Earthquakes –What is it?
• Shaking and trembling of the earth’s crust.
• About _________occur every day or one every ____seconds
• Caused by plates sliding beside each other
• __________________ - earthquake on the ocean floor: causing waves to become greater than
20 meters high
A strike-slip earthquake:
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Normal plate movement:
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A thrust earthquake:
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Seismic Waves:
The three main types of seismic waves are:
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P Waves:
• Primary waves
• Arrive first at the epicenter
S Waves:
• Secondary waves
• Move in up-down motion
L Waves:
• Slowest moving seismic waves
• Travel on top of Earth’s surface
Measuring Earthquakes:
• _________________________-measures and detects seismic waves
• _________________________- a scale that allows scientists to determine earthquake strength based on many readings
• 1-10 levels at which an earthquake is measured Above a 6 is very destructive
• _______________ - aboveground of origin; most violent shaking occurs at the epicenter

What influences the amount of damage an earthquake causes?
 magnitude of the earthquake (how strong and fast the seismic waves are)
 distance of location from ____________________________________________________
 type of movement of the plates or along fault
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_________________________________________ (loose, solid, flexible, stiff)
 construction type and _______________________________