1. Earthquakes

2. What is an earthquake?
Shaking and trembling that results from the movement of rock beneath Earth’s surface

3. Three Types of Faults Strike-Slip Reverse (FDR) Normal (FUN)
Form depending on type of plate motion and complex reaction of earth’s lithospheric blocks
Strike-slip
Normal
Thrust
Normal
(FUN)

4. What causes earthquakes?
The movement of the plates creates stress (the force that changes a rock’s shape or volume)
These stresses (shearing, tension, and compression) work over millions of years to make rocks bend or snap violently.

5. Elastic Rebound – deformed rock goes back to its original shape

6. Focus –. point inside the Earth where an
Focus – point inside the Earth where an earthquake begins Epicenter – point on Earth’s surface above focus

7. How Seismographs Work
the pendulum remains fixed as the ground moves beneath it

8. Typical Seismogram

9. Primary Waves (P Waves)
A type of seismic wave that compresses and expands the ground
The first wave to arrive at an earthquake

10. Secondary Waves (S Waves)
A type of seismic wave that moves the ground up and down or side to side

11. Comparing Seismic Body Waves

12. Surface Waves Move along the Earth’s surface
Produces motion in the upper crust
Motion can be up and down
Motion can be around
Motion can be back and forth
Travel more slowly than S and P waves
Most destructive

13. How do scientists calculate how far a location is from the epicenter of an earthquake?
Scientists calculate the difference between arrival times of the P waves and S waves
The further away an earthquake is, the greater the time between the arrival of the P waves and the S waves

14. Locating Earthquakes

15. Locating Earthquakes

16. Locating Earthquakes

17. How are Earthquakes Measured? Richter Scale

18. How are Earthquakes Measured? Mercalli Intensity Scale
Click Link for Interactive Demo

19. Earthquake Waves & Earth’s Interior

20. Seismic Waves in the Earth

21. Tsunamis https://www.youtube.com/watch?v=dJBS94GVyuo

22. Formation of a tsunami

23. Tsunami Warning System