Deck 4: Volcanoes and Volcanic Processes

Question 1

Which type of mafic flow has a rough, jagged, clinkery surface and advances slowly at speeds less than 50 m/hour?

A)aa
B)block and ash flow
C)pahoehoe
D)scoria

Answer 1

A

Question 2

Which magma association with the volcanic landform is false?

A)cinder cones - mafic
B)composite volcanoes - andesitic
C)glassy volcanic domes - felsic
D)volcanic plateaus and shields - felsic

Answer 2

D

Question 3

At the same temperature, why are magmas with high silica contents more viscous?

A)Because high viscosity magma will flow more readily and rhyolites flow the farthest.
B)They are more linked together in chains and nets that are strong enough to resist flow.
C)Any magma with more than 50% silica content is too sticky to flow.
D)The magmas with high silica content are also richer in iron and too dense to flow.

Answer 3

B

Question 4

Which was the most powerful, explosive volcanic eruption of historic time?

A)Mt.Pele, Martinique, 1902
B)Vesuvius, Italy, 79 A.D.
C)Tambora, Indonesia, 1815
D)Nevado del Ruiz, Columbia, 1985

Question 5

In November 2010, which Indonesian volcano provided the largest eruption in SE Asia in a century?

A)Mt.Pinatubo, Phillipines
B)Kilauea, Hawaii
C)Mount Merapi, Java
D)Mt.Etna, Italy

Question 6

What kind of material is most commonly added to the landscape in explosive volcanic eruptions?

A)thin fluid mafic flows that can travel 10's of kilometers
B)volcanic gases and fumarolic deposits
C)pyroclastics, ash, bombs, and broken rock
D)volcanic plugs that form inside craters

Question 7

Approximately how long has B.C.'s Mt.Garibaldi, in the Canadian part of the Cascades volcanoes, been dormant?

A)since May 1980
B)since 1967
C)since 1912
D)since the last Ice Age

Question 8

Which of the following is a major dissolved volatile constituent in both magmas and volcanic gases?

A)water
B)carbon monoxide
C)hydrogen chloride
D)methane

Question 9

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

A)felsic, andesitic, mafic
B)andesitic, felsic, mafic
C)mafic, felsic, andesitic
D)mafic, andesitic, felsic

Question 10

Which one of the following statements is false?

A)Melting temperatures of silicate rocks increase with increased pressure.
B)Melting temperatures of silicate rocks are lowered by small amounts of water.
C)Mafic magmas in general have higher temperatures than felsic magmas.
D)When magma reaches the surface, its dissolved gas content increases.

Question 11

In general, which of the following types of magma will be more likely to erupt explosively?

A)a highly viscous felsic magma
B)a relatively low viscosity mafic magma
C)an intermediate andesitic magma with a low water content
D)a very fluid komatiitic magma

Question 12

How fast do hot fluid basalt flows typically advance?

A)< 5 m/hour
B)10 to 300 m/hour
C)> 30 km/hour
D)> 100 m/second

Question 13

Which type of mafic lava flow has a fairly smooth, flow folded, ropy surface?

A)aa
B)block and ash flow
C)pahoehoe
D)scoria

Question 14

What drives explosive volcanic eruptions?

A)andesitic magma's extremely low viscosity
B)collapsing eruption columns
C)expanding superheated volcanic gases
D)high pressures from the melting region far beneath the volcano

Question 15

What are the two varieties of basaltic lava flows?

A)aa, pahoehoe
B)cinders, pumice
C)bombs, blocks
D)tuff, breccia

Question 16

Which statement about the November 2010 eruption of Mount Merapi is false?

A)The eruption could be heard 20 kilometres away.
B)Plumes of ash rose high into the atmosphere and darkened the sky.
C)Mudflows (lahars)accompanied the major eruptive events.
D)The event burned homes and killed people and cattle.

Question 17

How far did erupted materials travel and effect cars and trees during the last major eruption of Mount Merapi?

A)240 kilometres away from the volcano
B)12,000 metres into the Stratosphere
C)approximately 1200 kilometres into India and Nepal
D)around the world for several days

Question 18

What is the largest immediate volcanic threat to human life and property?

A)incandescent lava fountains and lava flows like at Kilauea since 1983
B)proximity on the ground to explosive eruptions like Mount Merapi, Pinatubo, and Nevado de Ruiz
C)stratospheric ash clouds that pose a hazard to international airline travel
D)being encased in plaster like the former victims of Pompeii

Question 19

Which two factors 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 20

What is the direct control on whether a volcano will erupt violently or quietly send out a few flows?

A)the composition of the magma, its temperature, and dissolved gas content
B)the duration of the quiet interval since its last violent eruption
C)what the total volume of the volcano has at the time of eruption
D)the population density

Question 21

Oxidized, reddish, vesicle rich, mafic lapilli that pile up to form cinder cones are called ________.

A)blocks
B)bombs
C)pumice
D)scoria

Question 22

Which are usually the most abundant gases emitted during mafic volcanism?

A)chlorine and sodium
B)neon and ammonia
C)oxygen and nitrogen
D)water and carbon dioxide

Question 23

How are volcanic conduits formed?

A)by injecting molten magma up through the volcano to clear a path
B)by erosion from hot gases that carry hard abrasive rocks and ash upwards
C)by superheated gases melting a pipe through the older rocks of the volcano
D)The vent is kept clear by continuous eruption and the walls are formed by deposits.

Question 24

Which statement is most correct concerning volcanic effects on our atmosphere?

A)Active volcanism is responsible for maintaining atmospheric levels of nitrogen.
B)Gases from volcanoes condense to make natural fertilizer, boosting plant growth.
C)If it were not for active volcanism there would be no free oxygen in the atmosphere.
D)Pollution of the atmosphere by sulfur compounds contributes significantly to acid rain.

Question 25

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 26

Volcanic lapilli are particles ________.

A)of fused flattened silica rich glass shards and stretched out gas bubbles
B)also called cinders, the size of small stones, 2 to 64 millimetres across
C)angular rock fragments larger than 64 millimetres
D)of incandescent lava that attain aerodynamic shapes and weigh up to 200 tons

Question 27

What volcanoes dominate in the Galapagos, Iceland, and Kenya?

A)composite volcano
B)shield
C)cinder cones
D)stratospheric

Question 28

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

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

Question 29

What volcanic environment generated both Mt.Pelee and Montserrat?

A)the Lesser Antilles arc
B)the Italian flood basalt province
C)the Mid-Atlantic Ridge
D)the Andes arc

Question 30

What are massive, gently sloping volcanoes built of successive, mafic lava flows?

A)shield
B)composite volcanoes
C)cinder cones
D)stratospheric

Question 31

How do volcanic bombs originate?

A)as high temperature residue violently expelled from the melting region, all the way up the volcanic conduit
B)as blocks of old shattered volcanic rock ejected from an erupting volcanic crater
C)as semi-molten magma blobs that get erupted, streamlined, and 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 32

The 1991 Pinatubo eruption in the Philippines caused global temperatures to drop over the next year.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 froze as they decayed.
D)Sulfur dioxide was released and formed aerosols in the atmosphere.

Question 33

What destroyed the city of St.Pierre, Martinique in 1902?

A)mudflows
B)mafic lava flows
C)heavy ashfall
D)a nuée ardente

Question 34

Which volcano is a very large, gently sloping mound composed mainly of mafic lava flows?

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

Question 35

Kilauea and Mauna Loa are what kind of volcanoes?

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

Question 36

Which natural phenomenon occurs for several years after major explosive volcanic eruptions such as Tambora and Krakatoa?

A)heavy falls of volcanic ash within 100 kilometres of the volcano
B)unusually warm weather in the tropics and subtropics
C)a worldwide rise in sea level of one to three centimetres
D)volcanic gases linger in the atmosphere

Question 37

How far can nueés ardentes travel from their source vents?

A)< 1 kilometre
B)up to 10 kilometres
C)> 100 kilometres
D)> 1000 kilometres

Question 38

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 39

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 40

Which one of the following is made of abundant pyroclastic materials?

A)rhyolite dome
B)basaltic shield volcano
C)composite volcano or stratovolcano
D)fissure-related flood basalts

Question 41

What kind of volcano is Mount Garibaldi?

A)a basaltic cinder cone
B)a composite volcano
C)a basaltic shield volcano
D)a small, welded tuff cone

Question 42

How quickly are volcanoes like Paricutin in Mexico or Mt.Edziza in central B.C.built?

A)in a single eruption within a few hours
B)in a single eruption within a few days
C)in a single eruptive cycle lasting about a year or more
D)in several eruptive cycles over 10's of thousands of years

Question 43

What natural disaster contributed to the disappearance of the Minoan civilization and gave rise to the legend of The Lost Island of Atlantis mentioned in Plato's writings?

A)It washed away in a giant tsunami about 79 C.E.
B)It was obliterated by volcanic dust storms from North Africa in the sixth century C.E.
C)It was buried by thick ash deposits from Mt.Vesuvius in 79 B.C.E.
D)It was buried by thick ash deposits from the volcanic eruption of Thera about 1600 B.C.E.and sank as the caldera beneath the island collapsed.

Question 44

The average composition of rocks composing a large composite volcano is similar to which magma?

A)mafic
B)ultramafic
C)andesitic
D)felsic

Question 45

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

A)composite volcanoes
B)shield
C)cinder cones
D)stratospheric

Question 46

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 volcanoes
D)lava flows from a large cinder cone complex

Question 47

The 1943-44 eruption of Paricutin in Mexico was characterized by which one of the following sets of volcanic phenomena?

A)mudflows; explosive ash eruptions
B)welded-tuff deposition; caldera formation
C)cinder cone building; mafic aa lava
D)pyroclastic eruptions; nuée ardente flows

Question 48

Which one of the following best describes volcanism in the Cascade Range of northern California through Washington and its northerly extension as the Garibaldi Belt in SW B.C.?

A)related to a mantle plume
B)related to plate subduction
C)related to a mid-ocean ridge system
D)related to deep, transform faults

Question 49

What are small basaltic cones built during one short, eruptive episode?

A)cinder cones
B)shield volcanoes
C)composite volcanoes
D)stratospheric

Question 50

Which of the following statements concerning cinder cones is false?

A)They are small volcanoes with fairly steep sides but large central craters.
B)They are built mostly or entirely during one eruptive cycle.
C)The cinders and other pyroclastic particles are consolidated into welded tuff.
D)They are often asymmetric with the higher rim in the downwind direction.

Question 51

For the following items, please choose from one of the following answers.
A.shield volcanoes B.composite/stratovolcanoes C.cinder cones
________ large, fairly steep-sided cones composed of lavas and pyroclastic layers

Question 52

For the following items, please choose from one of the following answers.
A.shield volcanoes B.composite/stratovolcanoes C.cinder cones
________ small basaltic cones built during one, short, eruptive episode

Question 53

Gas rich andesitic magmas generate composite volcanoes made up of ________.

A)abundant basalt dykes and thick accumulations of low viscosity flows
B)conical shaped lava flows
C)abundant coarse pyroclastics and short, thick, viscous lava flows
D)multiple overlapping rhyolite domes rimming a central caldera

Question 54

Which best describes a caldera?

A)a small, steep-sided, volcanic depression bored out by an eruptive plume
B)a large circular volcanic depression caused by collapse after a large scale, explosive felsic eruption
C)a collapse pit less than 1 square kilometre on the summit of a volcano
D)a large depression hundreds of kilometres across full of volcanic deposits

Question 55

For the following items, please choose from one of the following answers.
A.shield volcanoes B.composite/stratovolcanoes C.cinder cones
________ the big volcanoes of Hawaii

Question 56

What type are the volcanoes of the Cascades and Alaska's Aleutian Islands?

A)composite volcanoes
B)shield
C)cinder cones
D)stratospheric

Question 57

For the following items, please choose from one of the following answers.
A.shield volcanoes B.composite/stratovolcanoes C.cinder cones
________ the volcanoes of southwestern Alaska and the Aleutian Islands

Question 58

For the following items, please choose from one of the following answers.
A.shield volcanoes B.composite/stratovolcanoes C.cinder cones
________ massive, gently sloping volcanoes built of successive, basaltic lava flows

Question 59

What volcanoes have the highest elevations?

A)composite volcanoes
B)shield
C)cinder cones
D)stratospheric

Question 60

Which correctly describes the size and thickness variation in pyroclastics relative to the composite volcano they came from?

A)Size and thickness both decrease uniformly away from the central vent.
B)Size increases then decreases with distance, but deposits are the same thickness.
C)Size increases, and the deposits get thicker away from the vent.
D)Size decreases, but deposits thicken downslope and then thin with distance.

Question 61

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

A)explosive; composite volcanoes
B)submarine; mafic lava flows
C)subversive fissure eruptions and flood basalts
D)explosive; felsic, pyroclastic flows

Question 62

A magma's viscosity and tendency to cause explosive eruptions depends on its composition, temperature, and volatile gas content.

Question 63

Which statement best describes the big Hawaiian volcanoes?

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

Question 64

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

A)A powerful explosion blew away the top of a composite volcano; 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 pyrodastic-flow eruptions; 7700 years ago.

Question 65

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

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

Question 66

What is the most abundant type of magma erupted at oceanic spreading centres?

A)mafic
B)pyroclastic
C)andesitic
D)felsic

Question 67

Which of the following is associated with deep mantle plumes?

A)Vesuvius and the other volcanoes of Italy
B)the volcanoes of Hawaii and the thermal 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 68

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

Question 69

The Columbia Plateau in Washington and Oregon is what type of volcanic feature?

A)flood basalt plateau
B)a thick stack of welded-luff layers
C)a caldera filled with rhyolite lava flows
D)a field of large composite volcanoes

Question 70

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, mantle plume volcanism

Question 71

How are the Icelandic volcanoes related to plate tectonics?

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

Question 72

Which region has the greatest concentration of currently active volcanoes?

A)Pacific "Ring of Fire"
B)coastal plain of west Africa
C)Siberia
D)Red Sea area

Question 73

The eruptions of the Hawaiian volcanoes may be described as explosive in comparison to the 2010 Mount Merapi eruption.

Question 74

The greatest rate of volcanism and largest accumulations of volcanic deposits are associated with ________.

A)ash clouds dispersed in the stratosphere
B)flood basalts from fissure eruptions
C)giant cinder cones
D)rhyolitic lava domes

Question 75

What is the dominant lava type erupted along mid-ocean ridges?

A)mafic
B)felsic
C)andesitic
D)ultramafic

Question 76

How was Crater Lake, Oregon formed?

A)a prehistoric eruption of Mount St.Helens
B)caldera collapse of the top of Mt.Mazama after the eruption 7700 years ago partly emptied the magma chamber
C)when sea floor spreading permitted seawater to flood into the newly formed volcanic rift
D)as a remnant of the "great flood"

Question 77

What is the correct environment for the geologically recent, volcanic activity in the Yellowstone National Park area?

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

Question 78

Which of the following best describes seamounts and islands of the deep ocean basins?

A)huge granite batholiths intruded beneath the ocean floor
B)piles of basaltic lava flows built up from the ocean floor by multiple summit and flank eruptions
C)andesitic pyroclastic rocks submerged when the mountains sank below sea level
D)domed gabbro intrusions and massive, submarine, rhyolitic, pyroclastic cones

Question 79

In general, mafic magmas are more likely than andesitic to erupt explosively.

Question 80

Which of the following best describes Black Tusk, a volcanic feature in British Columbia?

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