Earthquakes

1. An instrument that detects and records earthquake vibrations.
8. At a ____ fault boundary, two plates move past and away from each other.
9. The point on the surface of the earth directly above the focus of an earthquake.
10. The cracks or breaks in the earth's crust. This is where the plates that make up the earth's crust rub against each other.
12. The Energy released from earthquakes is felt as large ____.
14. These often follow an earthquake.
15. At a ____ boundary, plates move towards each other.
16. This moves, in the form of vibrations, in all directions from the focus of an earthquake.
17. Most earthquakes occur along ____ lines, or lines where tectonic plates meet.

2. A scale that usually ranges from 1 to 9. This scale is used to indicate the amount of energy an earthquake releases.
3. At a ____ boundary, plates move away from each other.
4. The ____ or P waves of an earthquake are back-and-forth vibrations. A person who experiences an earthquake will feel this wave first.
5. A sudden shift or movement of the earth's crust.
6. An earthquake releases energy in the form of ____ waves.
7. An earthquake rated as 4 on the Richter scale is ___ times as powerful as one rated a 3.
10. The point underground at which an earthquake starts.
11. The ____ or L waves of an earthquake travel on Earth's surface.
13. The ____ or S waves of an earthquake are side-to-side vibrations.