Earthquakes

1
Earthquakes

• Section 17.2

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Earthquakes

• Shaking of the Earths crust caused by a release
  of energy
• Build-up of stress
• Stress overcomes friction
• Plates slip (EQ)
• Land snaps back into original shape

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3. Earthquakes

• Focus point UNDERGROUND where movement starts
• Epicenter point ON THE SURFACE directly above
  focus

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3. Earthquakes

• Seismic Waves
• Body Waves
• P-Waves
• aka Primary Waves
• Compressional wave movement
• Travel through solids, liquids, and gasses

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3. Earthquakes

• Seismic Waves
• Body Waves
• S-Waves
• aka Secondary Waves
• Arrive second, slower than p-waves
• Side-to-side wave movement
• Travel through solids ONLY

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3. Earthquakes

• Seismic Waves
• Surface Waves
• L-Waves
• aka Land Waves or Surface Waves
• Last waves to occur
• Cause most damage
• Rayleigh Waves or Love Waves

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3. Earthquakes
Body Wave Mantle Outer Core (liquid) Inner Core (solid)
P Speed up, refract Slow down Speed up
S Speed up, refract STOP
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3. Earthquakes
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3. Earthquakes
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Collapse Because Lack of Shear Walls
Loma Prieta, Ca 1986
San Fernando, Ca 1971
San Francisco