Triangulation

Question 1

Explain how to read a seismogram.

Answer 1

The earthquake happens at time 0. The P waves arrive first, then the S waves then later on the surface waves.

Question 2

What does the S-P interval tell a seismologist?

Answer 2

How far away the earthquake was.

Question 3

What is the amplitude of a seismic wave?

Answer 3

The amount the ground moves as the wave passes by.

Question 4

What does amplitude look like on a seismogram.

Answer 4

The height of the wave from resting.

Question 5

What is triangulation used for?

Answer 5

To locate the epicentre of an earthquake.

Question 6

What are the steps of triangulation?

Answer 6

• Find the S-P time
• Use a graph to find the distance from the epicentre
• Using the scale on the map convert actual distance to map distance
• Draw a circle on the map using the map distance as your radius and the seismograph location as the centre
• Where the three circles cross is the location of the epicentre

Question 7

What is S-P time?

Answer 7

The time difference between the arrival o the primary and secondary waves.