Deck 9: Volcanoes and Other Igneous Activity

Question 1

________ magma is the most abundant type erupted at oceanic spreading centers.

A) Basaltic
B) Granitic
C) Andesitic
D) Pegmatitic

Answer 1

A

Question 2

In 1980, ________ was the first Cascade Range volcano to erupt since Mt. Lassen in 1915-16.

A) Mt. Rainier
B) Mt. Shasta
C) Kilauea
D) Mt. St. Helens

Answer 2

D

Question 3

________ are usually the most abundant gases emitted during basaltic volcanism.

A) Chlorine and sodium
B) Neon and ammonia
C) Oxygen and nitrogen
D) Water and carbon dioxide

Answer 3

D

Question 4

the volcanoes of southwestern Alaska and the Aleutian Islands

Question 5

Which of the following is associated with deep mantle hot spots?

A) Vesuvius and the other volcanoes of Italy
B) the volcanoes of Hawaii and Quaternary activity in Yellowstone National Park
C) the very young cinder cones scattered across the southwestern United States
D) Mt. St. Helens and other volcanoes of the Cascade Mountains

Question 6

________ is a major dissolved volatile constituent in both magmas and volcanic gases.

A) Water
B) Carbon monoxide
C) Hydrogen chloride
D) Methane

Question 7

Mount Pelée on Martinique is an example of a ________.

A) shield volcano
B) cinder cone
C) lava dome
D) composite volcano

Question 8

Which of the following factors help determine whether a volcanic eruption will be violent or relatively quiescent?

A) amount of dissolved gas in the magma
B) temperature of the magma
C) composition of the magma
D) all of these

Question 9

Paricutin is an example of a ________.

A) shield volcano
B) cinder cone
C) lava dome
D) composite volcano

Question 10

Cinder cones ________.

A) have very steep slopes
B) are usually less than 300 meters (1000 feet) high
C) consist largely of pyroclastics
D) all of these

Question 11

Kilauea is an example of a ________.

A) shield volcano
B) cinder cone
C) lava dome
D) volcanic neck

Question 12

massive, gently sloping volcanoes built of successive, basaltic lava flows

Question 13

The ________ ocean basin is rimmed by the most subduction zones.

A) Atlantic
B) Indian
C) Pacific
D) Arctic

Question 14

The 1991 Pinatubo eruption in the Philippines caused brilliantly colored sunrises and sunsets to be seen for the next few years. What caused this phenomenon?

A) The eruption added large amounts of carbon dioxide to the atmosphere.
B) The eruptive cloud destroyed parts of the Earth's protective ozone layer.
C) Radioactive atoms blown into the atmosphere glowed red as they decayed.
D) Sulfur dioxide and other erupted gases formed aerosols in the stratosphere.

Question 15

large, fairly steep-sided cones composed of lavas and pyroclastic layers

Question 16

Which type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface?

A) aa
B) pegmatitic
C) pahoehoe
D) scoria

Question 17

The Columbia Plateau in the northwestern United States is an excellent example of ________.

A) silica-rich lava flows
B) pyroclastic flow deposits
C) flood basalts
D) an eroded shield volcano

Question 18

The most violent volcanic activity is associated with ________.

A) fissure eruptions
B) shield volcanoes
C) cinder cones
D) composite cones

Question 19

small basaltic cones built during one short, eruptive episode

Question 20

Volcanic bombs originate ________.

A) as laser-guided, granite blocks launched from a supersonic jet
B) as blocks of volcanic rock ejected from an erupting volcanic crater
C) as erupted magma blobs that partly congeal before falling to the ground
D) as ash particles that join together in the eruptive plume and fall as cobble-sized objects

Question 21

Which statement about the May, 1980, eruption of Mount St. Helens is false?

A) During the eruptive period, the mountain peak was substantially built up by new lava flows and pyroclastic debris.
B) Plumes of ash rose high into the atmosphere during the major eruptive events.
C) Mudflows accompanied the major eruptive events.
D) The most powerful explosive event was preceded by a massive landslide.

Question 22

Spreading center volcanism most generally produces rocks that are ________.

A) granitic in composition
B) basaltic in composition
C) rhyolitic in composition
D) ultramafic in composition

Question 23

The average composition of rocks comprising a large composite cone or stratovolcano is similar to a(n) ________ magma.

A) basaltic
B) ultramafic
C) andesitic
D) rhyolitic

Question 24

A ________ volcano is a very large, gently sloping mound composed mainly of basaltic lava flows.

A) composite
B) stratospheric
C) cinder cone
D) shield

Question 25

________ tend to increase the explosive potential of a magma body beneath a volcano.

A) High viscosity and dissolved gas
B) High viscosity, low dissolved gas content
C) Low silica content, low viscosity
D) Low viscosity, low dissolved gas content

Question 26

The Icelandic volcanoes are related to plate tectonics because ________.

A) they lie on a spreading center where two plates are converging
B) they lie on a subduction zone where two plates are converging
C) they lie on a spreading center where two plates are moving apart
D) they lie along a subduction zone where two plates are diverging

Question 27

Which region has the greatest concentration of currently active volcanoes?

A) the coastal plain of western Africa
B) European Russia and Siberia
C) the area surrounding the Red Sea
D) the circum-Pacific area

Question 28

The recent (geologically) volcanic activity in Yellowstone National Park is ________.

A) related to plate subduction
B) related to a divergent plate boundary
C) related to a transform plate boundary
D) related to intraplate, hot spot volcanism

Question 29

Mount St. Helens is ________.

A) a basaltic cinder cone
B) an explosive stratovolcano
C) a basaltic shield volcano
D) a small, welded tuff cone

Question 30

Which one of the following statements concerning cinder cones is false?

A) They are small volcanoes with fairly steep sides.
B) They are built mostly or entirely during one eruptive cycle.
C) The cinders and other pyroclastic particles are consolidated into welded tuff.
D) The cinders most commonly are basaltic.

Question 31

Kilauea and Mauna Loa are ________.

A) explosive, rhyolitic volcanoes
B) andesitic stratovolcanoes
C) basaltic shield volcanoes
D) small, basaltic cinder cones

Question 32

The 1943 eruption of Paricutin in Mexico was characterized by ________.

A) mudflows and explosive ash eruptions
B) welded-tuff deposition and caldera formation
C) cinder cone building and basaltic lava
D) pyroclastic eruptions and nueé ardente flows

Question 33

Which of the following best describes Shiprock, a famous volcanic feature in New Mexico?

A) a very recently active, basaltic cinder cone
B) an extinct, highly symmetrical, composite volcanic cone
C) the eroded remains of a volcanic pipe and radiating dikes
D) an extinct, massive, rhyolitic shield volcano

Question 34

Which one of the following statements concerning volcanic blocks and bombs is true?

A) Blocks are broken fragments of solid rocks; bombs have smaller sizes than lapilli.
B) Bombs are guided to Earth by laser beams; blocks fall anywhere.
C) Bombs are ejected as magma lumps; blocks are ejected as solid fragments.
D) Bombs and blocks are both smaller than lapilli and cinders.

Question 35

the big volcanoes of Hawaii

Question 36

________ destroyed the city of St. Pierre, Martinique, in 1902.

A) Mudflows
B) Basaltic lava flows
C) Heavy ashfall
D) A nueé ardente

Question 37

Which kind of volcanism is typical of mid-oceanic ridge systems?

A) explosive; composite cones
B) submarine; basaltic lava flows
C) fissure eruptions; flood basalt fields
D) explosive; rhyolitic, pyroclastic flows

Question 38

Which type of basaltic lava flow has its surface covered with sharp-edged, angular blocks and rubble?

A) scoria
B) pahoehoe
C) pillow lava
D) aa

Question 39

Magma tends to rise toward Earth's surface principally because ________.

A) water is an abundant constituent of magma
B) silica is abundant in magma
C) magma is a fluid
D) rocks become less dense when they melt

Question 40

Which kind of eruptive activity is most likely to be highly explosive?

A) lava flows from a large shield volcano on an oceanic island
B) fissure eruptions feeding lava to flood basalt accumulations
C) eruptions of big, continental margin, composite cones or stratovolcanoes
D) lava flows from a large cinder cone complex

Question 41

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.
A. caldera B. pipe C. crater D. fumarole

Question 42

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.
A. pahoehoe B. aa C. volcanic bomb D. pillow lava

Question 43

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.
A. ash B. crystals C. lapilli D. blocks

Question 44

Most of the active volcanoes on Earth are located in a belt known as the ________.

A) Ring of Fire
B) Gulf Coast Zone
C) Mid-Pacific Ridge
D) Red Sea rift

Question 45

What volcanic events formed Crater Lake, Oregon? When did they take place?

A) A powerful explosion blew away the top of a stratovolcano 10 million years ago.
B) The crater of a large, extinct cinder cone filled with water 5 million years ago.
C) Landslides and volcanic mudflows dammed the Mazama River 500 years ago.
D) Caldera collapse followed major ash and pyroclastic-flow eruptions 6000 years ago.

Question 46

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.
A. silica content B. temperature C. dissolved gases D. pressure

Question 47

Which of the following is NOT considered pyroclastic debris?

A) ash
B) cinders
C) bombs
D) pahoehoe

Question 48

Which of the following best describes the bedrock in the Sierra Nevada Mountains in California?

A) basalt; dikes
B) gabbro; plutoliths
C) andesite; laccoliths
D) granite; batholiths

Question 49

Which of the following statements best describes the big Hawaiian volcanoes?

A) lie directly above a transform plate boundary that cuts deeply into the mantle
B) lie directly above an active subduction zone where the Pacific plate is sinking into the mantle
C) lie along the crest of the East Pacific Rise, a mid-ocean ridge or spreading center
D) are situated in the interior of a large, Pacific plate above a hot spot deep in the mantle

Question 50

Ash and lapilli are different sized pyroclastic particles.

Question 51

A ________ is an intrusive, igneous rock body that is tabular and concordant.

A) laccolith
B) dike
C) pluton
D) sill

Question 52

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.
A. Mt. Vesuvius B. Mt. Mazama C. Mount Pelée D. Kilauea

Question 53

Which one of the following shows the correct order (left to right) of decreasing magma viscosity?

A) rhyolite, andesite, basalt
B) andesite, rhyolite, basalt
C) basalt, rhyolite, andesite
D) basalt, andesite, rhyolite

Question 54

A ________ is the largest discordant body of intrusive, igneous rock.

A) lopolith
B) laccolith
C) pluton
D) batholith

Question 55

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.
A. sill B. batholith C. dike D. laccolith

Question 56

Dissolved gases may comprise up to a few percent by weight of a magma.

Question 57

What is the largest known volcano in the Solar System?

A) Mauna Loa, Hawaii, Earth
B) Mount Olympus, Greece, Earth
C) Mauna Kea, southern hemisphere, Mars
D) Olympus Mons, Mars

Question 58

Which one of the following best describes volcanism in the Cascade Range, northwestern United States?

A) related to a mantle hot spot
B) related to plate subduction
C) related to a mid-oceanic ridge system
D) related to deep, transform faults

Question 59

A ________ is a near surface, intrusive igneous rock body that results from local inflation of a horizontal sill.

A) batholith
B) dike
C) laccolith
D) volcanic neck

Question 60

The largest igneous intrusive body is called a ________.

A) batholith
B) laccolith
C) stock
D) dike

Question 61

Large, volcanic depressions formed by subsidence and collapse are known as ________.

Question 62

Vents that emit only hot gases and vapors are called ________.

Question 63

Crater Lake in Oregon actually occupies a caldera, not a crater.

Question 64

The viscosities of magmas increase with increasing percentages of silica.

Question 65

Which basaltic lava flow has a relatively smooth surface?

Question 66

Small amounts of water can lower partial melting temperatures in silicate rocks.

Question 67

Powerful, explosive, volcanic eruptions can result in climatic cooling for millions of years following the eruption.

Question 68

The active Hawaiian volcanoes are situated directly above a major boundary between two of the Earth's largest tectonic plates.

Question 69

The eruptions of the Hawaiian volcanoes may be described as explosive in comparison to the 1980 Mount St. Helens eruption.

Question 70

Most basaltic magmas are believed to form by partial melting of granite in the lower crust and upper mantle.

Question 71

________ is the most abundant gaseous component dissolved in most magmas.

Question 72

Basaltic lavas are generally hotter and more viscous than andesite lavas.

Question 73

In general, cinder cones are much larger than shield volcanoes.

Question 74

Aa flows are generally thinner and have smoother surfaces than pahoehoe flows.

Question 75

Vents that emit only heated volcanic gases and water are called fumaroles.

Question 76

Composite volcanic cones are also known as ________.

Question 77

What term describes fragmental volcanic material?

Question 78

Repeated eruptions of relatively fluid lava from fissures can eventually cause an area to be covered by flood basalts.

Question 79

Basalt is the most common magma erupted along oceanic rift systems.

Question 80

Magma generation at depth almost always involves partial melting, not complete melting of the source rock.