P8.3.5

Question 1

What are the 4 components of our Earth’s structure?

Answer 1

Inner core - solid
Outer core - liquid
Mantle - almost solid
Crust - solid, what we live on

Question 2

What type of waves do earthquakes produce and how are they detected?

Answer 2

Seismic waves - used to detect the Earth’s structure

Seismometers

Question 3

What are the 2 types of seismic waves and their properties?

Answer 3

P - waves (primary) - longitudinal, can travel through solids and liquids
S - waves (secondary) - transverse, can’t travel through liquids

Question 4

Why do seismic waves take a curved path through the earth?

Answer 4

They bend due to the changing density.

Question 5

How do we know the outer core is liquid?

Answer 5

The S-wave shadow zone is large and shows that the S-waves cannot penetrate part of the centre of the Earth, and since they are transverse, they cannot travel through liquids.

Question 6

Why are there P-wave shadow zones?

Answer 6

P-waves travel faster in solids than liquids, when they enter the outer core, they refract and then refract when they leave, leaving a gap where there are no p-waves between those p-waves in the mantle and those coming from the outer core.

Question 7

What do faint P-waves tell us?

Answer 7

They are found in the P-wave shadow zone, they show us that the inner core is solid.