Geology Exam 2 Chapter 6
Which of the following is a location in which flood basalts erupted? a. Hawaii b. Texas Gulf Coast c. Columbia Plateau
Columbia Plateau
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
a scoria cone that erupts hot molten fragments on an unpopulated Pacific island
Which of the following sites near a volcano might be relatively less dangerous? a. a site that is within the shelter provided by the volcano's central crater b. a site on a ridge as opposed to a site in a valley c. a site protected by steep slopes of the volcano d. a site where rocks have been weakened by hot volcanic fluids
a site on a ridge as opposed to a site in a valley
Which of the following factors indicates a high risk for volcanic mudflows or lahars? a. a volcano with a thick covering of snow or ice b. a shield volcano that forms a low mountain in the tropics c. a volcano whose hillslopes are covered with hard basaltic lava d. all of these are correct
a volcano with a thick covering of snow or ice
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 are correct
all of these are correct
Which of the following activities is NOT used to monitor volcanoes? a. measuring seismic activity with seismic instruments b. measuring sulfur dioxide gas emissions c. measuring changes in heat flow from satellites d. measuring tilting on the flanks of a volcano e. all of these are correct
all of these are correct
Which of the following are characteristics typical of volcanic domes? a. steep-sided b. rubble-covered surface c. often occur in clusters d. all of these are correct
all of these are correct
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 are correct
all of these are correct
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 are correct
all of these are correct
Which of the following is common in most calderas? a. a large, circuclar depression with steep walls b. thick sequences of volcanic ash c. rounded mountains that are volcanic domes d. all of these are correct
all of these are correct
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 are correct
all of these are correct
The most common volcanic rock found in lava flows on composite volcanoes is a. basalt b. andesite c. obsidian
andesite
Volcanic domes commonly form from all of the following rocks EXCEPT? a. rhyolite b. obsidian c. basalt d. andesite
basalt
Shield volcanoes are composed primarily of a. basalt lava flows b. andesite lava flows c. rhyolite lava flows
basalt lava flows
The largest volcanic eruptions on Earth are floods of... a. andesite magma b. rhyolite magma c. basalt magma
basalt magma
Eruptions of scoria cones are commonly associated with a. lava fountains b. basaltic lava flows c. pyroclastic flow d. basaltic lava flows and lava fountains
basaltic lava flows and lava fountains
If bubbles cannot escape easily from a magma, the resulting eruption is likely to a. produce long, thin lava flows b. be nonexplosive c. be explosive
be explosive
If bubbles cannot escape easily from a magma, the resulting eruption is likely to... a. produce long, thin lava flows b. be explosive c. be nonexplosive
be explosive
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
collapse of the roof of a magma chamber as magma erupts
Match the magma type with the corresponding eruption type. Felsic magma a. fluid lava flows from shield volcanoes; low viscosity b. explosive eruptions from composition volcanoes; high viscosity
explosive eruptions from composition volcanoes; high viscosity
A typical volcanic eruption is likely to kill millions of people at a time. a. true b. false
false
What types of rocks would be most common in a composite volcano? a. scoria and other vesicular basalt b. felsic and intermediate lava flows and tephra c. basalt mostly formed in lava flows d. pillow basalts
felsic and intermediate lava flows and tephra
Match the magma type with the corresponding eruption type. Basaltic magma a. fluid lava flows from shield volcanoes; low viscosity b. explosive eruptions from composition volcanoes; high viscosity
fluid lava flows from shield volcanoes; low viscosity
Volcanic mudflows (lahars) are common on composite volcanoes because... a. hot mud commonly erupts from their central craters b. such volcanoes form preferentially in rainy tropical locations c. large amounts of rain and snowmelt mix with loose ash on steep slopes
large amounts of rain and snowmelt mix with loose ash on steep slopes
What tectonic setting is interpreted to be the cause of volcanism at Yellowstone? a. magma that is coming up along a bend in a transform fault b. subduction along the coast of the Pacific Northwest c. movement of North America over a mantle plume d. a large meteorite impact that struck the area 100 years ago
movement of North America over a mantle plume
Volcanic vents can take which of the following forms? a. narrow linear fissures b. flat-topped mesas c. roughly circular craters
narrow linear fissures, roughly circular craters
Which of the following materials is NOT produced by erupting volcanoes? a. obsidian/glass b. basaltic lava c. sandstone d. ash
sandstone
Magma rising through the crust fractures rocks, producing rhythmic, repeating a. volcanic mudflows b. seismic shaking c. eruptions d. landslide activity
seismic shaking
Which of the following volcanoes is generally the largest? a. scoria cone b. dome c. shield volcano d. composite volcano
shield volcano
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 are correct
they are large mountains with steep slopes
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 are correct
viscous magma prevents gas from escaping easily
Steep-sided hills of viscous lava that pile up over volcanic vents are known as... a. scoria cones b. volcanic domes c. composite volcanoes
volcanic domes
Changes in topography, water chemistry, and gas output all are used to help predict... a. landslides b. harmonic tremors c. volcanic eruptions d. mudflows
volcanic eruptions
