Below the Earth's Surface

Question 1

What are the 4 main layers of the Earth?

Answer 1

Inner Core, Outer Core, Mantle, Crust

Question 2

What are the two parts of the crust?

Answer 2

Continental and Oceanic crust

Question 3

Describe the Continental Crust

Answer 3

Thick (~10-70km)
Rich in silicates and aluminium minerals (sial)

Question 4

Describe the Oceanic Crust

Answer 4

Thin(~5km), more dense with composition similar to basalt
Rich in magnesium and silicate minerals (sima)

Question 5

Order the layers from thinnest to thickest

Answer 5

Crust, Inner Core, Outer Core, Mantle

Question 6

Describe the Mantle

Answer 6

Thickest layer of the Earth.
Molten rock with convection currents in the upper-mantle.
High temperature and pressure.

Question 7

What is the core as a whole mostly composed of?

Answer 7

Iron, nickel and cobalt

Question 8

Describe the Outer Core

Answer 8

Liquid.
Iron, nickel and some lighter elements.
Convection currents in the outer core may be responsible for Earth’s magnetic field.

Question 9

Describe the Inner Core

Answer 9

Solid.
Mostly iron with some nickel.

Question 10

What are the 3 earthquake depths?

Answer 10

0-70km Shallow
70-300km Intermediate
300-700km Deep

Question 11

Name at least 2 ways we know about the composition of the Earth’s interior? (Bonus points for all of them)

Answer 11

Drilling and mining.
Volcanic eruptions.
Earth’s magnetic field.
Measuring mass and density of the Earth.
Study of meteorites.
Seismic waves.

Question 12

What happens to seismic waves when they travel through materials of different densities.

Answer 12

They refract.

Question 13

Describe the refraction of seismic waves in different densities.

Answer 13

A seismic wave moving from a slower-velocity layer to a higher-velocity layer is refracted up. The reverse occurs when a wave passes from a higher-velocity to a slower-velocity layer.

Question 14

How can the reflection of seismic waves be used?

Answer 14

To determine the depth of a layer in the Earth.