruption?
calm lava flows
hot debris, ash, and gas shooting into the
air
a rainbow
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?
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Name Class Date
Directed Reading A continued
WHAT IS INSIDE A VOLCANO? Match the correct definition with the correct
term. Write the letter in the space
provided.
______13. hot liquid material below the Earth’s
surface ______14. an opening in the Earth’s crust
a. vent b. magma
c. lava
______15. molten material flowing on the Earth’s
surface
WHAT MAKES UP MAGMA?
______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.
the
17. The more water contained in the magma, the
chances an explosive eruption will occur.
WHAT ERUPTS FROM A VOLCANO?
18. The main product of a nonexplosive eruption is
.
19. The main product of an explosive eruption is
.
is blasted into the
20. Pyroclastic material forms when air and hardens.
Match the correct description with the correct term. Write the letter in the space
provided.
______21. forms underwater in rounded lumps a. aa lava
______22. flows slowly, like dripping
wax
______23. has a brittle, jagged crust
b. pillow
lava
c. pahoehoe
lava
d. blocky lava ______24. cool,
stiff lava that forms jumbled heaps
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Name Class Date
Directed Reading A continued
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.
Match the correct description with the correct term. Write the letter in the space
provided.
______28. large blobs of magma that harden in the air a. volcanic blocks
______29. solid rock blasted out of a
volcano
______30. glass-like slivers from the walls of
exploding
gas bubbles ______31. pebblelike bits of magma that
b. volcanic bombs
c.
lapilli
d.
volcanic
ash
cool in the air
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 .
Copyright © by Holt, Rinehart and Winston. All rights reserved.