Deck 12: Earths Interior

Question 1

Which physical property is responsible for determining how Earth materials separate into interior layers?

A)Density
B)Color
C)Molecular charge
D)Tensile strength

Answer 1

A

Question 2

Where is the thinnest continental crust in North America?

A)Appalachian Mountains
B)Mississippi River Valley
C)Basin and Range region
D)Colorado Plateau

Answer 2

C

Question 3

An earthquake occurs in California.What is the minimum magnitude an earthquake can have if it is to be picked up by seismographic networks around the world?

A)M 5.5
B)M 7
C)M 8
D)M 9.5

Answer 3

A

Question 4

What is diffraction?

A)A seismic wave is bounced back toward its source.
B)A seismic wave is bent when moving from one material to another.
C)A seismic wave is bent when it passes by a curved surface.
D)Seismic waves are separated by liquids

Question 5

As of 2015, what was the deepest drill core yet taken that allowed scientists to study the Earth's interior?

A)7)6 km
B)12.3 km
C)15 km
D)50.5 km

Question 6

Where is oceanic crust generated?

A)Along divergent plate boundaries
B)Where volcanic lava meets the sea
C)Where continents collide
D)Where magma bodies are emplaced deep in the crust

Question 7

Which of the following materials will allow for the fastest transmission of seismic waves?

A)Rigid, less compressible material
B)Material that has been slightly heated
C)Partially molten material
D)Molten material

Question 8

What is the primary method scientists use to determine the layering of the interior of the Earth?

A)Drill cores
B)Volcanic rocks
C)Sonar
D)Seismic waves

Question 9

Where is the thickest continental crust in North America?

A)Appalachian Mountains
B)Rocky Mountains
C)Basin and Range region
D)Great Basin

Question 10

What is the difference in densities between the upper mantle and the lower mantle?

A)2)7 & 3.0 g/cm³
B)3)0 & 3.3 g/cm³
C)3)3 &5.6 g/cm³
D)10 & 12.1 g/cm³

Question 11

What will happen to a seismic wave when it is refracted?

A)The wave will be bent when passing into a material of differing density.
B)The wave will undulate.
C)The wave will be bounced back toward its source.
D)Nothing will change the wave.

Question 12

What will happen to a seismic wave when it is reflected?

A)The wave will be bent.
B)The wave will undulate.
C)The wave will be bounced back toward its source.
D)Nothing will change the wave.

Question 13

Which atom is easier to compress when pressure is squeezing a rock and why?

A)Negative ion; it has more electrons and is "fluffier."
B)Positive ion; it has fewer electrons and is already densely compact.
C)Negative ion; electrons are easier to remove.
D)Positive ion; it is less resistant and easier to compress.

Question 14

________ is the process where materials separate into different layers due to density.

A)Shearing
B)Differentiation
C)Phase change
D)Tensional stress

Question 15

P waves moving through the base of continents move at about ________ km/sec, but once they cross the Moho, the velocity changes to ________ km/sec.

A)8; 4
B)2; 10
C)6; 8
D)3; 9

Question 16

What is the average thickness of the oceanic crust?

A)4 km
B)7 km
C)40 km
D)70 km

Question 17

Which seismic wave(s)would be most useful in determining the extent and thickness of the Earth's interior layers?

A)P waves
B)P and S waves
C)S waves
D)Surface waves

Question 18

Why do seismic waves follow strongly curved paths as they move through the interior?

A)Their paths are altered by changes in temperature.
B)Their paths are altered by reflection off dense materials.
C)Their velocities are altered by changes in chemistry.
D)Their velocities are changed because of increasing pressure with depth.

Question 19

What is a mineral phase change?

A)A mineral melts from a solid state to a liquid state.
B)The exterior of a mineral weathers and changes color.
C)A mineral changes density because of the addition of water.
D)Atoms in a mineral are rearranged into a denser and more stable structure.

Question 20

Which one of the following is not one of the three compositionally distinct layers of the Earth's interior?

A)Crust
B)Mantle
C)Lower mantle
D)Core

Question 21

Which layer of Earth makes up more than 82 percent of the volume of the planet?

A)Outer core
B)Crust
C)Mantle
D)Inner core

Question 22

Which layer is thought to be the birthplace of deep mantle plumes?

A)Transition zone
B)Outer core
C)D" layer
D)Shadow zone

Question 23

________ is a technique to view three-dimensional changes in composition and density by using seismology.

A)Magnetometry
B)Paleomagnetism
C)Chemical convection
D)Seismic tomography

Question 24

Which layer or layers of the interior are believed to have convection cells?

A)Mantle
B)Mantle and outer core
C)Inner core
D)Outer core and inner core

Question 25

How is the shape of Earth affected by its rotation?

A)Earth is perfectly round.
B)The poles are further from the center of Earth than the equator.
C)The equator is further from the center of Earth than the poles.

Question 26

Heat will transfer by ________ in the outer core.

A)radiation
B)convection
C)conduction and convection
D)conduction

Question 27

Where is the highest rate of heat flow escaping the Earth's interior?

A)At mid-ocean ridges
B)At subduction zones
C)At volcanoes
D)At mountain ranges

Question 28

How does water get from the surface to the middle of the mantle?

A)Percolation via pores and fractures
B)Subterranean streams
C)Seawater seeping into the interior at mid-ocean rifts
D)Subducting oceanic lithosphere

Question 29

Which of the following materials would cause the greatest gravity anomaly?

A)Quartz
B)Water
C)Granite
D)Metallic ore

Question 30

Of the three mechanisms of heat transfer, which is the only one that does not operate in the interior of Earth?

A)Convection
B)Radiation
C)Conduction

Question 31

Which of the following material properties will not result in a seismic velocity anomaly when using seismic tomography?

A)Confining pressure
B)Composition
C)Temperature
D)Water content

Question 32

What materials make up Earth's core?

A)Perovskite and silica
B)Iron and nickel
C)Olivine and pyroxene
D)Sulfur and aluminum

Question 33

Why might there be density changes between different parts of the same layer of the planet?

A)Different materials make up different regions of the same layer.
B)Some materials may compress when squeezed by overlying rock.
C)Repelling forces may cause some atoms to expand.
D)Differentiation is still separating materials into distinct interior layers.

Question 34

What is the average geothermal gradient in the crust?

A)20°C/km
B)30°C/km
C)45°C/km
D)100°C/km

Question 35

The ________ is a seismic boundary between the crust and the mantle where there is a dramatic increase in seismic wave velocity.

A)Schrodinger discontinuity
B)Greenschist facies
C)Low-velocity pathway
D)Moho boundary

Question 36

What is the dominant mineral in the lower mantle?

A)Perovskite
B)Olivine
C)Quartz
D)Pyroxene

Question 37

The inner core is believed to rotate independently from the outer layers of Earth.Why is this possible?

A)The immense interior pressures generate rotation.
B)The inner core is separated from the mantle by the liquid outer core and can spin freely.
C)Radioactive decay generates spin.
D)Frictional drag pushes the inner core at a different rate than the rest of the planet.

Question 38

A ________ occurs when an iron-rich fluid in the core is electrically charged and flowing, which generates a magnetic field.

A)geotherm
B)geodynamo
C)geophysical anomaly
D)geosyncline

Question 39

The composition of the upper mantle is defined by ________.

A)granite
B)quartz
C)perovskite
D)peridotite

Question 40

What is the average rate of temperature increase in the mantle?

A)0)3°C/km
B)0)7°C/km
C)1°C/km
D)1)3°C/km

Question 41

Outside of the crust, the layer that scientists know the most about is the mantle.Other than via seismic waves, how else do geologists obtain information about the composition of the mantle?

A)Drill cores
B)Volcanoes
C)Sonar
D)Seismic waves

Question 42

The magnetic north pole is currently moving (toward /away from)the geographic North Pole, and the magnetic south pole is currently moving (toward /away from)the geographic South Pole.

A)toward; toward
B)toward; away from
C)away from; toward
D)away from; away from

Question 43

The mantle is composed of pure nickel and iron.

Question 44

Why is conduction not an efficient way to move heat through most of the Earth?

A)Radioactive decay generates too much heat.
B)Molecules are too far apart to transfer heat via that method.
C)Rocks are poor conductors of heat.
D)Radiation is the most efficient way to move heat through the interior.

Question 45

P waves cannot penetrate the outer core because it is liquid.

Question 46

When olivine is undergoing a mineral phase change due to pressure, what mineral will it form?

A)Perovskite
B)Quartz
C)Pyroxene
D)Spinel

Question 47

Which process is responsible for Earth's magnetic field? In which layer does this process occur?

A)Radiation; upper mantle
B)Subduction; lower mantle
C)Convection; outer core
D)Crystallization; inner core

Question 48

The inner core is shrinking.

Question 49

Oceanic crust is compositionally more similar to the mantle than to continental crust.

Question 50

________ are responsible for the heat generated in the interior today.

A)Meteorite impacts
B)Magma plutons
C)Short-lived radioactive isotopes
D)Nuclear reactions

Question 51

The inner core and the outer core are compositionally the same.The major difference between them is the states of matter in which they exist.

Question 52

Seismic tomography requires only the data from one earthquake in order to "see" all parts of the Earth's interior.

Question 53

The following choices contain densities of various materials.Based on this data, which will yield the fastest seismic velocity?

A)2)7 g/cm³
B)3)0 g/cm³
C)3)3 g/cm³
D)5)6 g/cm³

Question 54

What is the average density of oceanic crust?

A)2)7 g/cm³
B)3)0 g/cm³
C)3)3 g/cm³
D)5)6 g/cm³

Question 55

What physical property of continents makes them difficult to subduct?

A)Age
B)Temperature
C)Low density
D)Thickness

Question 56

In the D" layer, the portion of the mantle closest to the core-mantle Boundary is hypothesized to be partially melted because the S-wave velocities decrease by 30% when passing through it.

Question 57

If the outer core is cooler than the inner core, why is it in a liquid state?

A)It has more radioactivity than in the inner core.
B)It is under less pressure than the inner core.
C)It has greater water content than the inner core.
D)It has higher density materials than the inner core.

Question 58

Since humans cannot access the core, what objects do scientists use as a proxy to determine the composition of the inner and outer core?

A)Volcanic rocks
B)Meteorites
C)Comets
D)Glaciers

Question 59

Which of the following factors contributed toward the early increase in temperature in the Earth's interior?

A)Impact from planetesimals
B)Friction between landmasses
C)Friction between landmasses and radioactive decay
D)Radioactive decay and impact from planetesimals

Question 60

What is the average density of continental crust?

A)2)7 g/cm³
B)3)0 g/cm³
C)3)3 g/cm³
D)5)6 g/cm³

Question 61

Which of the following is a positive gravity anomaly on this map?

A)Location A
B)Location B
C)Location C
D)Location D

Question 62

What seismic shadowing zone is visible in this image?

A)P-wave shadow
B)S-wave shadow
C)Surface wave shadow
D)Seismic ray shadow

Question 63

This seismic tomographic slice of Earth indicates the variations in S-wave speeds through the interior.Through which region will S waves move the fastest?

A)Pacific Ocean
B)Farallon plate
C)Mid-Atlantic Ridge
D)Africa

Question 64

Is the force of gravity the same over the Earth's surface? Explain why or why not.

Question 65

Which of the following is a negative gravity anomaly on this map?

A)Location A
B)Location B
C)Location C
D)Location D

Question 66

Scientists have subdivided the upper mantle into three sections based on environmental and compositional differences.What are these three subdivisions and how do they compare to each other?

Question 67

The inner core has not always existed, but formed over time.Explain how conditions in the Earth changed over time to create an inner core.

Question 68

According to the geothermal gradient, there is an increase in temperature with increasing depth.If that is the case, why isn't the entire interior of the planet molten?

Question 69

Which of these four images would accurately demonstrate the path seismic rays would take through the interior if the interior of Earth was made of uniform materials?

A)

B)

C)

D)

Question 70

What is the definition of a dipolar field?

Question 71

What are the three main mechanisms of convective flow in the outer core?

Question 72

What is chemical convection, and how does it affect the outer core?

Question 73

Explain why S waves are unable to pass through the outer core.

Question 74

Explain how a P-wave shadow will form.Between which degrees will it form?