Chapters 2

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Chapters 2 3

• Earthquakes Volcanoes

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2.1 Earths Crust in Motion

• Faults
• Caused by plate movement
• Build up of stress leads to breaking crust
• Occurs at plate boundaries
• 3 types of faults strike-slip, normal reverse

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2.1 Earths Crust in Motion

• Normal Fault
• Tension forces stretch rock
• 1 block of rock above other below

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2.1 Earths Crust in Motion

• Reverse Fault
• Compression forces push rock together
• Rock slides up over

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2.1 Earths Crust in Motion

• Strike-slip Fault
• Caused by shearing force
• Rocks on either side slip past each other

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Fault type lab

• What does the chocolate layer represent?
  Caramel? Nougat?
• 2. Break crust w/ fingernail and gently pull
  apart. What type of fault does this represent?
  What kind of stress was applied?

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Fault type lab

• Model a strike-slip fault. Describe what you
  did. What type of force was applied?
• 4. Push the candy bar together. What type of
  fault is created by this action?

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2.2 Measuring Earthquakes

• Earthquake
• Sudden motion of
  crust as stuck plates
  release
• Focus
• Point below Earths surface where crust breaks
  from stress

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2.2 Measuring Earthquakes

• Epicenter
• Point on Earths surface right above focus of
  earthquake

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2.2 Measuring Earthquakes

• Seismic Waves
• Vibrations produced by earthquakes
• Measured on a seismograph

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2.2 Measuring Earthquakes

• P-waves (primary)
• 1st to be sent out from focus
• Travel fast
• Push pull motion
• S-waves (secondary)
• Reach surface after P-waves
• Side to side motion

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2.2 Measuring Earthquakes

• Surface waves
• Created when P S waves reach surface
• Move more slowly
• ground roll

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2.2 Measuring Earthquakes

• Quake Severity
• Different ways to express
• Magnitude
• Richter scale Moment magnitude scale
• Based on size of seismic waves (energy of quake)

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2.2 Measuring Earthquakes

• Mercalli Intensity Scale
• Based on damage
• Not as scientific