An earthquake is a shaking of the Earth’s crust cause by a release of energy. Earthquakes happen...
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Transcript of An earthquake is a shaking of the Earth’s crust cause by a release of energy. Earthquakes happen...
Earthquakes
An earthquake is a shaking of the Earth’s crust cause by a release of energy.
Earthquakes happen because – eruption of a volcano, collapse of a cavern, impact of a meteor
Most major earthquakes are caused by the movement of two faults (Fault a break in the lithosphere {crust} between two lithospheric plates)
Causes of Earthquakes
The point where the first movement occurs
Focus ……
The point on Earth’s surface directly above the focus
Epicenter…..
1. Body waves waves that travel from the focus of the earthquake through the Earth
Waves
P waves primary waves, compressional waves squeeze and stretch rock materials as they pass through Earth; p-waves can travel through any material….solid rock, magma, ocean water, air
P-waves
S waves secondary waves, shear waves cause particles of rock material to move at right angles to the direction in which the waves are traveling; s-waves can ONLY travel through solid material, NOT liquids or gases
S-Waves
Earthquake waves that travel along Earth’s surface.
Love waves cause particles of material to move from side to side, in a direction PERPENDICULAR to the waves’ direction of travel
Rayleigh waves travel slower than Love waves; material moves in a elliptical pattern
Surface Waves
Seismograph
Detects and records waves produced by earthquakes
Seismograph
Strength of an earthquake
Charles Richter (1935) Richter Scale ; each level on the scale is 31 times greater than the level before it
Magnitude
Ground shaking and foundation failure (buildings falling over, completely collapsing)
Liquefaction loose soil that moves like a liquid instead of a solid
http://www.youtube.com/watch?v=j0sLyJpfTE8
Aftershocks smaller earthquakes that follow after the main earthquake
http://www.youtube.com/watch?v=Z7eABGpOHv8
Fire
http://www.youtube.com/watch?v=f5xt8oQTApE
Tsunami underwater earthquakes that create huge ocean waves
http://www.youtube.com/watch?v=k8IAgUNr6x4
Earthquake Hazards……