Seismic waves

Question 1

Primary waves

Answer 1

Fastest - compressional vibrating in the direction they travel

Question 2

Secondary waves

Answer 2

Half the speed of P-waves and shear rock by vibrating at right angles to the direction of travel

Question 3

Surface waves

Answer 3

Travel slowest and near to ground surface. Some shake the ground at right angles to the direction of wave movement. Some have a rolling motion that produces vertical ground movement

Question 4

How do they cause earthquakes?

Answer 4

When plates jerk past each other due to tension seismic waves (vibrations) are sent out. These vibrations are the eathquake

Question 5

Where do they spread out from

Answer 5

The focus