Question 1

Compared to felsic lavas,mafic lavas have a ________.

Accepted Answer

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

Question 2

The largest known volcanic eruption in the last million years occurred at ________.

Accepted Answer

A)  Toba Volcano (Indonesia) 
B)  Mt.St.Helens (US
A)  
C)  Mt.Pinatubo (the Philippines) 
D)  Yellowstone Caldera (US
A)  
A)  Toba Volcano (Indonesia) 
B)  Mt.St.Helens (US
A)  
C)  Mt.Pinatubo (the Philippines) 
D)  Yellowstone Caldera (US
A)

Question 3

The pillow basalts in the photo below most likely formed ____________.

Accepted Answer

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

Question 4

The difference between accretionary lapilli and pumice lapilli is that ________.

Accepted Answer

A)  accretionary lapilli are always created in ash falls,whereas pumice lapilli are created in pyroclastic flows 
B)  accretionary lapilli are formed when ash mixes with water in the air 
C)  accretionary lapilli are always felsic to intermediate,whereas pumice lapilli are always mafic 
D)  accretionary lapilli are formed at stratovolcanoes,while pumice lapilli are formed at cinder cones 
A)  accretionary lapilli are always created in ash falls,whereas pumice lapilli are created in pyroclastic flows 
B)  accretionary lapilli are formed when ash mixes with water in the air 
C)  accretionary lapilli are always felsic to intermediate,whereas pumice lapilli are always mafic 
D)  accretionary lapilli are formed at stratovolcanoes,while pumice lapilli are formed at cinder cones

Question 5

Volcanism in Iceland is occurring as a result of ________.

Accepted Answer

A)  eruptions along a mid-ocean ridge 
B)  eruptions from an intraplate hot spot 
C)  eruptions from a hot spot that sits astride a mid-ocean ridge 
D)  subduction of an oceanic plate underneath the continental Eurasian Plate 
A)  eruptions along a mid-ocean ridge 
B)  eruptions from an intraplate hot spot 
C)  eruptions from a hot spot that sits astride a mid-ocean ridge 
D)  subduction of an oceanic plate underneath the continental Eurasian Plate

Question 6

Ash,cinders,and blocks are all types of ________.

Accepted Answer

A)  tephra 
B)  lava flows 
C)  eruptive styles 
D)  volcanoes 
A)  tephra 
B)  lava flows 
C)  eruptive styles 
D)  volcanoes

Question 7

The Columbia River Plateau is an example of a ________.

Accepted Answer

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

Question 8

Increases in heat flow,gas emissions and nearby earthquakes are all signs that a volcano _______.

Accepted Answer

A)  is extinct 
B)  may soon erupt 
C)  is dormant 
D)  has erupted in the past 
A)  is extinct 
B)  may soon erupt 
C)  is dormant 
D)  has erupted in the past

Question 9

What magma properties would most likely lead to the formation of a shield volcano?

Accepted Answer

A)  low viscosity and mafic composition 
B)  high viscosity and felsic composition 
C)  any magma composition so long as it contains a large portion of dissolved volatiles 
D)  an intermediate composition magma that encounters seawater in the magma chamber 
A)  low viscosity and mafic composition 
B)  high viscosity and felsic composition 
C)  any magma composition so long as it contains a large portion of dissolved volatiles 
D)  an intermediate composition magma that encounters seawater in the magma chamber

Question 10

The average time between eruptions is called a(n)________

Accepted Answer

A)  recurrence interval 
B)  prediction 
C)  forecast 
D)  assessment 
A)  recurrence interval 
B)  prediction 
C)  forecast 
D)  assessment

Question 11

A map that shows homes,businesses,roads and other infrastructure that lie in the path of potential volcanic hazards is called a ________________.

Accepted Answer

A)  volcanic hazards assessment map 
B)  volcanic volatile emissions map 
C)  lava viscosity map 
D)  seismic hazards map 
A)  volcanic hazards assessment map 
B)  volcanic volatile emissions map 
C)  lava viscosity map 
D)  seismic hazards map

Question 12

What is the fundamental difference between an explosive and an effusive eruption? What variables are important in determining whether a volcano "flows" or "blows"?

Accepted Answer

Eruptive style varies between volcanoes

Question 13

Common volcanic gases include the following:

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. 
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 14

Rhyolite 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 
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 15

Whether an eruption will produce lava flows or pyroclastic debris depends on the viscosity of magma and the _______

Accepted Answer

A)  elevation of the volcano 
B)  age of the magma 
C)  proportion of volatiles within the magma 
D)  depth of the magma chamber 
A)  elevation of the volcano 
B)  age of the magma 
C)  proportion of volatiles within the magma 
D)  depth of the magma chamber

Question 16

Which volcanic hazard poses the greatest threat to humans?

Accepted Answer

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

Question 17

Basaltic lavas ________.

Accepted Answer

A)  have low viscosity and low silica content 
B)  have high viscosity and high silica content 
C)  are more viscous than rhyolitic lavas 
D)  typically contain a greater proportion of trapped volatiles than rhyolitic lavas 
A)  have low viscosity and low silica content 
B)  have high viscosity and high silica content 
C)  are more viscous than rhyolitic lavas 
D)  typically contain a greater proportion of trapped volatiles than rhyolitic lavas

Question 18

The textural term for a basaltic lava flow that has a smooth,ropy appearance is ________.

Accepted Answer

A)  pahoehoe 
B)  a''a' 
C)  pumice 
D)  ignimbrite 
A)  pahoehoe 
B)  a''a' 
C)  pumice 
D)  ignimbrite

Question 19

What is a caldera? How is a caldera different from a stratovolcano?

Accepted Answer

A caldera is a collapse structure that o

Question 20

Volcanism is least likely to occur in which of the following geologic settings?

Accepted Answer

A)  subduction zone 
B)  mid-ocean rift 
C)  passive margin 
D)  oceanic hot spot 
A)  subduction zone 
B)  mid-ocean rift 
C)  passive margin 
D)  oceanic hot spot

Exam 5: The Wrath of Vulcan: Volcanic Eruptions

Compared to felsic lavas,mafic lavas have a ________.

The largest known volcanic eruption in the last million years occurred at ________.

The pillow basalts in the photo below most likely formed ____________.

The difference between accretionary lapilli and pumice lapilli is that ________.

Volcanism in Iceland is occurring as a result of ________.

Ash,cinders,and blocks are all types of ________.

The Columbia River Plateau is an example of a ________.

Increases in heat flow,gas emissions and nearby earthquakes are all signs that a volcano _______.

What magma properties would most likely lead to the formation of a shield volcano?

The average time between eruptions is called a(n)________

A map that shows homes,businesses,roads and other infrastructure that lie in the path of potential volcanic hazards is called a ________________.

What is the fundamental difference between an explosive and an effusive eruption? What variables are important in determining whether a volcano "flows" or "blows"?

Common volcanic gases include the following:

Rhyolite lavas ________.

Whether an eruption will produce lava flows or pyroclastic debris depends on the viscosity of magma and the _______

Which volcanic hazard poses the greatest threat to humans?

Basaltic lavas ________.

The textural term for a basaltic lava flow that has a smooth,ropy appearance is ________.

What is a caldera? How is a caldera different from a stratovolcano?

Volcanism is least likely to occur in which of the following geologic settings?

The Earth in Context

The Way the Earth Works: Plate Tectonics

Patterns in Nature: Minerals

Up From the Inferno: Magma and Igneous Rocks

Pages of the Earths Past: Sedimentary Rocks

Metamorphism: a Process of Change

A Violent Pulse: Earthquakes

Crags,cracks,and Crumples: Crustal Deformation and Mountain Building

Deep Time: How Old Is Old

A Biography of the Earth

Riches in Rock: Energy and Mineral Resources

Unsafe Ground: Landslides and Other Mass Movements

Streams and Floods: the Geology of Running Water

Restless Realm: Oceans and Coasts

A Hidden Reserve: Groundwater

Dry Regions: the Geology of Deserts

Amazing Ice: Glaciers and Ice Ages

Global Change in the Earth System

Introducing Rocks

A Surface Veneer: Sediments and Soils

The Rock Cycle

The Earth’s Interior Revisited: Insights from Geophysics

Memories of Past Life: Fossils and Evolution

Ever-Changing Landscapes and the Hydrologic Cycle

Prelude: And Just What is Geology?

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