Deck 6: Volcanoes and Volcanic Hazards

Question 1

This volcano is broad and low, and is composed of basaltic lava flows. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) volcanic dome
E) caldera

Answer 1

B

Question 2

What type of volcanic eruption is shown in this photograph?

A) a lava fountain
B) collapse of a volcanic dome
C) a fissure eruption
D) a pyroclastic column
E) a volcanic mudflow

Answer 2

D

Question 3

Which of the following is least likely to be a volcano?

A) a vent where magma and other volcanic material is erupted
B) a hill with a crater formed at the site of an eruption
C) a hill capped by volcanic rocks
D) a fissure that erupts hot, molten lava
E) a mountain that erupts only volcanic ash

Answer 3

C

Question 4

This relatively small volcanic feature consists of solidified lava and some volcanic ash. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) caldera
E) none of these

Question 5

This relatively large, symmetrical volcano contains interlayered lava flow, pyroclastic deposits, and volcanic mudflows. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) volcanic dome
E) caldera

Question 6

What event triggered the main eruption of May 1980?

A) Melting snow caused a huge steam eruption.
B) Magma encountered groundwater and exploded.
C) A landslide removed rocks and released pressure on the magma.
D) All of these.

Question 7

This volcano is broad and low, and is composed of basaltic lava flows. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) volcanic dome
E) caldera

Question 8

This relatively large, symmetrical volcano contains interlayered lava flow, pyroclastic deposits, and volcanic mudflows. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) volcanic dome
E) fissure

Question 9

Which of the following types of volcanic eruption have occurred on Mount St. Helens since it began erupting in 1980?

A) eruption column
B) pyroclastic flow
C) volcanic dome
D) all of these

Question 10

Which of the following best describes the temperature of materials typically erupted from volcanoes?

A) Extremely hot
B) Warm to slighty hot
C) Cool to cold

Question 11

Huge circular depressions from which volcanoes erupt are called:

A) calderas
B) fissures
C) cones

Question 12

Which of the following are characteristics of actively erupting volcanoes?

A) Glowing orange lava flowing downhill
B) Fragments of molten rock blasting into the air
C) Billowing clouds of ash rising into the air
D) All of these

Question 13

Which of the following is NOT a typical characteristic of a volcano?

A) Conical-shaped hill
B) Crater at or near the top of a hill
C) Fresh ash layers or lava flows covering part of a conical hill
D) Flat-topped mesa with eroded volcanic rock cliffs at that top

Question 14

Which of the following is typically erupted from a volcano?

A) Scalding hot ash, lava, and gases
B) Ice and snow, combined with steam
C) Large quantities of liquid water

Question 15

Which of the following volcanoes is generally the largest?

A) scoria cone
B) dome
C) composite volcano
D) shield volcano

Question 16

The typical shape of most volcanoes, including the one shown here, is:

A) conical
B) cylindrical
C) domical

Question 17

This relatively small volcanic feature consists of solidified lava and some volcanic ash. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) volcanic dome
E) caldera

Question 18

This volcano is relatively small and composed of volcanic cinders. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) volcanic dome
E) caldera

Question 19

Which of the following is NOT a characteristic of an actively erupting volcano?

A) Totally covered in a fresh blanket of clean, white snow
B) Billowing ash column rising into the sky
C) Glowing lava flows moving down mountain slopes
D) Rapidly melting glaciers/snowpack producing massive mudflows

Question 20

This volcano is relatively small and composed of volcanic cinders. What kind of volcano is it?

A) scoria cone
B) shield volcano
C) composite volcano
D) volcanic dome
E) caldera

Question 21

At what depth do gas bubbles have the most effect on magma?

A) when the magma first forms, before the bubbles can dissolve into the magma
B) at moderate depths, when the magma is moving rapidly through the conduit
C) at very shallow levels, such as within the volcano
D) none of these

Question 22

Comparing these two photographs, which eruption has lower viscosity magma?

A) the fluid cascade of lava
B) the circular volcanic feature
C) they could have the same viscosity
D) there is no way to tell

Question 23

When fluid lava erupts onto the surface, it typically produces:

A) lava flows
B) lava domes
C) ash columns
D) pyroclastic flows

Question 24

What type of eruption is shown in this photograph?

A) lava flow
B) lava dome
C) lava fountain
D) pyroclastic column
E) pyroclastic flow

Question 25

Which of the following are differences between an eruption column and pyroclastic flow?

A) Tephra in an eruption column stays hotter until it reaches the ground.
B) A pyroclastic flow rises higher into the atmosphere than an eruption column.
C) Damage from an eruption column is more restricted than a pyroclastic flow.
D) A pyroclastic flow forms when the gas flux cannot support the column.

Question 26

If bubbles cannot escape easily from a magma, the resulting eruption is likely to:

A) be explosive
B) be nonexplosive
C) produce long, thin lava flows

Question 27

What type of eruption is shown in this photograph?

A) lava flow
B) lava dome
C) lava fountain
D) pyroclastic flow

Question 28

What type of eruption is shown in this photograph?

A) lava flow
B) lava dome
C) lava fountain
D) pyroclastic column
E) pyroclastic flow

Question 29

Which of the following materials is NOT produced by erupting volcanoes?

A) sandstone
B) basaltic lava
C) obsidian/glass
D) ash

Question 30

A single volcano may produce:

A) Only explosive eruptions
B) Only nonexplosive eruptions
C) Bothe explosive and nonexplosive eruptions
D) Either explosive or nonexplosive eruptions, but never both

Question 31

Which of the following are NOT differences between an eruption column and pyroclastic flow?

A) Tephra in an eruption column mostly cools before it reaches the ground.
B) A pyroclastic flow mostly flows downhill, whereas a column rises at first.
C) Damage from an eruption column can be more widespread.
D) Pyroclastic flows form from a higher gas flux.

Question 32

Which of the following is NOT evidence of recent activity at a volcano?

A) Thick, well-developed soil
B) Layer of ash blanketing hillslopes
C) Unweathered lava flows
D) Ash flows lacking a well-developed soil

Question 33

Which of the following are erupted by volcanoes?

A) lava
B) ash
C) pumice
D) all of these

Question 34

Which of the following is NOT a common type of volcano?

A) mesa
B) shield
C) dome
D) composite cone

Question 35

Which of the following would be evidence that a volcano has NOT been active for a long period of time?

A) A layer of ash blanketing hillslopes
B) Relatively unweathered lava flows
C) Well-developed soils on volcanic rocks

Question 36

Which of the following lists the four types of volcanoes shaped like hills and mountains?

A) Scoria cone, shield, composite, dome
B) Fissure, shield, scoria cone, dome
C) Crater, scoria cone, crater, dome

Question 37

Which of the following are ways that viscosity affects gases in magma?

A) Viscous magma prevents gas from escaping easily.
B) Abundant silica chains in viscous magma allow gas to pass quickly through the magma.
C) Less viscous magma allows gas to escape, which can lead to very explosive eruptions.
D) All of these.

Question 38

Which of the following is NOT a major controlling factor on volcanic eruption style?

A) Age of volcano
B) Chemistry of the magma
C) Magma volatile content

Question 39

What type of eruption is shown in this photograph?

A) lava flow
B) lava dome
C) lava fountain
D) pyroclastic column
E) pyroclastic flow

Question 40

Long, thin lava flows are typically produced by:

A) volatile-rich eruptions
B) high-viscosity lavas
C) low-viscosity lavas
D) collapsing eruption columns

Question 41

Which of the following occurs in a lava tube?

A) The surface of the lava flow solidifies to form a roof over the moving lava.
B) Lava tubes insulate a lava flow, allowing it to flow farther.
C) If a lava tube drains, it becomes a tube-shaped cave.
D) All of these.

Question 42

Eruptions of scoria cones are commonly associated with:

A) basaltic lava flows
B) lava fountains
C) pyroclastic flow
D) viscous lava flows
E) basaltic lava flows and lava fountains

Question 43

What type of eruption formed the small volcano in this photograph?

A) fluid lava flows
B) eruption of viscous lava
C) lava fountain
D) eruption column
E) pyroclastic flow

Question 44

Which of the following are true of felsic magmas?

A) They tend to have high viscosities.
B) They do not allow gas bubbles to escape easily
C) High gas pressures commonly lead to highly explosive eruptions.
D) All of these

Question 45

Which of the following is common in lava flows associated with scoria cones?

A) Some scoria cones are not accompanied by a lava flow and vice versa.
B) Some lava flows squeeze out near the base of the scoria cone.
C) The lava flow forms before the scoria cone when gas contents are highest.
D) The lava flows are mostly intermediate to felsic.
E) a and b only

Question 46

What types of rocks would be most common in the volcano shown in this photograph?

A) scoria
B) basalt mostly formed in lava flows
C) felsic and intermediate lava flows
D) tuff and tephra
E) none of these

Question 47

What is the main type of eruption that formed the volcano in this photograph?

A) fluid lava flows
B) eruption of viscous lava
C) lava fountain
D) eruption column
E) pyroclastic flow

Question 48

What type of basaltic feature is shown in this photograph?

A) vesicles
B) volcanic bomb
C) aa lava flow
D) pahoehoe lava flow
E) pyroclastic flow

Question 49

What types of rocks would be most common in the small volcano in this photograph?

A) scoria and other vesicular basalt
B) basalt mostly formed in lava flows
C) felsic and intermediate lava flows
D) welded tuff and tephra
E) none of these

Question 50

Which of the following is NOT true of basaltic lava flows?

A) They flow downhill from the vent area
B) They pile up in steep, cone-shaped hills
C) They form from nonexplosive eruptions
D) They can issue from the bases of scoria cones

Question 51

Shield volcanoes commonly have:

A) fissure eruptions
B) lava flows
C) fire fountains
D) dikes at depth
E) all of these

Question 52

What type of basaltic feature is shown in this photograph?

A) vesicles
B) volcanic bomb
C) aa lava flow
D) pahoehoe lava flow
E) pyroclastic flow

Question 53

Shield volcanoes commonly involve:

A) fluid lava flows
B) volcanic domes
C) viscous lava flows
D) pyroclastic flows
E) all of these

Question 54

Compared to a younger scoria cone, an older scoria cone would have:

A) more soil and plants
B) darker lava color
C) a more prominent central crater

Question 55

When basaltic lava reach the ocean they:

A) cause lava fountains at the vent on land
B) form pillow basalts
C) can flow long distances on top of the water
D) form circular calderas
E) all of these

Question 56

What type of basaltic feature is shown in this photograph?

A) vesicles
B) volcanic bomb
C) aa lava flow
D) pahoehoe lava flow
E) pyroclastic flow

Question 57

What type of volcanic eruption is probably shown in this photograph?

A) pyroclastic flow
B) fire fountain
C) basaltic lava flow
D) felsic lava flow
E) caldera eruption

Question 58

Scoria cones are composed primarily of:

A) ejected fragments of vesicular lava
B) blocky lava flows and lahar deposits
C) pahoehoe and/or a'a
D) volcanic ash

Question 59

A lava solidifies into nonvesicular basalt instead of vesicular basalt because:

A) the magma has a low content of gas
B) the lava forms a ropy texture
C) the lava flow breaks apart as it flows
D) the lava flow forms lava tubes

Question 60

The higher the gas pressure builds in a magma,:

A) the more explosive an eruptions it is likely to produce
B) the less explosive an eruption is likely to produce
C) the longer the lava flows an eruption will produce
D) the more likely a volcanic done is to form

Question 61

Flood basalt eruptions are fed by:

A) long fissures/dikes
B) lava tubes
C) central vents/craters

Question 62

Which of the following is NOT true about flood basalts?

A) They cover large areas and contain huge volumes of magma.
B) They cover much of the Columbia Plateau of the Pacific Northwest.
C) They are fed from large interconnected composite volcanoes.
D) Some flood basalts erupted at about the same time as major extinctions of species.

Question 63

Which of the following is a hazard but not a risk, according to the textbook?

A) the Kilauea volcano, which covers subdivisions with molten lava
B) a scoria cone that erupts hot molten fragments on an unpopulated Pacific island
C) a volcano in Iceland that threatens people with dangerous gases
D) a volcano in Iceland that caused catastrophic flooding that destroyed houses and roads
E) all of these are both a hazard and a risk

Question 64

Which represents the largest igneous eruptions on Earth?

A) Flood basalts
B) Rhyolite ash columns
C) Curtains of fire

Question 65

What is a main hazard of this type of volcano?

A) hot fragments thrown a short distance from the volcano
B) burning, building collapse, and suffocation from widely distributed pyroclastic material
C) destruction by moderately fluid lava flows that can flow far from the volcano
D) volcanic mudflows and landslides
E) relatively small pyroclastic eruptions caused by localized explosions or collapse

Question 66

Which of the following are hypothesized sources of the magma that produces flood eruptions?

A) Melted lithosphere over a mantle plume
B) Melted asthenosphere from around the plume in the shallow mantle
C) Plume material from deep in the mantle that melts at shallow depths
D) All of these

Question 67

Shield volcanoes have low slopes primarily because:

A) the low viscosity of basaltic magma allows it to flow downhill for long distances
B) they never erupt from the same place twice
C) their abundant ash layers spread out large distances

Question 68

Shield volcanoes, like Mauna Loa, have what kind of slopes?

A) broad, gentle
B) nearly level
C) extremely steep

Question 69

What is a main hazard of this type of volcano?

A) hot fragments thrown a short distance from the volcano
B) burning, building collapse, and suffocation from widely distributed pyroclastic material
C) destruction by viscous lava flows that can flow far from the volcano
D) volcanic mudflows and landslides
E) relatively small pyroclastic eruptions caused by localized explosions or collapse

Question 70

What is the interpreted origin for magma that forms flood basalts?

A) rapid subduction over tens of millions of years
B) rapid seafloor spreading that forms pillow basalts
C) a rising mantle plume
D) flood waters from melting glaciers
E) none of these

Question 71

Shield volcanoes are composed primarily of:

A) basalt lava flows
B) andesite lava flows
C) rhyolite lava flows

Question 72

What are some factors that could allow flood basalts to have high-volume eruptions?

A) a large amount of magma is generated in the mantle
B) magma rises to the surface along thick dikes
C) the magma is hot and has a low viscosity
D) all of these

Question 73

Shield volcanoes are built up primarily by relatively:

A) nonexplosive outpourings of lava
B) explosive ash-forming eruptions
C) high-viscosity dome-forming eruptions

Question 74

Which of the following is NOT true about shield volcanoes in the landscape?

A) They are large mountains with steep slopes.
B) They can construct some of the world's largest volcanoes.
C) They can be large or small.
D) All of these.

Question 75

Which of the following are locations where flood basalts are known to have occurred?

A) Siberia
B) Brazil
C) India
D) Ocean plateaus
E) All of these

Question 76

The largest volcanic eruptions on Earth are floods of:

A) basalt magma
B) rhyolite magma
C) andesite magma

Question 77

Which of the following is a location in which flood basalts erupted?

A) Columbia Plateau
B) Texas Gulf Coast
C) Hawaii

Question 78

When lava flows reach the ocean, they:

A) solidify and add land to an island
B) explode and produce layers of ash
C) form tubes and continue flowing down to the deepest seafloor

Question 79

Flood basalts influence life on Earth because:

A) Large volumes of flood basalts are erupted during a short time
B) Eruptions can release large amounts of gas that cool the atmosphere
C) Eruptions can release large amounts of gas that warm the atmosphere
D) All of these

Question 80

According to the fossil record, what events have coincided with the approximate times when flood basalts were erupting?

A) mass extinction
B) increased diversity of life
C) climate stability and flourishing of life