A powerpoint by a student.

1. Earthquakes And Tsunamis

2. Earthquakes

3. An earthquake the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.

4. The largest earthquakes in historic times have been of magnitude slightly over 9, although there is no limit to the possible magnitude.

5. The most recent large earthquake of magnitude 9.0 or larger was a 9.0 magnitude earthquake in Japan in 2011 (as of March 2011), and it was the largest Japanese earthquake since records began.

6. Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane.

7. An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock.

8. Tsunamis

9. A tsunami , also called a tsunami wave train, and at one time incorrectly referred to as a tidal wave.

10. Tsunamis are a frequent occurrence in Japan; pproximately 195 events have been recorded. Owing to the immense volumes of water and the high energy involved, tsunamis can devastate coastal regi

11. Tsunamis cause damage by two mechanisms : the smashing force of a wall of water travelling at high speed. And the destructive power of a large volume of water draining off the land and carrying all with it, even if the wave did not look large.

12. As the tsunami approaches the coast and the waters become shallow, wave shoaling compresses the wave and its velocity slows below 80 kilometres per hour (50 mph)

13. If the first part of a tsunami to reach land is called a drawback

14. A drawback occurs because the water propagates outwards with the trough of the wave at its front.

15. The End Omar Calleja 3.03