Deck 21: Plate Tectonics and Earths Interior

Question 1

An Earthquake occurs as

A)seismic waves travel to Earth's surface.
B)energy released from Earth's interior travels to Earth's surface.
C)energy released at Earth's surface travels to Earth's interior.
D)seismic waves travel to Earth's interior.
E)energy released from Earth's interior travels in the form of seismic waves to Earth's surface.

Answer 1

E

Question 2

Seismic waves are classified as body waves and surface waves. An example of a body wave is a

A)Primary wave (P-wave).
B)Love wave.
C)Rayleigh wave.
D)Tertiary wave (T-wave).

Answer 2

A

Question 3

In comparison to S-waves, P-waves

A)vibrate the particles of their medium up and down and side-to-side.
B)can travel through solid granite, magma, water and/or air.
C)can travel only through solids, not through fluids.
D)are the second seismic wave to register on a seismograph.

Answer 3

B

Question 4

Earth's internal layers were discovered by studying the propagation of P- and S- waves through Earth's interior. In comparison to S-waves, the movement of P-waves is

A)fast, compressing and expanding the rock as they move through it.
B)fast, vibrating the rock particles up and down and side-to-side.
C)slower and can travel through solid granite, magma, water or air;
D)slower and can travel only through solids, not liquids.

Question 5

What are the two major kinds of waves an earthquake produces?

Question 6

The propagation of seismic waves through Earth's interior provides evidence of internal layering. The first boundary discovered was between the

A)upper and lower mantle.
B)inner and outer core.
C)outer core and the mantle.
D)mantle and the crust.

Question 7

A seismograph

A)predicts earthquakes.
B)measures ground movement.
C)helps prevent earthquakes.
D)measures fault displacement.

Question 8

Earth's internal layers were discovered by studying the propagation of P- and S- waves through Earth's interior. In comparison to P-waves, the movement of S-waves are

A)faster and compresses and expands the rock as they move through it.
B)faster and vibrates rock particles up and down and side-to-side.
C)slower and can travel through solid granite, magma, water or air;
D)slower and they can only travel through solids, not liquids.

Question 9

Body waves can be divided into two types-primary waves and secondary waves. What is the difference between these two types of body waves?

Question 10

Motion in a P-wave is

A)side to side.
B)transverse.
C)longitudinal.
D)up and down.

Question 11

In comparison to P-waves, S-waves

A)compress and expand the rock as they move through it.
B)can travel through all mediums-solid granite, magma, water and/or air.
C)can travel only through solids-not in fluids.
D)are fast and the first to register on a seismograph.

Question 12

Earth's internal layers were discovered by studying

A)seismic waves.
B)the Mohorovicic discontinuity.
C)Rayleigh and Love waves.
D)convection cells.

Question 13

The fastest seismic wave is a

A)Primary wave.
B)Secondary wave.
C)Tertiary wave.
D)Rayleigh wave.

Question 14

Compare the relative speeds of primary and secondary seismic waves, and relate speeds of travel to the medium in which the waves travel.

Question 15

Secondary waves can travel through all areas of Earth except the

A)surface.
B)outer core.
C)inner core.
D)mantle.

Question 16

Which seismic waves produce a wave shadow?

A)P-waves.
B)Love waves.
C)S-waves.
D)P- and S- waves

Question 17

The speed of a seismic wave depends on

A)the type of material it travels through.
B)how far it has to travel.
C)its amplitude.
D)its frequency.

Question 18

In comparison to S-waves, P-waves

A)cannot travel through solids, they only travel through fluids.
B)are the fastest of all seismic waves and the first to register on a seismograph.
C)are the second to register on a seismograph.
D)all of the above.

Question 19

How can the location and the strength of an earthquake be determined?

Question 20

Earthquake P-waves

A)travel in straight lines through Earth's core.
B)cannot propagate through Earth's core.
C)are transverse vibrations similar to sound waves.
D)are longitudinal vibrations similar to sound waves.

Question 21

The asthenosphere is part of the

A)crust.
B)lithosphere.
C)mantle.
D)outer core.

Question 22

Evidence to support the fact that Earth's central core is solid can be attributed to

A)a decrease in S-wave velocity as they encounter and move through the inner core.
B)an increase in P-wave velocity as they encounter and move through the inner core.
C)a decrease in P-wave velocity as they encounter and move through the inner core.
D)an increase in S-wave velocity as they encounter and move through the inner core.

Question 23

The mantle can be separated into two different portions: the lower mantle and the upper mantle. The lower mantle is

A)completely solid due to extreme pressure that prevents iron-rich silica rocks from melting.
B)composed of silly putty that flows like molasses.
C)rigid and has no capability of flow.
D)predominantly liquid silica.

Question 24

The outer core is

A)rock.
B)plastic.
C)liquid.
D)the source for volcanoes.

Question 25

Continental crust extends farther down into the mantle than oceanic crust because

A)it is thicker than oceanic crust.
B)oceanic crust is buoyant and rides atop the mantle.
C)it is heavier than oceanic crust.
D)it sinks into the mantle and asthenosphere.

Question 26

The Mohorovicic discontinuity was discovered by observing

A)earthquake movement at Earth's surface.
B)seismograms of an earthquake.
C)changes in rock density.
D)all of these

Question 27

We can say that Earth's crust floats on the mantle because

A)the mantle is very hot and flows from internal convection.
B)part of the mantle is hot enough to flow as a plastic solid.
C)the continental crust floats on the oceanic crust.
D)the mantle is below the crust.

Question 28

The lithosphere includes

A)continental and oceanic crust.
B)the crust and the upper part of the mantle.
C)part of the mantle and the crust.
D)continental and oceanic crust and the upper part of the mantle.

Question 29

P-waves travel faster through the inner core than the outer core because the inner core is

A)hotter than the outer core.
B)the same as the outer core.
C)rock.
D)solid.

Question 30

The upper mantle can be divided into two portions, the

A)asthenosphere (lower zone of the upper mantle)and part of the lithosphere (the top zone of the upper mantle).
B)asthenosphere (top zone of the upper mantle)and the lithosphere (the lower upper mantle).
C)Moho and the lithosphere.
D)continental mantle and the oceanic mantle.

Question 31

The Mohorovicic discontinuity marks the change in rock density elasticity between the

A)inner and outer core.
B)core and the mantle.
C)mantle and the crustal surface.
D)asthenosphere and lithosphere.

Question 32

The Earth's layer with plastic-like behavior is the

A)mantle.
B)crust.
C)inner core.
D)outer core.

Question 33

Because S-waves do not travel through Earth's outer core, scientists inferred that the outer core is

A)impenetrable.
B)molten liquid.
C)solid.
D)very dense.

Question 34

The outer core

A)has a plasticlike flow.
B)flows fast enough to power Earth's magnetic field.
C)is solid as a rock.
D)transmits S-waves.

Question 35

Earth's magnetic field is not stable; throughout geologic time it has changed direction. This change is attributed to

A)changes in the direction of fluid flow in the molten outer core of Earth.
B)magnetic pole reversals.
C)fluctuations in the time / space continuum.
D)changes in the direction of fluid flow in the molten inner core of Earth.

Question 36

Continental crust is

A)thinner than oceanic crust.
B)less dense than oceanic crust.
C)more dense than oceanic crust.
D)thinner and more dense than oceanic crust.

Question 37

The Earth's magnetic field is attributed to the

A)flow of molten liquid in Earth's inner core.
B)flow of molten fluid in Earth's outer core.
C)movement of lithospheric plates in the outer mantle.
D)movement of lithospheric plates at Earth's surface.

Question 38

The thickness of Earth's crust

A)varies from 10 km under the continents to 60 km under the oceans.
B)on average is about 10 km.
C)on average is about 60 km.
D)varies from 10 km under the oceans to 60 km under the continents.

Question 39

The Mohorovicic discontinuity occurs because of a

A)change in temperature with depth.
B)shift in the density of minerals with the same composition.
C)change in the composition of rocks on both sides of the boundary.
D)density change in rocks of the same composition on both sides of the boundary.

Question 40

The lithosphere rides on top of the asthenosphere. Lithospheric movement causes

A)earthquakes, volcanic activity, and mountain building activity.
B)the subduction of continental crust under oceanic crust.
C)hot-spot activity as found in Hawaii.
D)widespread destruction.

Question 41

Evidence to support that the inner core is solid and the outer core is liquid comes from

A)refraction of seismic waves as they encounter different mediums.
B)the wave shadow effect of P- and S-waves as they encounter the solid and liquid core.
C)the wave shadow effect of P- and S-waves, and the increase in velocity of P-waves as they encounter the solid inner core.
D)the inner core is not solid, but is liquid.

Question 42

The Earth's magnetic field is generated in

A)outer space.
B)the crust.
C)the mantle.
D)the outer core.

Question 43

Earth's core is probably composed of

A)silicate minerals.
B)aluminum oxides.
C)an iron-nickel alloy.
D)calcium magnesium sulfate.

Question 44

The outer core is liquid because

A)it is magnetically charged, and, like a magnet, energy flows from one region to another.
B)the inner core is solid.
C)there is less weight, and thus less pressure on it.
D)it is composed of molten iron.

Question 45

The inner core is solid because

A)it is composed of iron and nickel.
B)the surrounding outer layers act as a blanket to insulate the core.
C)pressure from the weight of the surrounding layers prevents the inner core from melting.
D)none of these, for the inner core is not solid, but is liquid

Question 46

Movement of the lithosphere

A)has a plasticlike flow.
B)causes earthquakes and volcanic activity.
C)has a leisurely pace and allows the formation of gentle rolling hills.
D)is intermittent.

Question 47

The upper mantle is the region known as the

A)asthenosphere.
B)lithosphere.
C)mohorovicic.
D)centrosphere.

Question 48

The mantle is composed of

A)iron and nickel.
B)iron-rich silicate rocks.
C)half liquid and half rocky material.
D)solid rock.

Question 49

The lithosphere floats atop the

A)mantle.
B)crust.
C)asthenosphere.
D)mohorovicic.

Question 50

Does the fact that the mantle is beneath the crust necessarily mean that the mantle is denser than the crust? Explain.

Question 51

The outer core is thought to be molten because it

A)is denser than the inner core.
B)will not transmit P-waves.
C)is made of iron and nickel.
D)will not transmit S-waves.

Question 52

The Earth's lithosphere

A)is the same as the crust.
B)consists of the crust and the asthenosphere.
C)is the same as the mantle.
D)consists of the crust and the uppermost part of the mantle.

Question 53

The crustal surface varies in

A)composition, density, and thickness.
B)isostasy, density, and rock competence.
C)thickness-the oceanic crust is thinner than the continental crust.
D)density-the oceanic crust is heavier than the continental crust.

Question 54

The primary evidence that the outer core is molten is an abrupt

A)increase in the velocity of P-waves, but no increase in S-waves.
B)increase in the velocity of L-waves.
C)stop of S-wave propagation, and a decrease in P-wave velocity.
D)stop of P-wave propagation, and a decrease in S-wave velocity.

Question 55

Thermal convection movement in the upper mantle

A)generates the electric current that powers Earth's magnetic field.
B)greatly influences Earth's surface features.
C)heats Earth's core by frictional forces.
D)is usually negligible.

Question 56

Isostasy is

A)crustal equilibrium relative to the mantle.
B)the buoyant force exerted on the mantle by oceanic crust.
C)the buoyant force exerted on the mantle by continental crust.
D)crustal equilibrium relative to Earth's surface.

Question 57

The top of the mantle is the same as the

A)base of the core.
B)base of the lithosphere.
C)top of the asthenosphere.
D)base of the crust.

Question 58

Compared with oceanic crust, continental crust is very buoyant because it is

A)composed of basaltic rock that contains air bubbles from successive lava flows.
B)composed of granitic rocks whereas oceanic crust is composed of basaltic rocks.
C)thinner and forms a thin upper skin on the oceanic crust below.
D)very young and fresh.

Question 59

What is the evidence for Earth's central core being solid?

Question 60

The crustal surface and the uppermost part of the mantle is called the

A)asthenosphere.
B)lithosphere.
C)mohorovicic.
D)centrosphere.

Question 61

When the magnetic field of Earth is reversed,

A)Earth flips over in its orbit.
B)Earth's rotation is also reversed.
C)newly formed mineral grains on the ocean floor are magnetized according to the new orientation of the magnetic field.

Question 62

The ocean crust

A)becomes progressively younger away from the mid-ocean ridges.
B)is the same age worldwide.
C)becomes progressively older away from the mid-ocean ridge.
D)ranges in age, the oldest ocean crust is in the Atlantic and the youngest is in the Arctic.

Question 63

In the 1950s a plot of the position of the magnetic north pole through time revealed that

A)either the magnetic poles had migrated through time or the continents had moved.
B)polar magnetization varied from pole to pole.
C)over the past 500 million years the geographic poles changed position at least once or twice.
D)all of the above.

Question 64

The theory of continental drift is attributed to

A)H.H. Hess.
B)Alfred Wegener.
C)W. Loma Prieta.
D)Simon Tectonic.

Question 65

How did plant and animal fossils influence the theory of continental drift?

Question 66

According to the theory of seafloor spreading, molten rock is rising up along

A)the mid-ocean ridges.
B)trenches that border continental margins.
C)islands surrounding the Pacific volcanic rim.
D)areas of sinking seafloor.

Question 67

Describe the theory of continental drift.

Question 68

In a reconstruction of Earth's geologic past, the continents of Africa and South America fit best along the

A)shorelines.
B)continental shelves.
C)continental slopes.
D)ocean floors.

Question 69

Wegener's theory of continental drift

A)was first considered a monumental breakthrough in science.
B)was not accepted by the scientific community of the early 1900's.
C)proved that heat flows convectively below Earth's surface .
D)has been proved wrong.

Question 70

The Earth's magnetic field

A)never appreciably changes.
B)has reversed itself many times.
C)is centered at Earth's core.
D)both B and C

Question 71

Which of the following did Alfred Wegener NOT use to support his theory of continental drift?

A)Paleoclimate data.
B)Similar fossils on widely separated continents.
C)Paleomagnetic data.
D)Similar rocks on widely separated continents.

Question 72

What evidence did Wegener use to support his hypothesis of continental drift?

A)sea-floor spreading
B)paleoclimatic data
C)polar reversals
D)transform fault boundaries

Question 73

Paleomagnetism from a rock gives information on the

A)direction from the rock to the North Pole.
B)present-day magnetic field.
C)amount of iron in the rock.
D)magnetic field at the time the rock was formed.

Question 74

How does erosion and wearing away of a mountain affect the depth to which the crust extends into the asthenosphere?

Question 75

The theory of continental drift is supported by paleoclimate data, paleontology, and

A)paleomagnetic data.
B)seafloor spreading.
C)transform boundaries.
D)the jig-saw fit of the continents at their continental margins.

Question 76

The theory of continental drift is supported by paleoclimatic data, the jig-saw fit of the continents

A)paleontology, and paleomagnetic data.
B)and seafloor spreading.
C)transform boundaries, and paleontology.
D)at their continental margins, and paleontology.

Question 77

Detailed mapping of the ocean floors revealed

A)huge mountain ranges beneath the oceans.
B)deep trenches near some of the continents.
C)that the oceans are equally deep at all locations.
D)huge mountain ranges on the ocean floor, and deep trenches near some of the continents.

Question 78

What is the principle of isostasy, and what evidence supports it?

Question 79

Alfred Wegener supported his theory of continental drift by

A)fitting together the shorelines of the African and South American continents.
B)using paleoclimatic data-evidence of glaciers in the Northern Hemisphere.
C)paleomagnetic data.
D)making a connection between rocks, rock structures, and plant and animal fossils found in both Africa and South America.

Question 80

The theory of seafloor spreading is supported by

A)geological, biological, and climatological data.
B)paleomagnetic analysis of the ocean's floor.
C)the change in Earth's polarity.
D)none of these