Tectonic Processes + Hazards

Question 1

What 3 layers is the Earth divided into?

Answer 1

• Crust
• Mantle
• Core

Question 2

What is the crust?

Answer 2

The outermost layer of the Earth, rigid + thin, where we live

Question 3

What are the two types of crust?

Answer 3

• Continental crust

- Oceanic crust

Question 4

What is sial?

Answer 4

Rock composed of silica + aluminium

Question 5

What is siam?

Answer 5

Rock composed of silica + magnesium

Question 6

What is the thickness of the continental crust?

Answer 6

30-70km

Thicker

Question 7

What is the thickness of the oceanic crust?

Answer 7

6-10km

Thinner

Question 8

What is the age of the continental crust?

Answer 8

Over 1,500 mill yrs

Older

Question 9

What is the age of the oceanic crust?

Answer 9

Under 200 mill yrs

Younger

Question 10

What is the density of the continental crust?

Answer 10

Average 2.6

Lighter/less dense

Question 11

What is the density of the oceanic crust?

Answer 11

Average 3.0

Heavier/more dense

Question 12

What is the composition of continental crust?

Answer 12

• Many types of light rock

- Mostly granite: sial

Question 13

What is the composition of oceanic crust?

Answer 13

• Few types of dark rock

- Mostly basalt: sima

Question 14

Where is continental crust located?

Answer 14

Base of continents

Question 15

Where is oceanic crust located?

Answer 15

Base of ocean floor

Question 16

What is the mantle?

Answer 16

The middle layer of the Earth, between the crust + the core

Question 17

What is the thickness of the mantle?

Answer 17

Approx 2,900km

Question 18

What is the density of the mantle?

Answer 18

Dense

Question 19

What is the temperature of the mantle?

Answer 19

1000C - 4000C

Question 20

What is the composition of the mantle?

Answer 20

• Semi-molten rock

- Largely silicate + rich in magnesium, iron + calcium

Question 21

What is the core?

Answer 21

The inner layer of the Earth (at centre)

Question 22

What is the core split into?

Answer 22

• Inner core

- Outer core

Question 23

What is the density of the core?

Answer 23

Most dense (nearly twice as dense as the mantle)

Question 24

What is the temperature of the core?

Answer 24

Hottest layer

Can reach 6,200C

Question 25

What is the thickness of the outer core?

Answer 25

Approx 2200km

Thicker than the inner core

Question 26

What is the thickness of the inner core?

Answer 26

Approx 1,250km

Thinner than the outer core

Question 27

What is the composition of the outer core?

Answer 27

Semi-molten iron + nickel

Question 28

What is the composition of the inner core?

Answer 28

Solid iron + nickel

Question 29

What creates the Earth’s magnetic field?

Answer 29

Movement of the semi-molten mantle in convection currents

Question 30

Which layer of the Earth is not part of any sphere?

Answer 30

Core

Question 31

What are the spheres within the Earth?

Answer 31

Areas within the Earth

• Lithosphere
• Asthenosphere
• Mesosphere

Question 32

What is the lithosphere + its properties?

Answer 32

Cool, rigid layer of rock made up of the crust + upper mantle

• Approx 100km thick
• Divided into plates
• Floats on asthenosphere

Question 33

What is the asthenosphere + its properties?

Answer 33

Hot, semi-molten layer made up of the rest of the upper mantle

• Approx 180km thick
• Can flow when subjected to high heat + pressure

Question 34

What is the mesosphere + its properties?

Answer 34

Hot, semi-molten layer made up of the lower mantle

• Approx 350km thick
• Can flow but much less (under higher pressure so much more rigid)