8.1 Earthquakes

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8.1 Earthquakes
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Chapter 8 Earthquakes
Earthquake -- the vibration of Earth produced by
the rapid release of energy
Focus -- the point within Earth where the
earthquake starts
Epicenter -- the location on the surface
directly above the focus
Fault -- fracture in Earth where movement has
occurred
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Focus, Epicenter, and Fault
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Slippage Along a Fault
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Causes of Earthquakes
? Elastic Rebound Hypothesis

• Rocks bend and stored energy builds up.
• Rocks break and slip. Rapidly releasing energy.
  (Earthquake)
• Rocks bounce back into original shape.

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Elastic Rebound Hypothesis
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Aftershocks and Foreshocks
aftershock -- small earthquake that follows
the main earthquake.
foreshock -- small earthquake that often comes
before a major earthquake
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Seismic Waves radiate from focus and transmit
energy.