Question 1

How might you escape from a lahar?

Accepted Answer

A)   Swim to safety in the flow
B)   Outrun the lahar because it is slow
C)   Float in a boat in the lahar
D)   Run up an embankment away from the flow
E)   Walk on top of the flow because it is so thickF) B) and C)
G) B) and D)

Question 2

Explain what viscosity is and how it affects the shape of a volcano. Give one example to illustrate your point.

Accepted Answer

Viscosity is the resistance to flow. Hig...

Question 3

The history of an area's rocks can give a timeline of past volcanic eruptions.

Accepted Answer

A) True 
 B)False

Question 4

Composite volcanoes can have a long dormant period in which people can forget that they were ever once active volcanoes.

Accepted Answer

A) True 
 B)False

Question 5

What is the difference between magma and lava?

Accepted Answer

A)   Magma is molten rock, lava is hot solid rock and water.
B)   Magma is black, lava is red.
C)   Magma is found below the Earth's surface, lava is found on the Earth's surface.
D)   Magma is found on the ocean floor, lava is found on land surfaces.
E)   There is no difference between lava and magma.F) A) and B)
G) B) and C)

Question 6

Describe the hazards associated with an ash fall.

Accepted Answer

Hazards of ashfalls include de...

Question 7

Which volcano type involves layers of pyroclastic debris and lava flows?

Accepted Answer

A)   Shield volcano
B)   Stratovolcano
C)   Lava dome
D)   Cinder coneE) A) and B)
F) B) and D)

Question 8

Unfortunately, volcanoes do not give any signs or indications of when they might erupt.

Accepted Answer

A) True 
 B)False

Question 9

The area around Mt. St. Helens is now safe because the volcano is finished erupting and will stay dormant for the next 200 years.

Accepted Answer

A) True 
 B)False

Question 10

People have successfully diverted lava flows from populated areas.

Accepted Answer

A) True 
 B)False

Question 11

Why do scientists study earthquakes to predict a volcanic eruption?

Accepted Answer

A)   When magma moves, it causes earthquakes.
B)   Earthquakes break the earth apart and cause magma to appear at the surface.
C)   All big earthquakes are caused by magma erupting.
D)   Groundwater moves before an eruption, causing earthquakes.E) All of the above
F) C) and D)

Question 12

Volcanoes associated with high viscosity magma are usually less dangerous than those with more freely flowing magma.

Accepted Answer

A) True 
 B)False

Question 13

Why are so many volcanoes found on the Ring of Fire around the margin of the Pacific Ocean?

Accepted Answer

A)   Many hotspots occur there.
B)   Many subduction zones occur there.
C)   The Pacific Ocean is very hot, causing rock to melt.
D)   The climate is hot there, favoring volcano formation.
E)   The seafloor is spreading extremely fast there.F) A) and B)
G) A) and E)

Question 14

Most volcanoes are around the Pacific Ocean's "Ring of Fire." Explain why they are there and what kind of volcanoes form there.

Accepted Answer

Most of the world's volcanoes are around...

Question 15

There has never been a globally catastrophic volcanic eruption from Iceland's volcanoes because they only involve gentle lava flows.

Accepted Answer

A) True 
 B)False

Question 16

In which two environments are shield volcanoes found?

Accepted Answer

A)   Hotspots in the ocean and subduction zones
B)   Hotspots on land and divergent plate boundaries
C)   Divergent plate boundaries and subduction zones
D)   Hotspots on land and subduction zones
E)   Hotspots in the ocean and divergent plate boundariesF) B) and C)
G) B) and E)

Question 17

Explain the difference between magma formed at subduction zones and divergent plate boundaries.

Accepted Answer

Magma formed at subduction zon...

Question 18

Where does tephra come from?

Accepted Answer

A)   It is the volcanic rock and lava blasted into the air or carried by gases.
B)   It is from the inner part of a gently erupted lava flow.
C)   It represents broken pieces of the volcano and is produced by weathering and erosion.
D)   It is mud associated with a mudflow that was triggered by a volcanic eruption.E) All of the above
F) B) and D)

Question 19

Caldera eruptions can involve the largest volcanic eruptions on earth and they are the rarest.

Accepted Answer

A) True 
 B)False

Question 20

Magma with a higher silica content will also have a higher viscosity.

Accepted Answer

A) True 
 B)False

Exam 5: Volcanoes

Magma with a higher silica content will also have a higher viscosity.

Correct AnswerverifiedShow Answer

The area around Mt. St. Helens is now safe because the volcano is finished erupting and will stay dormant for the next 200 years.

Correct AnswerverifiedShow Answer

Which volcano type involves layers of pyroclastic debris and lava flows?

Correct AnswerverifiedShow Answer

Explain the difference between magma formed at subduction zones and divergent plate boundaries.

Correct AnswerverifiedMagma formed at subduction zon...View AnswerShow Answer

Unfortunately, volcanoes do not give any signs or indications of when they might erupt.

Correct AnswerverifiedShow Answer

Volcanoes associated with high viscosity magma are usually less dangerous than those with more freely flowing magma.

Correct AnswerverifiedShow Answer

What is the difference between magma and lava?

Correct AnswerverifiedShow Answer

In which two environments are shield volcanoes found?

Correct AnswerverifiedShow Answer

The history of an area's rocks can give a timeline of past volcanic eruptions.

Correct AnswerverifiedShow Answer

People have successfully diverted lava flows from populated areas.

Correct AnswerverifiedShow Answer

There has never been a globally catastrophic volcanic eruption from Iceland's volcanoes because they only involve gentle lava flows.

Correct AnswerverifiedShow Answer

Caldera eruptions can involve the largest volcanic eruptions on earth and they are the rarest.

Correct AnswerverifiedShow Answer

Where does tephra come from?

Correct AnswerverifiedShow Answer

Why are so many volcanoes found on the Ring of Fire around the margin of the Pacific Ocean?

Correct AnswerverifiedShow Answer

Most volcanoes are around the Pacific Ocean's "Ring of Fire." Explain why they are there and what kind of volcanoes form there.

Correct AnswerverifiedMost of the world's volcanoes are around...View AnswerShow Answer

Explain what viscosity is and how it affects the shape of a volcano. Give one example to illustrate your point.

Correct AnswerverifiedViscosity is the resistance to flow. Hig...View AnswerShow Answer

Describe the hazards associated with an ash fall.

Correct AnswerverifiedHazards of ashfalls include de...View AnswerShow Answer

Why do scientists study earthquakes to predict a volcanic eruption?

Correct AnswerverifiedShow Answer

Composite volcanoes can have a long dormant period in which people can forget that they were ever once active volcanoes.

Correct AnswerverifiedShow Answer

How might you escape from a lahar?

Correct AnswerverifiedShow Answer

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Magma formed at subduction zon...
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Most of the world's volcanoes are around...
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Viscosity is the resistance to flow. Hig...
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Correct Answer
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Hazards of ashfalls include de...
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Correct Answer
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