1. Investigation 2 Facts The Interior of the Earth

2. Fault A break in Earth ’ s crust where rock on one side moves in relation to rock on the other side.

3. Seismic wave A vibration in Earth ’ s crust, caused by the release of energy at a fault.

4. Point of origins Focus The point inside Earth where a seismic wave begins. Epicenter The point of the Earth surface directly above the focus.

5. Measuring Magnitude Richter Scale Charles Richter developed a scale that uses the size of waves to determine the magnitude of an earthquake.

7. Seismograph Any of various instruments for measuring and recording the vibrations of earthquakes. the

8. Seismologist Scientist that studies seismic waves.

9. Tsunami An unusually large sea wave produced by a seaquake or undersea volcanic eruption.

10. Types of Seismic Waves Body Waves Compressional Wave (P-Wave) Primary Shear Wave (S-Wave) Secondary Surface Waves Rayleigh Wave named for John William Strutt, Lord Rayleigh. He mathematically predicted this kind of wave in 1885 Love Wave named after A.E.H. Love, a British mathematician who discovered it in 1911.

12. Investigation 2 Vocabulary Seismograph Shadow zone Physical model Conceptual model Mathematical model Numerical Model Average wave speed Compressional wave (p-wave) Shear wave (s-wave) Seismic wave Boundary Refraction Richter scale Magnitude

13. Body Waves Compressional Wave Energy is compressed or squeezed together then released in a straight pathway. Able to flow through solids, liquids, and gases Shear Wave The second wave you feel in an earthquake. An S wave is slower than a P wave and can only move through solid rock.

14. Surface Waves Rayleigh Wave A Rayleigh wave rolls along the ground just like a wave rolls across a lake or an ocean. Because it rolls, it moves the ground up and down, and side-to- side in the same direction that the wave is moving. Love Wave It's the fastest surface wave and moves the ground from side-to- side. http://www.geo.mtu.edu/UPS eis/waves.html

15. Refraction Wave refraction: When a set of waves cross a boundary (change of material in the Earth ’ s surface) causing it to change speed and direction.

16. Average Wave Speed The average speed a wave travels in a matter of seconds. Ave. wave speed= distance (cm) time (s)

17. Seismograph Records the magnitude of each wave as a passes a seismograph station.