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# Sharon joji and rajat

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### Sharon joji and rajat

1. 1. earthquakes ! !! e m e Sav By Sharon and Rajat
2. 2. What is an Earthquake?Earthquakes: Vibrations (seismic waves)Earthquakeswithin Earth materials are produced by the rapidrelease of energy  Earth’s crust is in constant motion because of tectonic forces  Earth’s crust can store elastic energy  When forces exceed the elastic limits and structural strength of the rocks, the rocks will break and/or move producing vibrations that travel outward in all directions
3. 3. Earthquakeso The actual place underground where the rocks break producing vibrations is called the focuso The place on the surface directly above the focus is called the epicenter
4. 4. What types of forces are created?Compression Force: Force force pushing something together Makes a reverse fault
5. 5. What types of forces are created?Tension Force: Force stretching or pulling force Makes a normal fault
6. 6. What types of forces are created?Shear Force: Force a system of forces that operates against a body from different sides Makes a strike-slip fault
7. 7. http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
8. 8. http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
9. 9. What causes Earthquakes? when the Movement along faults: occurs energy exceeds the friction holding the sides of the fault together and is suddenly released .Movement of magma (volcanic) Volcanic eruptions
10. 10. Originate at the focus and travel outward in al Seismic Waves directions  Foreshocks: small earthquakes that come Foreshocks before a major earthquake  Aftershocks: Are adjustments in the crust Aftershocks after in earthquake o Smaller than main earthquake, but can cause as much or more damage. They can continue for weeks to months. Not every earthquake months produces aftershocks
11. 11. 3 Types of seismic Waves P waves (primary waves) Compressional wave  Particles move back and forth in the same direction as the wave  Travels the fastest  Can pass through solids and liquids (gases also)  Does not cause damage
12. 12. Types of Waves S wave (secondary wave, shear wave)  Particles move at right angles to the direction of the wave  Travels slower than P waves  Can pass through solids only  Does not cause damage
13. 13. Types of Waves L wave (long wave, surface wave, ground wave)  Particles move in elliptical orbit  Originates on the surface after the P and S waves go straight up from the focus and reach the surface  The L wave causes the damage and will be the strongest at the epicenter  Travels the slowest
14. 14.  Earthquake Safety Protect yourself from falling objects (GET UNDER SOMETHING) or stand in a hallway or doorway (watch out for a swinging door) Do not try to go outside during the earthquake After the earthquake and before the aftershocks, go outside Do not return to the building until it has been inspected
15. 15. Why japan is stillalive after the massiveearthquake
16. 16. Sharon and Rajat