Chapter 10: Volcanoes Flashcards
(20 cards)
Magma forms when solid rock in the crust and upper mantle
a. partially melts.
b. crystallizes.
c. vaporizes.
d. cools.
a. partially melts.
Which type of landform develops at plate boundaries where one oceanic plate descends beneath another?
a. rift valley
b. volcanic island arc
c. mountain formed by a batholith
d. lava plateau
a. rift valley
At divergent plate boundaries in the ocean, magma rises and melts because of
a. higher temperatures at the surface.
b. a decrease in pressure.
c. intrusive plutons at the boundary.
d. increased silica content of magma.
b. a decrease in pressure.
What are the landforms at divergent ocean plate boundaries?
a. mid-ocean ridges
b. island arcs
c. continental arcs
d. ocean trenches
d. ocean trenches
Most intraplate volcanic activity occurs where
a. oceanic plates diverge.
b. mantle plumes rise toward the surface within a plate.
c. hot magma descends into the mantle under a plate.
d. oceanic and continental plates converge.
a. oceanic plates diverge.
As the temperature of lava increases,
a. its viscosity decreases.
b. it begins to harden.
c. its viscosity increases.
d. it can flow a much shorter distance.
a. its viscosity decreases.
What type of volcano is fairly symmetrical and has both
layers of lava and pyroclastic deposits?
a. a cinder cone volcano
b. a shield volcano
c. a pyroclastic volcano
d. a composite cone volcano
d. a composite cone volcano
What is a caldera?
a. a fiery volcanic explosion
b. a type of volcano
c. a large depression in a volcano
d. a very large volcanic bomb
c. a large depression in a volcano
Lava plateaus form when
a. the top of a volcano collapses.
b. fluid basaltic lava flows out of fissures.
c. lahars create new landforms.
d. pyroclastic flows erupt from volcanoes.
b. fluid basaltic lava flows out of fissures.
Structures that form from the cooling and hardening of magma beneath Earth’s surface are
a. vents.
b. calderas.
c. lahars.
d. plutons.
d. plutons.
Which of the following is NOT a factor in how violently or
quietly a volcano erupts?
a. magma’s composition
b. magma’s temperature
c. magma’s concentration of dissolved gases
d. magma’s depth inside a volcano’s vent
b. magma’s temperature
What is a volcanic bomb
a. a very violent volcanic explosion
b. a particle larger than 64 mm in size ejected as glowing lava
c. a pocket of gas that is released suddenly
d. a tiny particle of ejected rock less than 64 mm in size
b. a particle larger than 64 mm in size ejected as glowing lava
The particles produced in volcanic eruptions are called
a. pyroclastic materials.
b. laccoliths.
c. calderas.
d. volcanic stocks.
a. pyroclastic materials.
Which of the following plays a major part in determining the form of a volcano?
a. elevation above sea level
b. magma composition
c. local soil type
d. nearness of other volcanoes
b. magma composition
When a common type of basaltic lava hardens, it forms aa, which has
a. a surface made of cinders.
b. a smooth surface that is wrinkled.
c. a rough, jagged surface.
d. holes that ooze hot water.
c. a rough, jagged surface.
Most shield volcanoes have grown from the ocean floor to form
a. islands.
b. dikes.
c. canyons.
d. tectonic plates.
a. islands.
The broad, slightly dome-shaped volcanoes of Hawaii are
a. composite cone volcanoes.
b. pyroclastic volcanoes.
c. shield volcanoes.
d. cinder cone volcanoes.
a. composite cone volcanoes.
Which type of intrusive feature forms when magma is injected into fractures cutting across rock layers?
a. a laccolith
b. a dike
c. a lava plateau
d. a sill
d. a sill
Which of the following is NOT true of a batholith?
a. It may be uplifted and then exposed by erosion.
b. It is the largest intrusive igneous body.
c. It may form the core of a mountain range.
d. It is often a small part of a sill.
b. It is the largest intrusive igneous body.
Which of the following is similar to a batholith but has less than 100 square kilometers exposed?
a. stock
b. sill
c. laccolith
d. dike
b. sill
