1. Chapter 12-2
Studying Earthquakes

2. Seismology Seismology – the study of earthquakes
Helps to study the Earth’s interior

3. Seismograph – instrument used to detect vibration in the ground
Track vertical and horizontal movement

4. 4

5. 5

6. Seismogram – traces of earthquake motion that is recorded by seismograph
1st – P waves
2nd – S waves
3rd – Surface waves

7. Locating an Earthquake
To determine the distance to an epicenter
Determine the difference between P and S waves
Longer lag time = further away

8. Magnitude Magnitude – measure of the strength of an earthquake
Ground motion
Richter Scale

9. 9

10. 10

11. 11

12. 12

16. Moment magnitude scale – more accurate
1. Size of the area the fault moves
2. Distance fault moves
3. Rigidity of the rocks

17. Intensity
Intensity – measure of the amount of damaged caused by an earthquake
Modified Mercalli Scale