Chapter 8 Sections 1-4

# Chapter 8 Sections 1-4

## Chapter 8 Sections 1-4

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##### Presentation Transcript

1. Chapter 8Sections 1-4 By: Kelsey Garrison Brittany Ramsey

2. Seismology • The study of earthquakes. The scientists who study the earthquakes are called seismologists.

3. Fault • A break in the Earth’s crust along which blocks of the crust slide relative to one another. Earthquakes occur along faults due to this sliding.

4. Deformation • The change in the shape of a rock in response to stress. • Rock along a fault deforms mainly in two ways-in a plastic manner, like a piece of molded clay, or in a n elastic manner, like a rubber band.

5. Elastic rebound • The sudden return of elastically deformed rock to its original shape. • Elastic rebound occurs when more stress is applied to rock than the rock can withstand.

6. Seismic waves • Waves of energy that travel through the earth. • Different types of seismic waves travel at different speeds and move the materials that they travel through differently.

7. P waves • Travel through solids, liquids, and gases-fastest seismic waves. Because p waves are always the first seismic waves to be detected, they are also called primary waves.

8. S waves • Shear waves-second fastest seismic wave. Also, S waves are slower than P waves and always arrive second; thus, they are also called secondary waves.

9. Seismographs • Are instruments located at or near the surface of the earth that record seismic waves.

10. Seismogram • A tracing of earthquake motion created by a seismograph. • Seismologists use seismograms to calculate when an earthquake started.

11. Epicenter • Thon the Earth’s e point surface directly above an earthquakes starting point. • The most common method by which seismologists find an earthquake’s epicenter is the

12. Focus • The point inside the Earth where an earthquake begins.

13. Gap hypothesis • States that sections of active faults that have had relatively few earthquakes are likely to be the sites of strong earthquakes in the future.

14. Seismic gaps • The areas along a fault where relatively few earthquakes have occurred.

15. Moho • A place within the Earth where the speed of seismic waves increases sharply. It marks the boundary between the Earth’s crust and mantle.

16. Shadow zone • An area on the Earth’s surface where no direct seismic waves from a particular earthquakes can be detected.