Question 1

What causes the velocity of a P-wave to speed up when it enters the inner core?

Accepted Answer

A) The inner core is a much more dense material than the outer core. 
B) The inner core is a much less dense material than the outer core. 
C) The inner core is liquid,and thus the wave speeds up. 
D) The P-wave no longer has to compete with the S-wave for energy. 
A) The inner core is a much more dense material than the outer core. 
B) The inner core is a much less dense material than the outer core. 
C) The inner core is liquid,and thus the wave speeds up. 
D) The P-wave no longer has to compete with the S-wave for energy. C

Question 2

The graph below shows the change in velocity of seismic waves with depth in the crust.Why does the velocity of the P-wave drop drastically at the core-mantle boundary?

Accepted Answer

A) because the core is much denser than the mantle 
B) because the outer core is solid and P-waves can't pass through solids 
C) because the outer core is liquid and seismic waves travel slower in liquids 
D) because the S-waves are removed and that energy is transferred to the P-waves 
A) because the core is much denser than the mantle 
B) because the outer core is solid and P-waves can't pass through solids 
C) because the outer core is liquid and seismic waves travel slower in liquids 
D) because the S-waves are removed and that energy is transferred to the P-waves C

Question 3

You are studying the seismic data from Mars when you notice that there are no S-waves recorded from 130° through 180° on the opposite side of the planet.What does this information tell you about the interior of Mars?

Accepted Answer

A) There is a layer of solid material in the interior of Mars. 
B) There is a layer of liquid material in the interior of Mars. 
C) There is a layer with a higher-velocity material than the crust below. 
D) There is a layer with a lower-velocity material than the crust below. 
A) There is a layer of solid material in the interior of Mars. 
B) There is a layer of liquid material in the interior of Mars. 
C) There is a layer with a higher-velocity material than the crust below. 
D) There is a layer with a lower-velocity material than the crust below. B

Question 4

If a P-wave is traveling through the Earth and encounters a molten magma chamber,what will happen to the velocity of the P-wave?

Accepted Answer

A) It will slow down. 
B) It will speed up. 
C) It will stay at the same speed. 
D) It will drop to zero. 
A) It will slow down. 
B) It will speed up. 
C) It will stay at the same speed. 
D) It will drop to zero.

Question 5

Using the graph below,why is the outer core liquid,but the inner core solid?

Accepted Answer

A) because the inner core is made of different material than the outer core 
B) because the temperature in the outer core is above melting 
C) because the inner core melts at a much higher temperature 
D) because the pressure on the inner core is much greater 
A) because the inner core is made of different material than the outer core 
B) because the temperature in the outer core is above melting 
C) because the inner core melts at a much higher temperature 
D) because the pressure on the inner core is much greater

Question 6

If an S-wave is traveling through rock when it encounters a magma chamber,the S-wave will ________.

Accepted Answer

A) slow down 
B) speed up 
C) remain at the same speed 
D) not travel through the magma 
A) slow down 
B) speed up 
C) remain at the same speed 
D) not travel through the magma

Question 7

If a P-wave is traveling through sandstone and then encounters peridotite,the P-wave will ________.

Accepted Answer

A) slow down 
B) speed up 
C) remain at the same speed 
D) not travel through the peridotite 
A) slow down 
B) speed up 
C) remain at the same speed 
D) not travel through the peridotite

Question 8

Earth's gravity is best represented by an equipotential surface that contains bumps and depressions where areas of higher or lower gravity appear over the Earth.This representation is called the ________.

Accepted Answer

A) reference geoid 
B) gravitational potential 
C) isostasy 
D) geoid 
A) reference geoid 
B) gravitational potential 
C) isostasy 
D) geoid

Question 9

Which layer of the Earth has the highest density?

Accepted Answer

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

Question 10

The core consists of two layers: the ________ inner core and ________ outer core.

Accepted Answer

A) iron;nickel 
B) nickel;iron 
C) solid;liquid 
D) liquid;solid 
A) iron;nickel 
B) nickel;iron 
C) solid;liquid 
D) liquid;solid

Question 11

Why would the gravity anomaly over a deep-ocean trench be negative?

Accepted Answer

A) because the bathymetry of the trench dips very far below sea level 
B) because the crust being pulled into the trench is less dense than sediments above 
C) because water fills the space above the subducting slab and is much less dense than rock 
D) because the buoyant magma created at the subduction zones is less dense than the rock 
A) because the bathymetry of the trench dips very far below sea level 
B) because the crust being pulled into the trench is less dense than sediments above 
C) because water fills the space above the subducting slab and is much less dense than rock 
D) because the buoyant magma created at the subduction zones is less dense than the rock

Question 12

If a ship weighs 52,000 tons and is in isostatic equilibrium when 6,000 tons of cargo is added,what is the total mass of water that will be displaced by the ship after the cargo is added?

Accepted Answer

A) 6,000 tons 
B) 12,000 tons 
C) 58,000 tons 
D) 52,000 tons 
A) 6,000 tons 
B) 12,000 tons 
C) 58,000 tons 
D) 52,000 tons

Question 13

In the following graph,why does the line for S-waves NOT appear in the outer core?

Accepted Answer

A) S-waves can't travel through the outer core because it is solid. 
B) S-waves can't travel through the outer core because it is liquid. 
C) S-waves disappear after being reflected at the core-mantle boundary. 
D) S-waves can't travel that far into the Earth due to the high amount of iron. 
A) S-waves can't travel through the outer core because it is solid. 
B) S-waves can't travel through the outer core because it is liquid. 
C) S-waves disappear after being reflected at the core-mantle boundary. 
D) S-waves can't travel that far into the Earth due to the high amount of iron.

Question 14

The time it takes for a seismic wave to travel from the focus to a seismometer is called the ________.

Accepted Answer

A) wave front time 
B) P-S wave arrival distance 
C) travel time 
D) seismic ray time 
A) wave front time 
B) P-S wave arrival distance 
C) travel time 
D) seismic ray time

Question 15

Seismic waves travel ________ in solids than in liquids;however,unlike P-waves,S-waves ________ travel through liquids.

Accepted Answer

A) slower;can 
B) slower;can't 
C) faster;can 
D) faster;can't 
A) slower;can 
B) slower;can't 
C) faster;can 
D) faster;can't

Question 16

Why are magnetic anomalies of continental crust so much more complicated than those of oceanic crust?

Accepted Answer

A) The continents are much older and thus have had more time for the minerals to become magnetized. 
B) The continents contain abundant iron minerals,whereas the oceanic crust does not contain any iron minerals. 
C) The continents contain a random orientation of minerals that become magnetized when they interact with the magnetic field. 
D) The continents contain a complex distribution of igneous intrusions,lava flows,and iron-rich sediments. 
A) The continents are much older and thus have had more time for the minerals to become magnetized. 
B) The continents contain abundant iron minerals,whereas the oceanic crust does not contain any iron minerals. 
C) The continents contain a random orientation of minerals that become magnetized when they interact with the magnetic field. 
D) The continents contain a complex distribution of igneous intrusions,lava flows,and iron-rich sediments.

Question 17

If a gravity anomaly is negative,what does that imply about the material underground?

Accepted Answer

A) The material is much more dense rock. 
B) The material is much less dense rock. 
C) The material is an underground ore. 
D) The material is composed of mantle. 
A) The material is much more dense rock. 
B) The material is much less dense rock. 
C) The material is an underground ore. 
D) The material is composed of mantle.

Question 18

If you measure the magnetization of an area of igneous rocks and find a large negative anomaly,what does that imply about the rocks?

Accepted Answer

A) They were formed during a time of normal polarity of the magnetic field. 
B) They were formed during a time of reversed polarity of the magnetic field. 
C) They were formed on the ocean floor where the rocks are closer to the core. 
D) They were formed on the continental crust in a complex pattern of magnetization. 
A) They were formed during a time of normal polarity of the magnetic field. 
B) They were formed during a time of reversed polarity of the magnetic field. 
C) They were formed on the ocean floor where the rocks are closer to the core. 
D) They were formed on the continental crust in a complex pattern of magnetization.

Question 19

A mountain range made of granite would produce a(n)________ gravity anomaly.

Accepted Answer

A) positive 
B) negative 
C) isostatic 
D) magnetized 
A) positive 
B) negative 
C) isostatic 
D) magnetized

Question 20

The following picture is a gravity map of the United States.What do the dark gray regions mean in terms of the density of the material below?

Accepted Answer

A) high-density rock 
B) low-density rock 
C) rock of high magnetization 
D) rock of low magnetization 
A) high-density rock 
B) low-density rock 
C) rock of high magnetization 
D) rock of low magnetization

Exam 27: the Earths Interior, revisited: Seismic Layering, gravity, and the Magnetic Field

What causes the velocity of a P-wave to speed up when it enters the inner core?

The graph below shows the change in velocity of seismic waves with depth in the crust.Why does the velocity of the P-wave drop drastically at the core-mantle boundary?

You are studying the seismic data from Mars when you notice that there are no S-waves recorded from 130° through 180° on the opposite side of the planet.What does this information tell you about the interior of Mars?

If a P-wave is traveling through the Earth and encounters a molten magma chamber,what will happen to the velocity of the P-wave?

Using the graph below,why is the outer core liquid,but the inner core solid?

If an S-wave is traveling through rock when it encounters a magma chamber,the S-wave will ________.

If a P-wave is traveling through sandstone and then encounters peridotite,the P-wave will ________.

Earth's gravity is best represented by an equipotential surface that contains bumps and depressions where areas of higher or lower gravity appear over the Earth.This representation is called the ________.

Which layer of the Earth has the highest density?

The core consists of two layers: the ________ inner core and ________ outer core.

Why would the gravity anomaly over a deep-ocean trench be negative?

If a ship weighs 52,000 tons and is in isostatic equilibrium when 6,000 tons of cargo is added,what is the total mass of water that will be displaced by the ship after the cargo is added?

In the following graph,why does the line for S-waves NOT appear in the outer core?

The time it takes for a seismic wave to travel from the focus to a seismometer is called the ________.

Seismic waves travel ________ in solids than in liquids;however,unlike P-waves,S-waves ________ travel through liquids.

Why are magnetic anomalies of continental crust so much more complicated than those of oceanic crust?

If a gravity anomaly is negative,what does that imply about the material underground?

If you measure the magnetization of an area of igneous rocks and find a large negative anomaly,what does that imply about the rocks?

A mountain range made of granite would produce a(n)________ gravity anomaly.

The following picture is a gravity map of the United States.What do the dark gray regions mean in terms of the density of the material below?

Cosmology and the Birth of Earth

Journey to the Center of the Earth

Drifting Continents and Spreading Seas

The Way the Earth Works: Plate Tectonics

Patterns in Nature: Minerals

Up From the Inferno: Magma and Igneous Rocks

Pages of Earths Past: Sedimentary Rocks

Metamorphism: a Process of Change

The Wrath of Vulcan: Volcanic Eruptions

A Violent Pulse: Earthquakes

Crags,cracks,and Crumples: Crustal Deformation and Mountain Building

Deep Time: How Old Is Old

A Biography of Earth

Squeezing Power From a Stone: Energy Resources

Riches in Rock: Mineral Resources

Unsafe Ground: Landslides and Other Mass Movements

Streams and Floods: the Geology of Running Water

Restless Realm: Oceans and Coasts

A Hidden Reserve: Groundwater

An Envelope of Gas: Earths Atmosphere and Climate

Dry Regions: the Geology of Deserts

Amazing Ice: Glaciers and Ice Ages

Global Change in the Earth System

Introducing Rocks

a Surface Veneer: Sediments and Soils

the Rock Cycle in the Earth System

Memories of Past Life: Fossils and Evolution

Ever-Changing Landscapes and the Hydrologic Cycle

Filters

The core consists of two layers: the inner core and outer core.

Seismic waves travel in solids than in liquids;however,unlike P-waves,S-waves travel through liquids.