1. Nature and Distribution

Question 1

Focus depth

Answer 1

Friction along margins builds stresses in the lithosphere
Faults send a series of seismic shockwaves to the surface

Point where pressure is released is the focus and point immediately above that in earth’s surface is epicentre

Question 2

Focuses

Answer 2

Shallow focus (0-70km deep)- tend to cause greatest damage and 75% of all earthquake energy released

Intermediate focus: (70-300km deep)

Deep focus (300-700km deep)- Tend to be higher magnitude but cause less damage as shockwaves have to travel further reducing power

Question 3

Constructive margin

Answer 3

Tend to be close to the surface and narrowly concentrated

Lowest magnitude, potentially destructive due to shallow focus

Question 4

Destructive

Answer 4

Subduction of plate causes massive pressure to build up
Creates deep and shallow focus earthquakes
Most powerful

Question 5

Conservative

Answer 5

Narrow zone of shallow depth earthquakes which can be very destructive and high magnitude

Question 6

Intra-plate

Answer 6

Occur away from plate boundaries and associated with reactivation of old fault lines
Human activities such as mining and fracking can cause minor earthquakes

Question 7

Rate of plate movement

Answer 7

Tectonic plates move in relation to each other at different rates
1-15cm per year
No relationship between rate of movement and magnitude