Earth Structure

Question 1

Do we have any direct observation of the interior structure of the Earth?

Answer 1

No

Question 2

How to we know what is below the Earth’s crust?

Answer 2

Indirect observations

Question 3

What are 2 kinds of indirect observations we use to study the interior structure of the Earth?

Answer 3

Seismic Waves

Discontinuities

Question 4

Describe Seismic Waves

Answer 4

How we measure earthquakes
Surface waves: travel across whole earth
Body waves: travel through earth

Question 5

What are discontinuities?

Answer 5

Boundaries between layers

Question 6

List the compositional layers of the Earth’s interior according to density

Answer 6

Crust = least dense
Mantle = more dense
Core = highest density

Question 7

What are the final layers and character of the Crust?

Answer 7

Crust=
Crust - Solid
Uppermost Mantle - Solid

Question 8

What are the final layers and character of the Mantle?

Answer 8

Mantle=
Asthenosphere - Plastic
Upper Mantle - Solid
Lower Mantle - Solid

Question 9

What are the final layers and character of the Core?

Answer 9

Core=
Outer Core - Liquid
Inner Core - Solid

Question 10

What is a plastic?

Answer 10

A malleable solid (changes shape when pressure is applied)

Question 11

What is Moho Discontinuity (ie Mohorovicic)?

Answer 11

In the Lithosphere, the boundary between the crust and the uppermost mantle

Question 12

Where is the Lithosphere?

Answer 12

The Lithosphere sits on the asthenosphere, floating along

Question 13

What are the 2 types of crust and how do they differ?

Answer 13

Oceanic- thinner and denser (floats lower)

Continental- less dense and thicker (floats higher)

Question 14

What is Isostatic Adjustment?

Answer 14

When the crust thickens, gets heavier and sinks (mountain building) or when the crust thins, gets lighter and floats (mountain wears away) -made possible by the plasticity of the Asthenosphere, causing Lithosphere to get pushed down and rise back up as weight changes on top

Question 15

What is a Geological Process/Cycle?

Answer 15

The set of processes that lead to changes in characteristics of the earth/changes the surface of the earth

Question 16

What are the 2 Geological Processes?

Answer 16

Exogenous and Endogenous

Question 17

Describe Exogenous

Answer 17

Process occurring outside the earth

Question 18

Describe Endogenous

Answer 18

Process occurring from within the earth

Question 19

How old is the Earth?

Answer 19

4.6 billion years old = “Incomprehensible”

Question 20

What are the 2 ways to measure time?

Answer 20

Absolute and Relative

Question 21

What is Absolute Time?

Answer 21

How long something has been in existence (ie Radiometric dating)

Question 22

What is Relative Time?

Answer 22

How old something is in relation to something else (ie Superposition, Relative dating)

Question 23

What is Uniformatism?

Answer 23

The same physical processes active in the environment today have been operating throughout geologic time. The slow application of a process making small changes over long periods of time.

Question 24

What is Catastrophism?

Answer 24

Sudden, large changes in a short period of time (pertains to more non-scientific understandings of the world)