The Earth's Interior

Question 1

Why are there no P-waves or S-waves received in the P-wave shadow zone?

Answer 1

P-waves are refracted and S-waves are absorbed by Earth’s outer core.

Question 2

What makes up the lithosphere?

Answer 2

Crust and the upper mantle

Question 3

Miners dig into the Earth in search for precious rocks and minerals. In which layer is the deepest explorations made by miners?

Answer 3

Crust

Question 4

How do you compare the densities of the Earth’s crust, mantle, and core?

Answer 4

The mantle is less dense than the core but denser than the crust.

Question 5

The movement of the lithospheric plates is facilitated by a soft, weak and plastic-like layer. Which of the following layers is described in the statement?

Answer 5

Asthenosphere

Question 6

Alfred Wegener is a German scientist who hypothesized that the Earth was once made up of a single large landmass called Pangaea. Which of the following theories did Wegener propose?

Answer 6

Continental Drift Theory

Question 7

If you are a cartographer, what will give you an idea that the continents were once joined?

Answer 7

Shapes of the continents

Question 8

Which observation was NOT instrumental in formulating the hypothesis of seafloor spreading?

Answer 8

Identifying the location of glacial deposits

Question 9

As a new seafloor is formed at the mid-ocean ridge, the old seafloor farthest from the ridge is destroyed. Which of the stated processes describes how the oceanic crust plunges into the Earth and destroyed at the mantle?

Answer 9

Subduction

Question 10

What are the different layers of the Earth?

Answer 10

Crust
Mantle
Core

Question 11

In 1912, Alfred Wegener proposed a theory that the Earth is once a single landmass. What is the name of the Mesozoic supercontinent that consisted of all of the present continents?

Answer 11

Pangaea

Question 12

Who were the two scientists who proposed the theory of seafloor spreading in the early 1960s?

Answer 12

Harry Hess and Robert Dietz

Question 13

During the 1960s, scientists were already equipped with gadgets needed to explore the deep ocean. What discovery about the ocean floor is associated with the seafloor spreading?

Answer 13

The crust of the ocean is very young relative to the age of the crust
of the continents.

Question 14

If the Atlantic Ocean is widening at a rate of 3 cm per year, how far (in kilometers) will it spread in a million years?

Answer 14

30 kilometers

Question 15

Which of the following increases with distance from a mid-ocean ridge?

Answer 15

a. the age of oceanic lithosphere
b. the thickness of the lithosphere
c. the depth to the sea floor

Question 16

Which of the following can you infer from the continuous movement of the lithospheric plates over the asthenosphere?

Answer 16

The continents will not be located in the same place as they are now.

Question 17

If all the inner layers of the Earth are firm solid, what could have happened to Pangaea?

Answer 17

It remained as a supercontinent.

Question 18

Why does the oceanic crust sink beneath the continental crust at the subduction zone?

Answer 18

The oceanic crust is pushed from the ridge.

Question 19

The lithospheric plates are believed to be moving slowly. What is the driving force that facilitates this movement?

Answer 19

convection current in the mantle

Question 20

The _____ is the middle layer of the Earth. It makes most of the Earth’s
volume and mass.

Answer 20

mantle

Question 21

The _______ is made up of molten material and accounts for the Earth’s magnetic field.

Answer 21

outer core

Question 22

The _______ is the deepest layer of the Earth. It is made up of solid nickel and iron. The temperature in the inner core reaches as high as 5000oC

Answer 22

inner core

Question 23

properties of seismic waves are used by scientists to study the structure and composition of the Earth’s interior.

Answer 23

Speed
Refraction
Reflection

Question 24

The ___________ of Alfred Wegener states that the continents were once part of a large landmass called Pangaea which drifted away from each other. The continents moved away from each other towards their current positions.

Answer 24

Continental Drift Theory

Question 25

_____________ is believed to occur as hot magma rises at the rift in the mid-ocean ridge. This magma cools down and becomes the new seafloor as it pushes the former.

Answer 25

Seafloor spreading

Question 26

The ___________ is destroyed at the subduction zone and melts inside the mantle.

Answer 26

old seafloor

Question 27

The _________________ in the ocean floor support the Seafloor Spreading Theory.

Answer 27

age of rocks

magnetic stripes

Question 28

The ______________ helps explain the formation and destruction of the Earth’s crust and its movement over time.

Answer 28

Theory of Plate Tectonics

Question 29

Scientists believe that the plates’ movement is due to ___________ in the mantle.

Answer 29

convection currents

Question 30

soft, weak upper portion of the mantle where the lithospheric plates float and move around

Answer 30

Asthenosphere

Question 31

states that all the continents were once one large landmass that broke apart, and where the pieces moved slowly to their current locations

Answer 31

Continental Drift Theory

Question 32

current in the mantle because of the heat from the inner layers of the Earth, and is the force that drives the plates to move around

Answer 32

Convection Current

Question 33

the topmost, solid part of the Earth that is composed of several plates

Answer 33

Litosphere

Question 34

the moving, irregularly-shaped slabs that fit together to form the surface of the Earth

Answer 34

Lithospheric plates

Question 35

area in the middle of the ocean where a new ocean floor is formed when lava erupts through the cracks in the Earth’s crust

Answer 35

Mid ocean ridge

Question 36

the boundary that separates the crust and the mantle

Answer 36

Mohorovičić Discontinuity (Moho)

Question 37

the ability of solid to flow

Answer 37

Plasticity

Question 38

process by which new ocean floor is formed near the mid-ocean ridge and moves outward

Answer 38

Seafloor Spreading

Question 39

the process in which the crust plunges back into the Earth

Answer 39

Subduction

Question 40

branch of geology that deals with the movements that shape the Earth’s crust

Answer 40

Tectonics

Question 41

Elements of Crust

Answer 41

Oxygen
Silicon
Aluminum
Iron
Calcium
Sodium
Potassium
Magnesium 
Titanium
Hydrogen

Question 42

2 layers of crust

Answer 42

Upper layer: Granite

Lower layer: Basalt

Question 43

An S-wave shadow zone is formed as seismic waves travel through the Earth’s body. Which of the following statements does this S-wave shadow zone indicate?

Answer 43

The outer core is liquid