1. Earthquakes

3. What is an earthquake?
The shaking and trembling that results from the sudden movement of part of the Earth’s crust.

4. Fault
A break or crack in Earth’s crust along which movement has occurred.

5. Focus / Epicenter
Focus: The point beneath the earth’s surface where the rocks break and move.
Epicenter: The point on the earth’s surface directly above the focus

6. Seismic Waves
P-Waves (Primary Waves): These compression waves travel the fastest and can pass through solids, liquids and gases.
P-wave movie

7. S-Waves
(Secondary Waves) These waves travel slower than P-waves and can travel through solids, but not liquids.
S-wave movie

8. L-Waves (Surface Waves)
The slowest and most damaging wave that moves through the earth like an ocean wave.
L-Wave Movie

9. Seismograph
This is an instrument detects and measures earthquakes.

10. Tsunamis
Also known as Tidal waves, these are ocean waves created by earthquakes.