Earth Science
Name:
Chapter Nine--Worksheet Review # 1
Class Period:
Section One: [Pages 222-226]
Directions: Use your textbook and notes to assist you with answering the following questions.
1. Volcanic eruptions can be
first atomic bomb.
times stronger than the explosion produced by the
2. What is a volcano?
3. Most volcanic eruptions are
. (explosive or nonexplosive)
4. All of the following can happen during nonexplosive eruptions EXCEPT
.
a. lava flows.
b. tons of rock are blasted into the air.
c. lava forms fountains.
d. rivers of red-hot lava form.
5. Which of the following would you expect to see during an explosive volcanic eruption? (May have more than
one answer.)
a. pieces of molten rock hardening in the air
b. huge lava flows
c. hot debris and gases moving at supersonic speeds d. a powerful explosion
6. Look at Figure 2 on page 223. When Mount St. Helen's erupted in 1980, how
many square kilometers of forest were damaged?
Match each volcanic feature in Column B with the correct description in Column A, and write the corresponding
letter in the appropriate space.
COLUMN A
COLUMN B
7. hot liquid material below the Earth’s surface
8. a combination of a vent and a buildup of lava or pyroclastic material
on the Earth’s surface
a. vent
b. lava
c. magma
9. a hole or crack in the Earth’s crust
d. volcano
10. molten material flowing on the Earth’s surface
11. The more
will occur.
contained in the magma, the greater the chances a violent eruption
12. Silica-rich magma
.
a. has a thin, runny consistency.
c. causes explosive eruptions.
b. allows gases to easily escape.
d. is rarely associated with explosive volcanoes.
13. 13 is the main product of a nonexplosive eruption, while the main product of
an explosive eruption is 14 .
14.
Use the descriptions and the photographs at the bottom of page 225 to mark each of the following statements True
or False.
15. Aa lava would be pleasant to walk across barefoot.
16. Pahoehoe lava flows in a smooth sheet.
17. Blocky lava moves quickly and spreads out evenly.
18. Pillow lava’s round shape is caused by contact with
19. When is pyroclastic material produced? (More than one answer possible)
a. as magma blasts from a volcano and solidifies in the air
b. as lava flows solidify
c. as existing rock is shattered by powerful explosions
d. as eruptions cause earthquakes
Using the descriptions on page 226, match each type of pyroclastic material in Column B with the correct
description in Column A, and write the corresponding letter in the appropriate space.
COLUMN A
COLUMN B
20. large blobs of magma that harden in the air.
a. volcanic blocks
21. solid rock that is blasted out of a volcano
b. volcanic bombs
22. glasslike slivers from the walls of exploding gas bubbles
c. lapilli
23. pebble-like bits of magma that cool in the air
d. volcanic ash
24. A theory that helps to explain the causes of both earthquakes and volcanoes is the
theory of
. [continental drift or plate tectonics]
25. Volcanic activity is common along the Mid-Atlantic Ridge. This activity occurs
at a
. [convergent boundary, subducted plate, or divergent boundary]
26. An explosive volcanic eruption can give flight to solid rock fragments called
[lava flows or pyroclastic material]
.
27. Silica-rich magma tends to harden in a volcano’s vent, often causing
.
a. nonexplosive eruptions
b. explosive eruptions
c. lava flows
d. earthquakes
28. Magma rises toward the surface of the Earth because it is
.
a. denser than the surrounding rock
b. full of air bubbles
c. less dense than the surrounding rock
d. the same density as the surrounding rock
29. Which lava erupts underwater, forming rounded lumps? [pahoehoe lava, aa lava,
or pillow lava]
30. Describe the type of magma that will produce a violent volcanic eruption such as Mount St. Helen's in 1980.
Diagram: Use the terms in the box to label the parts of the volcano.
TERM LIST
•magma
•lava
•vent
•crater
•volcanic cone
•dust, ash, and rock