Earthquakes are caused by the movement of tectonic plates underneath the earth's surface. When the plates shift and release stress, seismic waves propagate outward from the epicenter. Scientists measure the intensity of earthquakes using the Richter scale. During an earthquake, it is important to drop, cover, and hold on underneath sturdy furniture to protect oneself from falling debris.

1. Earthquake Presented by:ryan ali m. catagaI-faith

2. Earthquakes are the shaking, rolling or sudden shock of the earth’s surface. They are the Earth's natural means of releasing stress. Earthquakes can be felt over large areas although they usually last less than one minute. Earthquakes cannot be predicted, although scientists are working on it.

3. There are about 20 plates along the surface of the earth that move continuously and slowly past each other. When the plates squeeze or stretch, huge rocks form at their edges and the rocks shift with great force, causing an earthquake. Ex: pencil test

4. As the plates move they put forces on themselves and each other. When the force is large enough, the crust is forced to break. When the break occurs, the stress is released as energy, which moves through the Earth in the form of waves, which we feel and call an earthquake.

5. A fault is an area of stress in the earth where broken rocks slide past each other, causing a crack in the Earth's surface. There are 4 major types of faults which are as follows: dip-slip normal, dip-slip reverse, strike-slip, and oblique-slip.

6. Dip-SlipNormal Fault

7. Dip-Slip Reverse Fault

8. Strike - Slip Fault

9. Oblique - Slip Fault

10. The plate tectonic theory is supported by a wide range of evidence that considers the earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another.

11. The plates are all moving in different directions and at different speeds. Sometimes the plates crash together, pull apart or sideswipe each other. When this happens, it commonly results in earthquakes.

12. A seismograph is an instrument used for recording the intensity and duration of an earthquake.

13. A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage.

14. Tidal waves vs. Tsunamis tidal waves tsunamis

15. Important Terminologies: EPICENTER - The point on the earth's surface directly above the source of the earthquake. SEISMIC WAVES - The energy created by the quake that travels in waves from the epicenter, where they are the strongest.

16. RICHTER SCALE - A measurement of an earthquake's intensity. - Each one-point increase on the scale indicates ten times the amount of shaking and 33 times the amount of energy. - The energy released by a large earthquake may be equal to 10,000 times the energy of the first atomic bomb.

17. Richter Scale 4 - Minor Earthquake 5 - Moderate Earthquake 6 - Strong Earthquake 7 - Major Earthquake 8 - Great Earthquake

20. Stay indoors until the shaking stops.

21. Stay away from windows.

22. If you’re in bed, hold on and stay there, protecting your head with a pillow.

23. If you’re outdoors, find a clear spot away from buildings, trees and power lines. Then, drop to the ground.

25. Inspect your home for damage.

26. Eliminate fire hazards, so turn off the gas if you think its leaking.

27. Expect aftershocks.