Question 1

Which of the following is true concerning the 1980 eruption of Mt.St.Helens?

Accepted Answer

A)  The eruption was a complete surprise to geologists and provided no forewarning.
B)  The eruption produced the largest basalt flow of the 20th century anywhere on Earth.
C)  The eruption began with a lateral blast of debris that was ejected at the speed of sound.
D)  No lahars were produced because the eruption occurred in the winter.

Question 2

Which of the following is NOT true? Hot-spot volcanoes ________.

Accepted Answer

A)  can arise from the ocean floor
B)  can arise on continents
C)  can arise in the interior of lithospheric plates
D)  always produce mafic lava flows

Question 3

Rhyolitic lavas ________.

Accepted Answer

A)  do not flow as far from the vent as basaltic lavas do
B)  are commonly found at oceanic hot spots
C)  are associated with volcanoes that almost never emit pyroclastic debris
D)  are commonly found on shield volcanoes

Question 4

The Columbia River Plateau is an example of a ________.

Accepted Answer

A)  caldera
B)  fissure
C)  flood basalt
D)  hot spot

Question 5

Based on your knowledge of volcanoes and volcanic products,you can say with confidence that the outcrop in the image below ________.

Accepted Answer

A)  formed on land at a continental hotspot
B)  formed underwater at a subduction zone
C)  formed on land at a continental rift
D)  formed underwater at a mid-ocean ridge

Question 6

The difference between tephra and tuff is that ________.

Accepted Answer

A)  tephra is created in ash falls,whereas tuff is created in pyroclastic flows
B)  tephra is unlithified,whereas tuff is lithified
C)  tephra is always felsic to intermediate,whereas tuff is always mafic
D)  tephra is formed at stratovolcanoes while tuffs are formed at cinder cones

Question 7

Which of the following poses the greatest hazard to human life associated with volcanoes?

Accepted Answer

A)  flowing lava
B)  volcanic gas
C)  falling ash
D)  pyroclastic flows

Question 8

The Hawaiian island chain is an example of a(n) ________.

Accepted Answer

A)  island volcanic arc
B)  continental volcanic arc
C)  hot-spot island chain
D)  stratovolcanic assembly

Question 9

The lithification of material from a pyroclastic flow forms a rock called ________.

Accepted Answer

A)  tephra
B)  ignimbrite
C)  lapilli
D)  air-fall tuff

Question 10

Gases that are abundantly emitted by volcanoes include ________.

Accepted Answer

A)  water vapor,carbon dioxide,and sulfur dioxide
B)  oxygen,ozone,and water vapor
C)  oxygen,hydrogen,and argon
D)  carbon dioxide,carbon monoxide,and oxygen

Question 11

The image below shows a lava dome that never left the volcanic crater.What is the likely composition of the rocks that make up this lava dome?

Accepted Answer

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

Question 12

Volcanoes have provided some positive benefits to humankind and life in general over geologic time.Which of the following is NOT true about volcanoes?

Accepted Answer

A)  Volcanic eruptions can enrich soils,making land more fertile.
B)  Volatiles from volcanoes provided much of our early oceans' water.
C)  Volcanic eruptions have prevented several mass extinctions by cooling Earth's climate.
D)  Gasses from volcanic eruptions provided much of the content of the early atmosphere.

Question 13

Pele's hair ________.

Accepted Answer

A)  consists of thin strands of basaltic glass
B)  acquires aerodynamic torpedo-like shapes during flight out of the volcanic vent
C)  forms only at the leading edge of basaltic lava flows
D)  forms when volcanic ash erupts into a rain cloud

Question 14

Scientists monitor volcanoes to help predict when eruptions will occur.Which of the following is NOT a potential sign to look for when predicting volcanic eruptions?

Accepted Answer

A)  changes in earthquake activity
B)  changes in Earth's magnetic field
C)  small changes in the shape of the volcano
D)  increases in gas and steam emissions

Question 15

Compared to felsic lavas,mafic lavas have a ________.

Accepted Answer

A)  lighter color
B)  lower viscosity
C)  lower density
D)  higher silica content

Question 16

Phreatic eruptions take place when ________.

Accepted Answer

A)  volatiles effervesce prior to lava flow
B)  groundwater interacts with magma
C)  basaltic lava clogs the eruptive vent
D)  lava or pyroclastic debris erupts by bursting through the sides of the volcano

Question 17

Olympus Mons,the largest known volcano in our Solar System,is an example of a ________.

Accepted Answer

A)  stratovolcano
B)  cinder cone
C)  shield volcano
D)  fissure volcano

Question 18

Volcanic bombs are ________.

Accepted Answer

A)  volcanic fragments that were ejected while still soft or molten
B)  explosive bodies of lava with high volatile content
C)  volcanic fragments that were already solid rock before being ejected during an eruption
D)  used by geologists to set off small eruptions in volcanoes that are deemed potentially dangerous

Question 19

Nonviolent eruptions characterized by extensive flows of basaltic lava are termed ________.

Accepted Answer

A)  pyroclastic
B)  effusive
C)  explosive
D)  plinian

Question 20

Of the three primary forms of subaerial volcanoes,________ consist of a simple pile of tephra often formed in a single eruption.

Accepted Answer

A)  stratovolcanoes
B)  cinder cones
C)  shield volcanoes
D)  fissure volcanoes

Exam 9: The Wrath of Vulcan: Volcanic Eruptions

Of the three primary forms of subaerial volcanoes,________ consist of a simple pile of tephra often formed in a single eruption.

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Volcanic bombs are ________.

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Which of the following is NOT true? Hot-spot volcanoes ________.

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Phreatic eruptions take place when ________.

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Gases that are abundantly emitted by volcanoes include ________.

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Compared to felsic lavas,mafic lavas have a ________.

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The image below shows a lava dome that never left the volcanic crater.What is the likely composition of the rocks that make up this lava dome?

Correct AnswerverifiedShow Answer

Nonviolent eruptions characterized by extensive flows of basaltic lava are termed ________.

Correct AnswerverifiedShow Answer

Pele's hair ________.

Correct AnswerverifiedShow Answer

Volcanoes have provided some positive benefits to humankind and life in general over geologic time.Which of the following is NOT true about volcanoes?

Correct AnswerverifiedShow Answer

Which of the following poses the greatest hazard to human life associated with volcanoes?

Correct AnswerverifiedShow Answer

The Columbia River Plateau is an example of a ________.

Correct AnswerverifiedShow Answer

The lithification of material from a pyroclastic flow forms a rock called ________.

Correct AnswerverifiedShow Answer

Rhyolitic lavas ________.

Correct AnswerverifiedShow Answer

The Hawaiian island chain is an example of a(n) ________.

Correct AnswerverifiedShow Answer

The difference between tephra and tuff is that ________.

Correct AnswerverifiedShow Answer

Based on your knowledge of volcanoes and volcanic products,you can say with confidence that the outcrop in the image below ________.

Correct AnswerverifiedShow Answer

Which of the following is true concerning the 1980 eruption of Mt.St.Helens?

Correct AnswerverifiedShow Answer

Scientists monitor volcanoes to help predict when eruptions will occur.Which of the following is NOT a potential sign to look for when predicting volcanic eruptions?

Correct AnswerverifiedShow Answer

Olympus Mons,the largest known volcano in our Solar System,is an example of a ________.

Correct AnswerverifiedShow Answer

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