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Lesson
Name _______________________________________________ Date ________________ Class______________
DATASH EET
17
STUDENT WORKSHEET
Some Go “Pop,” Some Do Not
Volcanic eruptions range from mild to violent. When volcanoes erupt, the materials
left behind provide information to scientists studying the Earth’s crust. Mild, or nonexplosive, eruptions produce thin, runny lava that is low in silica. During nonexplosive eruptions, lava simply flows down the side of the volcano. Explosive eruptions,
on the other hand, do not produce much lava. Instead, the explosions hurl ash and
debris into the air. The materials left behind are light in color and high in silica.
These materials help geologists determine the composition of the crust underneath
the volcanoes.
MATERIALS
• graph paper
• metric ruler
• red, yellow, and
orange colored
pencils or markers
Procedure
1. Look at the map below.
60°N
30°N
0°
30°S
60°S
0°
30°E
60°E
90°E
120°E
150°E
180°
150°W
120°W
90°W
60°W
30°W
2. Locate each volcano from the Volcanic Activity Chart by
drawing a circle with a diameter of about 1 cm in the proper
location on the map. Use the latitude and longitude grids to
help you.
3. Review all the eruptions for each volcano. For each explosive eruption, color the circle red. For each quiet volcano,
color the circle yellow. For volcanoes that have erupted in
both ways, color the circle orange.
54
HOLT SCIENCE AND TECHNOLOGY
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name _______________________________________________ Date ________________ Class______________
Some Go “Pop,” Some Do Not, continued
Volcano name
Location
Description
Mount St. Helens
46°N 122°W
An explosive eruption blew the top off the mountain.
Light-colored ash covered thousands of square kilometers. Another eruption sent a lava flow down the
southeast side of the mountain.
Kilauea
19°N 155°W
One small eruption sent a lava flow along 12 km of
highway.
Rabaul caldera
4°S 152°E
Explosive eruptions have caused tsunamis and have
left 1–2 m of ash on nearby buildings.
Popocatépetl
19°N 98°W
During one explosion, Mexico City closed the airport
for 14 hours because huge columns of ash made it too
difficult for pilots to see. Eruptions from this volcano
have also caused damaging avalanches.
Soufriere Hills
16°N 62°W
Small eruptions have sent lava flows down the hills.
Other explosive eruptions have sent large columns of
ash into the air.
Long Valley caldera
37°N 119°W
Explosive eruptions have sent ash into the air.
Okmok
53°N 168°W
Recently, there have been slow lava flows from this
volcano. Twenty-five hundred years ago, ash and debris
exploded from the top of this volcano.
Pavlof
55°N 161°W
Eruption clouds have been sent 200 m above the
summit. Eruptions have sent ash columns 10 km into
the air. Occasionally, small eruptions have caused lava
flows.
Fernandina
42°N 12°E
Eruptions have ejected large blocks of rock from this
volcano.
Mount Pinatubo
15°N 120°E
Ash and debris from an explosive eruption destroyed
homes, crops, and roads within 52,000 km2 around
the volcano.
Analyze the Results
4. According to your map, where are volcanoes that always
have nonexplosive eruptions located?
DATASHEETS FOR LABBOOK
55
CHAPTER 9
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Volcanic Activity Chart
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Name _______________________________________________ Date ________________ Class______________
Some Go “Pop,” Some Do Not, continued
5. Where are volcanoes that always erupt explosively located?
6. Where are volcanoes that erupt in both ways located?
7. If volcanoes get their magma from the crust below them,
what can you say about the silica content of Earth’s crust
under the oceans?
8. What is the composition of the crust under the continents?
How do we know?
9. What is the source of materials for volcanoes that erupt in
both ways? How do you know?
56
HOLT SCIENCE AND TECHNOLOGY
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name _______________________________________________ Date ________________ Class______________
Some Go “Pop,” Some Do Not, continued
10. Do the locations of volcanoes that erupt in both ways
make sense based on your answers to questions 7 and 8?
Explain.
Volcanoes are present on other planets. If a planet had only
nonexplosive volcanoes on its surface, what would we be able
to infer about the planet? If a planet had volcanoes that ranged
from nonexplosive to explosive, what might that tell us about
the planet?
CHAPTER 9
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Going Further
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DATASHEETS FOR LABBOOK
57
Print
Lesson
Name _______________________________________________ Date ________________ Class______________
DATASH EET
17
STUDENT WORKSHEET
Some Go “Pop,” Some Do Not
Volcanic eruptions range from mild to violent. When volcanoes erupt, the materials
left behind provide information to scientists studying the Earth’s crust. Mild, or nonexplosive, eruptions produce thin, runny lava that is low in silica. During nonexplosive eruptions, lava simply flows down the side of the volcano. Explosive eruptions,
on the other hand, do not produce much lava. Instead, the explosions hurl ash and
debris into the air. The materials left behind are light in color and high in silica.
These materials help geologists determine the composition of the crust underneath
the volcanoes.
MATERIALS
• graph paper
• metric ruler
• red, yellow, and
orange colored
pencils or markers
Procedure
1. Look at the map below.
60°N
30°N
0°
30°S
60°S
0°
30°E
60°E
90°E
120°E
150°E
180°
150°W
120°W
90°W
60°W
30°W
2. Locate each volcano from the Volcanic Activity Chart by
drawing a circle with a diameter of about 1 cm in the proper
location on the map. Use the latitude and longitude grids to
help you.
3. Review all the eruptions for each volcano. For each explosive eruption, color the circle red. For each quiet volcano,
color the circle yellow. For volcanoes that have erupted in
both ways, color the circle orange.
54
HOLT SCIENCE AND TECHNOLOGY
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Menu
Print
Lesson
Name _______________________________________________ Date ________________ Class______________
Some Go “Pop,” Some Do Not, continued
Volcano name
Location
Description
Mount St. Helens
46°N 122°W
An explosive eruption blew the top off the mountain.
Light-colored ash covered thousands of square kilometers. Another eruption sent a lava flow down the
southeast side of the mountain.
Kilauea
19°N 155°W
One small eruption sent a lava flow along 12 km of
highway.
Rabaul caldera
4°S 152°E
Explosive eruptions have caused tsunamis and have
left 1–2 m of ash on nearby buildings.
Popocatépetl
19°N 98°W
During one explosion, Mexico City closed the airport
for 14 hours because huge columns of ash made it too
difficult for pilots to see. Eruptions from this volcano
have also caused damaging avalanches.
Soufriere Hills
16°N 62°W
Small eruptions have sent lava flows down the hills.
Other explosive eruptions have sent large columns of
ash into the air.
Long Valley caldera
37°N 119°W
Explosive eruptions have sent ash into the air.
Okmok
53°N 168°W
Recently, there have been slow lava flows from this
volcano. Twenty-five hundred years ago, ash and debris
exploded from the top of this volcano.
Pavlof
55°N 161°W
Eruption clouds have been sent 200 m above the
summit. Eruptions have sent ash columns 10 km into
the air. Occasionally, small eruptions have caused lava
flows.
Fernandina
42°N 12°E
Eruptions have ejected large blocks of rock from this
volcano.
Mount Pinatubo
15°N 120°E
Ash and debris from an explosive eruption destroyed
homes, crops, and roads within 52,000 km2 around
the volcano.
Analyze the Results
4. According to your map, where are volcanoes that always
have nonexplosive eruptions located?
Nonexplosive volcanoes are usually located on oceanic crust.
DATASHEETS FOR LABBOOK
55
CHAPTER 9
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Volcanic Activity Chart
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Lesson
Name _______________________________________________ Date ________________ Class______________
Some Go “Pop,” Some Do Not, continued
5. Where are volcanoes that always erupt explosively located?
Explosive volcanoes are usually located on continental crust.
6. Where are volcanoes that erupt in both ways located?
Volcanoes that erupt in both ways are usually located near boundaries
between oceanic and continental crust.
7. If volcanoes get their magma from the crust below them,
what can you say about the silica content of Earth’s crust
under the oceans?
The crust under the oceans must be low in silica. Students may also
know that the crust is likely to be made of basalt.
8. What is the composition of the crust under the continents?
How do we know?
Continental crust is generally high in silica. Students may also know
that the crust is likely to be made of granite.
9. What is the source of materials for volcanoes that erupt in
both ways? How do you know?
The volcanoes that erupt in both ways must be near the boundary
between the oceanic crusts and the continental crusts. The crust must
have both basalt and granite.
56
HOLT SCIENCE AND TECHNOLOGY
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Lesson
Name _______________________________________________ Date ________________ Class______________
Some Go “Pop,” Some Do Not, continued
10. Do the locations of volcanoes that erupt in both ways
make sense based on your answers to questions 7 and 8?
Explain.
The volcanoes that erupt in both ways are located near continents
and oceans. Students should be able to understand that two different
crusts must meet in these areas and that both granitic (felsic) and
basaltic (mafic) magma is generated.
Volcanoes are present on other planets. If a planet had only
nonexplosive volcanoes on its surface, what would we be able
to infer about the planet? If a planet had volcanoes that ranged
from nonexplosive to explosive, what might that tell us about
the planet?
Answers should reflect the idea that the crust on planets with nonexplosive
volcanoes must be low in silica compared to Earth. Students may also
realize that planets that have only nonexplosive volcanoes must have
basaltic crust. If a planet has all three types of volcanoes, it must have
both basaltic and granitic crust.
CHAPTER 9
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Going Further
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DATASHEETS FOR LABBOOK
57