Deck 6: Volcanoes and Volcanic Hazards

Question 1

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

Answer 1

D

Question 2

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

Answer 2

C

Question 3

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.

Answer 3

C

Question 4

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 5

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 6

Which of the following volcanoes is generally the largest?

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

Question 7

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

Question 8

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 9

What type of eruption is shown in this photograph?

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

Question 10

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

Question 11

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 12

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 13

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 14

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 15

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 16

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 17

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 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

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 20

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 21

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 22

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 23

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 24

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 25

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 26

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 27

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 28

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 29

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 30

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 31

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 32

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 33

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 34

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 35

Shield volcanoes commonly involve:

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

Question 36

Shield volcanoes commonly have:

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

Question 37

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 38

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 39

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 40

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 41

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 42

What type of material likely composes this volcano?

A)felsic to intermediate lava flows
B)pyroclastic flows
C)volcanic mudflows and landslides
D)all of these

Question 43

What type of eruption formed the volcano in this photograph?

A)fluid lava flows
B)viscous lava and pyroclastic eruptions
C)lava fountains
D)fissure eruptions
E)eruptions beneath the seafloor

Question 44

Composite volcanoes are so called because they:

A)are a combination of shield volcanoes,scoria cones,and other volcanoes
B)have many different types of geologic hazards
C)were first discovered on the island of Composita in Italy
D)are composed of lava flows,pyroclastic material,and mudflows
E)none of these

Question 45

Which of the numbered features is a lahar?

A)1
B)2
C)3
D)4
E)5

Question 46

Which of the numbered features is a pyroclastic column?

A)1
B)2
C)3
D)4
E)5

Question 47

The classic volcano shape is displayed by:

A)a composite volcano
B)a caldera
C)a fissure eruption
D)pillow basalts

Question 48

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 49

Hazards associated with basaltic lava flows and eruptions are:

A)burial of roads and neighborhoods by lava flows
B)house fires
C)floods from catastrophic melting of ice
D)all of these

Question 50

What types of rocks would be most common in a composite volcano?

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

Question 51

Which of the following are hazards associated with scoria cones?

A)volcanic bombs and other large projectiles ejected from the volcano
B)toxic gases
C)fine particles of volcanic ash
D)all of these

Question 52

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

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

Question 53

Which of the following is NOT a typical match between the type of eruption and resulting rock type?

A)lava from a composite volcano-andesite
B)eruption column-tephra
C)pyroclastic flow-scoria
D)volcanic-derived mudflow-breccia with angular fragments

Question 54

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 55

Which of the numbered features is a lava flow?

A)1
B)2
C)3
D)4
E)5

Question 56

Which of the numbered features is a pyroclastic flow?

A)1
B)2
C)3
D)4
E)5

Question 57

What types of rocks would be common in a composite volcano?

A)felsic and intermediate lava flows
B)pyroclastic rocks from an eruption column
C)pyroclastic rocks from pyroclastic flows
D)rocks with fragments formed by landslides and mudflows
E)all of these

Question 58

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 59

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 60

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 61

What are the rounded hills inside the Valles Caldera?

A)volcanic necks
B)landslides
C)volcanic domes
D)scoria cones

Question 62

Volcanic domes commonly are partially destroyed when:

A)gases are released slowly out the top of the dome,dissolving it
B)steep parts of the dome collapse and cause small pyroclastic flows
C)fast-moving,low-viscosity lava carries away part of the dome
D)the center of the dome collapses,forming a composite volcano
E)all of these

Question 63

What type of eruption formed this flow-banded rhyolite?

A)a viscous lava flow
B)a pyroclastic column
C)a pyroclastic flow
D)a lava that broke apart while it flowed
E)a lava fountain

Question 64

What type of eruption 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 65

What was the most damaging type of eruption that occurred at Vesuvius in Italy?

A)A huge landslide caused a lateral blast that knocked down trees and buildings.
B)A fast-moving viscous lava flow flowed through the middle of Pompeii.
C)The volcano was so heavy that it caused part of the island to collapse.
D)One or more pyroclastic flows hit the city of Pompeii.
E)None of these.

Question 66

Which of the following rock types is NOT characteristic of volcanic domes?

A)glassy volcanic rocks that are unstable over time
B)vesicular basalt with very large holes from dangerous gas
C)volcanic breccia formed by fracturing of the outer part of the dome
D)mixtures of pieces of the dome and ash from dome collapse

Question 67

What is a main hazard of this type of volcano?

A)hot molten fragments thrown a short distance from the volcano
B)viscous lava that moves too fast for people to outrun
C)destruction by moderately fluid lava flows that can flow far from the volcano
D)relatively small pyroclastic eruptions caused by localized explosions or collapse

Question 68

What type of eruption formed this unit composed of volcanic blocks and volcanic ash?

A)a fluid basaltic flow
B)a pyroclastic eruption
C)a pahoehoe lava flow
D)a lava fountain

Question 69

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

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

Question 70

The main cause of caldera collapse is:

A)a fissure eruption that allows the shield volcano to split into two or more parts
B)collapse of the north flank by landslides
C)removal of magmas that form pillow basalt
D)collapse of the roof of a magma chamber as magma erupts
E)all of these

Question 71

Which of the following hazards is probably NOT associated with this volcano?

A)destruction by fast-moving lava
B)pyroclastic flows
C)eruption column
D)mudflows
E)collapse of a volcanic dome

Question 72

The most damaging type of eruption that occurred at Mount Pelée,Martinique was:

A)A huge landslide caused a lateral blast that knocked down trees and buildings.
B)A fast-moving viscous lava flow flowed through the middle of St.Pierre.
C)The volcano was so heavy that it caused part of the island to collapse.
D)One or more pyroclastic flows hit the city of St.Pierre.
E)None of these.

Question 73

What is a common hazard of this type of volcano?

A)burning,building collapse,and suffocation from an eruption column and pyroclastic flows
B)volcanic mudflows and landslides
C)relatively small pyroclastic eruptions caused by localized explosions or collapse
D)all of these

Question 74

The eruption that occurred on Mount St.Helens was triggered by:

A)A huge landslide caused a lateral blast that knocked down trees and buildings.
B)A fast-moving viscous lava flow flowed through the middle of Portland.
C)A volcano that was so heavy that it caused part of the island to collapse.
D)A scoria cone that sent up a large column of pyroclastic material.
E)None of these.

Question 75

The most dangerous type of volcano is a:

A)scoria cone
B)scoria cone whose magmas are interacting with groundwater
C)huge shield volcano
D)composite volcano

Question 76

Which of the following are dangerous aspects of composite volcanoes?

A)pyroclastic flows
B)landslides and mudflows
C)an eruption column
D)all of these

Question 77

What type of eruption formed this flow-banded obsidian?

A)a viscous lava flow
B)a pyroclastic column
C)a pyroclastic flow
D)a lava that broke apart while it flowed
E)a lava fountain

Question 78

Which of the following is NOT a characteristic of a volcanic dome?

A)the outer part of the dome contains blocks and other rubble
B)some parts contain volcanic glass,such as obsidian
C)they are one of the largest types of volcanoes
D)many domes are associated with composite volcanoes and calderas

Question 79

Which of the following was common to the eruptions of Vesuvius,Mount Pelée and Mount St.Helens?

A)they are all composite volcanoes
B)earthquakes before the eruption
C)small eruptions of tephra
D)pyroclastic flows
E)all of these

Question 80

What type of eruption formed this felsic volcanic breccia?

A)a pahoehoe lava flow
B)a pyroclastic column
C)a pyroclastic flow
D)a lava that broke apart while it flowed
E)a lava fountain