Deck 5: Volcanoes and Volcanism

Question 1

The volcano that buried Vesuvius and Herculaneum is no longer a threat to people living nearby.

Answer 1

False

Question 2

Volcanism is primarily a destructive process.

Answer 2

False

Question 3

The chemical composition of lava is the same for all volcanoes.

Answer 3

False

Question 4

Lava tubes form when the lava enters and flows through caves in the rock flanking the volcano.

Question 5

Pyroclastic materials can consist of both solid and partially molten material.

Question 6

A nuée ardente may travel at speeds as high as 100 kilometers per hour.

Question 7

Columnar jointing is the result of cooling and contraction of magma and lava.

Question 8

The difference between calderas and craters is that craters are constructed around central vents and calderas result from the collapse of lava flows.

Question 9

Shield volcanoes are most common in ocean basins because lava composition is basaltic and non-explosive.

Question 10

Composite volcanoes are typically formed from intermediate magmas which are more viscous and explosive.

Question 11

Yellowstone National Park was formed as a result of the eruption of a series of supervolcanoes.

Question 12

Mount Lassen was the last of the Cascade volcanoes to be active.

Question 13

The Columbia River basalts and the plateau they form are sourced in the adjacent Cascade Range volcanoes.

Question 14

Harmonic tremors are indicative of magma moving beneath the surface and may be significant for forecasts of volcanic activity.

Question 15

Pyroclastic sheet flows are the result of volcanic eruptions from central vents during periods of especially strong winds.

Question 16

The circum-Pacific belt of volcanoes is related to subduction of tectonic plates.

Question 17

The distribution of active volcanoes is random.

Question 18

The volcanic explosivity index quantifies the energy of a volcanic eruption.

Question 19

Which of the following statements most accurately describes Mount Vesuvius?

A) Since the eruptions that buried Pompeii and Herculaneum, it has not been active.
B) It has been active but no longer threatens human life.
C) It has erupted often and killed many since the eruptions that buried Pompeii and Herculaneum.

Question 20

An extinct volcano is one which

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) B and C, only
E) all of the above

Question 21

Aa lava is different from pahoehoe lava because

A) it is more viscous
B) it has a more felsic or silicic composition
C) it is cooler
D) A and B
E) all of the above.

Question 22

The type of volcano that forms over time is not dependent on which of the following characteristics:

A) type of tectonic plate boundary
B) composition of the magma
C) temperature of the magma
D) previous volcanic activity

Question 23

Composite volcanoes form from

A) intermediate or andesitic magmas
B) lava flows
C) pyroclastic flows
D) lahars
E) B, C, and D
F) all of the above

Question 24

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) A and B

Question 25

Volcanism occurs along which of the following? The majority of volcanoes occur along

A) divergent plate margins below sea level
B) divergent plate margins above sea level
C) oceanic-oceanic convergent plate margins
D) oceanic-continental convergent plate margins
E) A and C
F) A, C, and D
G) all of the above

Question 26

Magmas with mafic compositions would most likely form volcanoes

A) along convergent margins involving oceanic and continental crust
B) along divergent mid-oceanic ridges
C) over continental hotspots
D) between plates along a transform boundary

Question 27

One common and dangerous gas emitted from volcanoes and responsible for many deaths in Iceland and Camaroon in the past is___________ .

Question 28

Basalt lava when chilled rapidly beneath water forms bulbous structures called___________.

Question 29

Pahoehoe is a lava ejected by Hawaiian volcanoes that has a (high/intermediate/low)___________viscosity and a ___________ appearance.

Question 30

An eruption of hundreds of cubic kilometers of pyroclastic material that results in the formation of a caldera is termed a ___________.

Question 31

Shield volcanoes are composed largely of (basalt/andesite/rhyolite)___________ flows, commonly have (steep/intermediate/gentle)___________ slopes, and their eruptions tend to be (explosive/quiet/very explosive) ___________.

Question 32

Prior to the 1980 eruption of Mt. St. Helens, the last eruption of a Cascade Range volcano was that of___________in the years ___________ .

Question 33

Although rocks at depth are hot, they remain solid because their melting point (increases/decreases)___________as the pressure (increases/decreases) ___________ .

Question 34

Composite volcanoes are typical along___________ plate boundaries.

Question 35

___________magma produces shield volcanoes along___________ plate boundaries.

Question 36

Are felsic or mafic volcanoes more likely to produce lava domes? Explain.

Question 37

Distinguish and explain the difference between aa and pahoehoe lava.

Question 38

Mauna Loa volcano in Hawaii has relatively gentle slopes; Mt. Rainier in Washington is tall, with steeper slopes; Parícutin in Mexico is much smaller, with very steep slopes composed of loose pyroclastic material. Each of these is an example of a different kind of volcano. What kind does each represent? What kind of volcanic activity produced each of these? Why are there different types of volcanos? Explain.

Question 39

Describe a type of measurement which has been used to forecast volcanic eruptions. What is the physical basis for the volcanic phenomena that they represent?

Question 40

Are volcanoes generally active over short periods of time or long or geologic periods of time?

Question 41

Why are fissure eruptions associated with basalt plateaus?

Question 42

Why are basalt plateau's elevated?

Question 43

What was the date of the eruptions that destroyed the Roman cities of Pompeii and Herculaneum?

Question 44

What volcano was responsible for the destruction of Pompeii and Herculaneum?

Question 45

Give one reason why volcanism is considered to be a constructive process.

Question 46

What do pillow lavas indicate about a lava flow?

Question 47

Fissure eruptions are usually associated with which magma type?

Question 48

How does a volcanic crater differ from a volcanic caldera?

Question 49

Approximately how many people live near volcanoes on the margins of Earth's tectonic plates?

Question 50

What type of volcanos are most common in the two most active volcanic belts on Earth?

Question 51

Although most of the volcanism along the Mid-Atlantic Ridge is submarine, where is one place where it occurs above sea level?

Question 52

Volcanism occurs along which plate boundary type(s)?

Question 53

Besides monitoring, what else is necessary to forecast eruptions for a given volcano?

Question 54

How can we explain volcanic activity within the interior of a plate (i.e., not at a plate boundary)?

Question 55

Explain why most of the world's volcanoes are within the circum-Pacific belt.

Question 56

Give an example of a place with hot spot volcanic activity.