EARTHQUAKES

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EARTHQUAKES

• A Whole Lot of Shakin Goin On

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What is an earthquake?

• An earthquake is a shaking, rolling, or sudden
  shock of the earths surface.
• Large earthquakes cause violent motions of the
  earths surface.
• Few cause damage

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Why do earthquakes occur?

• The earths surface is made up of ridged plates
  that move slowly past one another. This motion
  squeezes and stretches rocks at the plates
  edges.
• If the force becomes too great, the rocks
  rupture (break) and shift, causing an earthquake.
• Most of these ruptures, or faults, lie beneath
  the surface. Some, such as the San Andreas Fault
  in California, can be seen on the surface.

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Where do earthquakes occur?

• Earthquakes occur in two large areas.
• The first is the circum-Pacific belt.
• The second is the Alpide belt.
• The circum-Pacific belt is often called the Ring
  of Fire because it experiences a lot of erupting
  volcanoes.
• The circum-Pacific belt has far more than
  three-fourths of the worlds earthquakes.

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Fault Lines
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What is a seismograph?

• A seismograph is an instrument that records the
  direction, intensity, and time of earthquakes.
• A seismograph can be linked to a computer to send
  information quickly.

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What is a Tsunami?

• A tsunami is a destructive wave caused by
  undersea earthquakes.
• It can also be called a tidal wave.

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How do we protect ourselves?

• Buildings are being designed that can withstand
  the destructive forces of earthquakes.
• They are built to handle the shaking of the
  earths surface.

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What can you do to protect yourself?

• When an earthquake starts, duck under the nearest
  sturdy structure. Protect your head and arms
  from falling objects.
• Stay under the structure until shaking stops.
• After shaking stops, exit your building and move
  away from electricity poles, fire, trees, and
  other unsafe objects. Always watch for falling
  debris.
• Fire is the greatest danger in an earthquake.
• Assemble in a safe area.

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THE END

• Thank you very much!!!!!