Deck 2: Plate Tectonics and Physical Hazards

Question 1

Which of the following is true?

A) Earth's crust is denser than the mantle.
B) Earth's crust is thicker than the mantle.
C) Earth's crust is part of the asthenosphere and equivalent to it in composition.
D) Earth's crust is part of the mantle and forms the upper part of it.
E) Earth's crust is less dense than the mantle.

Answer 1

E

Question 2

The San Andreas Fault is:

A) a normal fault.
B) the subduction zone bordering the Pacific Plate.
C) a rift zone running the length of California.
D) a reverse fault.
E) a transform fault.

Answer 2

E

Question 3

Near which type of lithospheric plate boundary are andesite stratovolcanoes most common?

A) rift zones on continents
B) collision zones between continental plates
C) subduction zones between oceanic and continental plates
D) subduction zones between two continents
E) transform fault boundaries between oceanic and continental plates

Answer 3

C

Question 4

Along which type of lithospheric plate boundaries are earthquakes common?

A) only convergent (subduction zones)
B) only divergent (spreading zones)
C) only transform
D) only divergent and transform
E) convergent, divergent, and transform

Question 5

How does rhyolite magma form in the line of arc volcanoes like the Cascades?

A) Rhyolite is not found in the Cascades volcanoes.
B) Basalt magma rising from above the subducted slab rises to melt continental crust to form the rhyolite.
C) The subducted slab gets hot enough at depth that it melts to form rhyolite.
D) Friction at the top of the subducted slab heats the mantle to form rhyolite.
E) Water rising from the subducted slab causes melting of the Earth's mantle to form rhyolite.

Question 6

Along which type(s)of lithospheric plate boundary are basalt-flow eruptions abundant?

A) oceanic rift zones
B) continental rift zones
C) continental collision zones
D) transform faults
E) mantle plumes

Question 7

If the Atlantic Ocean floor is getting wider,why is the Earth not becoming larger?

A) Actually, the Atlantic Ocean floor is not getting wider.
B) Old ocean floor sinks at subduction zones (trenches).
C) It is becoming denser, so it takes up no more space.
D) It becomes part of the edge of the adjacent continent.
E) It melts at oceanic transform faults.

Question 8

Why do many oceanic volcanoes occur as long lines of volcanoes that are active at only one end?

A) The lithosphere moves over a stable hotspot in the mantle.
B) The mantle convection cell under the crust carries the magma source from one end of the line of volcanoes to the other.
C) The mantle plume that feeds the volcano rotates around the Earth's core, tracing new volcanoes as it does.
D) The spreading lithosphere pushes the underlying magma source across the ocean floor.
E) The active volcanoes are gradually moving away from the oceanic ridge.

Question 9

Before people understood plate tectonics,what evidence led some scientists to believe in continental drift?

A) Rocks on the ocean floor are oldest in the center, becoming progressively younger toward each continent.
B) Rocks on the continents can be traced through the ocean floor to the other side.
C) Anthropologists have found human carvings in Africa that match those in Brazil.
D) Glaciers near the mouth of the Amazon River in Brazil carried distinctive rocks into South Africa, demonstrating that those countries were once connected.
E) Ages of bedrock formations match across the Atlantic Ocean.

Question 10

What is a transform fault characterized by?

A) lithospheric plates sliding past each other
B) the movement of one plate over another
C) the movement of plates away from each other
D) the movement of one plate down against another
E) earthquakes but no plate movement

Question 11

What direction is the Pacific Plate currently moving,based on the chain of Hawaiian Islands with only the easternmost island active?

A) to the northeast
B) to the northwest
C) to the southeast
D) to the southwest
E) It is not moving; the chain of islands is not related to the active one.

Question 12

Which of the following is NOT true?

A) Subduction zones are areas where ocean floor descends into the mantle.
B) Subduction zone activity includes very large earthquakes.
C) Subduction zone activity leads to active volcanoes.
D) Subduction zones are areas where ocean floor rocks are formed.
E) Subduction zones are marked as the deepest parts of the oceans.

Question 13

Why do the Hawaiian Islands form a chain of volcanoes?

A) The mantle below flows slowly to the east, creating new volcanoes as it goes.
B) The Hawaiian Islands are not part of a chain. They are over a stationary hotspot in the lithosphere.
C) The crack in the lithosphere is progressively splitting eastward, permitting magma to rise along a line.
D) The top of the basalt plume in the deep mantle is dragged eastward by moving lithosphere.
E) The lithosphere carrying Hawaii slowly moves over a hotspot feeding basalt magma to the overlying volcano.

Question 14

Which of the following is true?

A) The mantle is denser than the lithosphere.
B) The lithosphere is denser than the mantle.
C) The asthenosphere is the more rigid equivalent of the mantle.
D) The asthenosphere is the more plastic part of the mantle.
E) The mantle is everywhere more rigid than the crust.

Question 15

Which of the following is true?

A) Transform faults show dominantly vertical movement.
B) Transform faults are only in the ocean basins.
C) Transform faults are areas of spreading and new crustal generation.
D) Transform faults change with time from horizontal to vertical motion.
E) Transform fault motion typically ends abruptly at both ends.

Question 16

What does oceanic lithosphere consist of?

A) basalt on top of peridotite
B) only basalt
C) only peridotite
D) basalt and peridotite in layers of variable thickness, in some places above, in others below
E) partly basalt and partly granite

Question 17

The magnetic stripes of the seafloor are considered evidence of seafloor spreading and:

A) subduction in the rift valleys.
B) spreading centers in the trenches.
C) changes in the Earth's axis of rotation.
D) periodic reversals in the polarity of Earth's magnetic field.
E) periodic collapses of Earth's gravitational field.

Question 18

Why does oceanic lithosphere almost always sink beneath continental lithosphere at convergent plate boundaries?

A) Oceanic lithosphere moves so slowly that it can only sink.
B) Oceanic lithosphere is at the bottom of the ocean, so it can't float high enough to ride over a continent.
C) Oceanic lithosphere is almost twice as dense as the underlying mantle.
D) Oceanic lithosphere is denser than continental lithosphere.
E) Oceanic lithosphere is partly liquid, so it floats on the solid continental lithosphere.

Question 19

Which of the following is true?

A) Oceanic rift zones are found only in the center of the oceans.
B) Rift zones are found only in the ocean basins.
C) Rift zones are areas where oceanic crust is formed.
D) Rift zones are the oldest parts of the oceanic crust.
E) Rift zones mark the boundaries between oceanic and continental crust.

Question 20

Which of the following was NOT used as early evidence for continental drift?

A) ages of bedrock formations that match across the Atlantic Ocean
B) match of coastlines across the Atlantic Ocean
C) match of rock formations across the Atlantic Ocean
D) match of ages of continental rocks across the Atlantic Ocean
E) the fact that the magnetic pole shifts from north to south

Question 21

In what tectonic environment that is not at a plate boundary are major volcanoes found? Identify one of these in an ocean basin and one on a continent.

Question 22

Along which type(s)of lithospheric plate boundary are basalt-flow eruptions abundant? Provide a real example (name or location).

Question 23

Discuss the evidence that proves that continental drift exists.

Question 24

Why do many oceanic volcanoes occur as long lines of volcanoes that are active at only one end? How does the process work?

Question 25

List the three main tectonic environments for large earthquakes in western North America and name a specific example of each.

Question 26

Why do volcanoes occur near some plate boundaries but not near others?

Question 27

In the line of arc volcanoes,like the Cascades of Washington and Oregon,over an active subduction zone,a series of events leads to the magmas that erupt at the surface.What magma forms first,and where and how does it form?

Question 28

Discuss the three types of plate boundaries included in this chapter and provide examples of each.

Question 29

Distinguish between Earth's crust and mantle.

Question 30

What keeps the Appalachians standing as a mountain range even though they have been continuously eroding since they formed hundreds of millions of years ago?

Question 31

Explain why people living near the San Andreas Fault are at a huge risk of experiencing a natural disaster.

Question 32

Do tectonic plates consist of crust,mantle,or some combination of crust and mantle,and if so,what part or parts of each?

Question 33

Distinguish between Earth's lithosphere and asthenosphere in terms of both location and properties.

Question 34

What was the primary reason why Alfred Wegener's theory of continental drift was rejected?

Question 35

How did scientists use the scientific method to support Wegener's hypothesis of continental drift?