Deck 5: Volcanoes and Volcanism

Question 1

What is vog, and who named it? What are its risks?

Answer 1

Vog is volcanic smog. The name was coined by residents of Hawaii who have been witnessing it since Kilauea began erupting in 1983. Volcanoes release carbon dioxide and sulfur dioxide, the latter of which produces a haze and unpleasant sulfurous odor. Vog may also result long-term health risks.

Question 2

How is volcanism destructive?

Answer 2

Some volcanic eruptions are explosive, and they eject a lot of material outward. Entire mountains may mostly disappear in a large eruption, and natural landscapes, human infrastructures destroyed, and lives can be claimed in an eruption.

Question 3

Describe the volcanoes that form the Hawaiian Islands, especially on the island of Hawaii.

Answer 3

The Hawaiian Islands are all shield volcanoes, which get older with distance from the Hawaiian hot spot, which lies beneath Kilauea. The island of Hawaii has five shield volcanoes, including Kilauea and another active volcano, Mauna Loa, which is nearly 100 km across and stands more than 9.5 km above the seafloor with a volume of 50,000 km³, making it the world's largest volcano.

Question 4

Look at the map of volcanoes of the world, and describe where most of the world's volcanoes are found.

Question 5

What is the volcanic explosivity index (VEI), and how is it determined?

Question 6

How is the behavior of gases different in a quiet and an explosive eruption?

Question 7

How could you distinguish a volcanic crater from a caldera?

Question 8

Describe composite volcanoes. How do they differ from shield volcanoes and cinder cones?

Question 9

What are the reasons that volcanism is primarily a constructive process?

Question 10

Mauna Loa volcano in Hawaii is huge and has gentle slopes; Mount Rainier in Washington is tall, with much steeper slopes; and Paricutín in Mexico is smaller and has very steep slopes composed of loose pyroclastic material. What type of volcano does each one represent, and what kind of volcanic activity was responsible for it?

Question 11

How do columnar joints form?

Question 12

Describe shield volcanoes. What are they composed of? Where are they found?

Question 13

How could carbon dioxide gas cause so many deaths in Cameroon?

Question 14

Briefly explain how magma can originate at spreading zones if temperatures at such shallow depths cannot produce melting.

Question 15

What is volcanism, and types of rocks formed as a result?

Question 16

Describe igneous activity at convergent plate boundaries.

Question 17

How are cinder cones different from the other two major types of volcanoes?

Question 18

Provide evidence as to why warning signals are not always indicative of impending volcanic eruptions?

Question 19

Why are the volcanoes of Hawaii shield volcanoes the same as spreading ridges?

Question 20

Discuss what volcanologists look for in trying to determine if a volcano is about to erupt.

Question 21

How do pillow lavas form?

Question 22

Would you rather be chased by a pahoehoe flow or an aa flow? Explain.

Question 23

Which magma type usually erupts from fissures?

Question 24

What are some of the techniques used to monitor volcanoes?

Question 25

How did recent eruptions of Mount Pinatubo in the Philippines and Kilauea in Hawaii differ?

Question 26

What produces columnar jointing in lava flows?

Question 27

According to plate tectonic theory, why are there volcanoes in Hawaii?

Question 28

Short Answer
What is the difference between an active volcano and a dormant volcano?

Question 29

Which type of volcano is Mount St. Helens?

Question 30

What does harmonic tremor indicate is happening beneath the surface of a volcano?

Question 31

Why are there volcanoes on the west coast of North America but not on the east coast?

Question 32

Distinguish aa from pahoehoe flows.

Question 33

Besides monitoring, what other piece of knowledge helps geologists in determining what to expect in eruptions from a given volcano?

Question 34

What is a lahar?

Question 35

Why are some places (e.g., northern California) more likely to experience volcanic eruptions than others (e.g., New York)?

Question 36

Why is Crater Lake in Oregon considered to be misnamed?

Question 37

Why does most volcanism at spreading ridges go undetected?

Question 38

What type of eruption is mainly responsible for producing plateau basalts?

Question 39

Give an example of a caldera.

Question 40

What other celestial bodies in the solar system are thought to have active volcanoes?

Question 41

Pyroclastic material that is less than 2 mm in diameter is called ____________________. Particles ranging from 2 to 64 mm in diameter are known as ____________________, while ____________________ and ____________________ are pieces larger than 64 mm in diameter.

Question 42

At Laki fissure in Iceland, due the eruption of the gas ____________________ crops failed and caused about 75% of the nation's livestock and 25% of the population to perish.

Question 43

Composite volcanoes are also known as ____________________ and are composed of both ____________________ flows and ____________________ material.

Question 44

Columnar joints caused by the contraction of lava as it cools form typically in a(n) ____________________ shape.

Question 45

The two most active volcanic zones are the ____________________ belt and the ____________________ belt.

Question 46

One indicator of an impending volcanic eruption that precedes all Hawaiian volcanic eruptions is a continuous ground motion called ____________________.

Question 47

Sometimes, the pyroclastic material that flows from a volcano is so hot that it fuses together to form a deposit known as ____________________.

Question 48

Lavas of ____________________ composition are more likely to produce lava domes.

Question 49

Composite volcanoes are composed of the igneous rock type known as ____________________, which forms from lava of ____________________ composition and viscosity.

Question 50

Pahoehoe is lava erupted by Hawaiian volcanoes that has a(n) ____________________ viscosity and a(n) ____________________ appearance.

Question 51

The most volcanically active region of the contiguous United States is the ____________________.

Question 52

One common but dangerous gas emitted from volcanoes, which was responsible for many deaths in Cameroon, is ____________________.

Question 53

Shield volcanoes are composed largely of lavas of ____________________ composition, they commonly have slopes that are ____________________, and their eruptions tend to be ____________________ in explosivity.

Question 54

The type of volcano that is the most common in the two major volcanic belts on Earth is ____________________.

Question 55

The one place on Earth where mid-oceanic ridge volcanism occurs above sea level is ____________________.

Question 56

Volcanic activity that takes place away from plate boundaries is the result of volcanism at a(n) ____________________. In the U.S., an example of this type of volcanism in the ocean is ____________________; an example on land is ____________________.

Question 57

Volcanism occurs along the following two types of plate boundaries: ____________________ and ____________________.

Question 58

The dominant gas emitted from volcanoes is ____________________.

Question 59

Completion
When basalt lava is chilled rapidly in the water in an ocean or lake, it forms bulbous structures called ____________________.

Question 60

Cinder cones rarely reach heights greater than ____________________; they are composed of ____________________ material of ____________________ composition.

Question 61

Nuée ardentes erupt from:

A) supervolcanoes.
B) shield volcanoes.
C) fissures.
D) lava domes.
E) cinder cones.

Question 62

Which is the correct ranking (in descending order) of regions with the most active volcanoes and volcanic activity?      1. Circum-Pacific belt
     2. Mid-oceanic ridges
     3. Mediterranean belt
     4. Isolated sites like the Hawaiian Islands

A) 2, 1, 3, 4
B) 1, 3, 2, 4
C) 2, 3, 4, 1
D) 1, 2, 3, 4
E) 3, 2, 1, 4

Question 63

True/False
A volcano is considered extinct if it has not erupted for more than 1,000 years.

Question 64

A lava tube is a hollow space left when the lava within a flowing tube drains away, leaving only the outside as hardened rock.

Question 65

An example of a caldera is:

A) Mount St. Helens, Washington.
B) Paricutín, Mexico.
C) El Chichon, Mexico.
D) Krakatau, Java.
E) Crater Lake, Oregon.

Question 66

Intermediate and felsic magmas usually arise where:

A) mafic magma mixes with felsic material.
B) volcanoes lie on continental margins inland of subduction zones.
C) plates diverge as spreading ridges form.
D) volcanoes lie above transform faults.
E) mafic magma mixes with felsic material AND volcanoes lie on continental margins inland of subduction zones.

Question 67

An example of a shield volcano is:

A) Kilauea.
B) Mount St. Helens.
C) Mount Shasta.
D) Mount Mazama.
E) Fujiyama.

Question 68

Basalt plateaus erupt from:

A) supervolcanoes.
B) shield volcanoes.
C) fissures.
D) lava domes.
E) cinder cones.

Question 69

Multiple Choice An extinct volcano is one that:

A) existed during a past geological period or epoch.
B) has not erupted during recorded history.
C) has shown no evidence of activity over recorded history.
D) has not erupted during recorded history and has shown no evidence of activity over recorded history.
E) all of these

Question 70

An example of a cinder cone volcano is:

A) Mount St. Helens, Washington.
B) Mayon, Philippines.
C) Paricutín, Mexico.
D) Vesuvius, Italy.
E) Mazama, Oregon.

Question 71

Earth is the most volcanically active body in our solar system.

Question 72

Pyroclastic materials include:

A) volcanic bombs, pillow lavas, and volcanic ash.
B) volcanic bombs, lapilli, and volcanic ash.
C) pillow lavas and nuée ardentes.
D) nuée ardentes and lahars.
E) none of these

Question 73

Lava domes form from:

A) mafic magma.
B) intermediate magma.
C) viscous magma.
D) pyroclastic materials.
E) basalt.

Question 74

The three main types of volcanoes are:

A) cinder cones, clastic cones, and stratocones.
B) cinder cones, composite volcanoes, and shield volcanoes.
C) shield volcanoes, composite volcanoes, and Hawaiian-style volcanoes.
D) clastic cones, stratocones, and Hawaiian-style volcanoes.
E) none of the above

Question 75

An example of a composite volcano is:

A) Fujiyama, Japan.
B) Nevado del Ruiz, Columbia.
C) Mount Vesuvius, Italy.
D) Mount St. Helens, Washington.
E) all of the above

Question 76

The chemical composition of all lavas is the same.

Question 77

The volcanic explosivity index (VEI) is intended to:

A) describe the frequency of volcanoes.
B) be used to forecast eruptions.
C) prevent fatalities and property damage.
D) document the size of eruptions.
E) encourage people not to live near active volcanoes.

Question 78

Most of the approximately 3,300 historic eruptions lasted:

A) less than one month.
B) one to six months.
C) one to two years.
D) more than two years.
E) none of these

Question 79

Volcanism profoundly affects the atmosphere, hydrosphere, and biosphere.

Question 80

Most volcanoes are located in:

A) the Mediterranean belt.
B) the mid-oceanic ridges.
C) the circum-Pacific belt.
D) the East African Rift Zone.
E) Indonesia.