Presentation Schoolwires

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					  Earth’s Interior
• How do you think that
  scientists find out about
  places that they cannot
  easily visit, such as the
  Earth’s interior, the bottom
  of the ocean floor, other
  planets, etc.?
What is an earthquake???
                   1906
                   earthquake
                   damage at
                   Seventh and
                   Mission. "The
                   street was like
                   a heaving sea,
                   frozen in one
                   of its wildest
                   contortions."
 What
makes
earth-
quakes
occur?
Earthquakes and Seismic Waves
1. Information gathered
   about the interior
   comes from
   earthquakes
2. Seismic waves are
   shock waves produced
   by an earthquake
3. Waves are detected
   and recorded on a
   seismograph
Differences in Earth’s interior
cause waves to behave
differently- show interior is
made of layers with different
characteristics
         P Waves (Primary)
a. Move through solids (quickly),
   liquids (slowly), and gases (slowest)
b. Move with a push-pull motion
c. Fastest waves
   S Waves (Secondary)
a. Move through solids only
b. Side-to-side motion
 Surface (Rayleigh) Waves
a. Move along the Earth’s surface
b. Churn over and under like rolling
   ocean waves
c. Waves that people feel when an
   earthquake occurs
       Surface (Love) Waves
•   Move along the Earth’s surface
•   Make flattened round-and-round motions
•   Waves that people feel when an
    earthquake occurs- often responsible for
    making buildings collapse
http://neic.usgs.gov/neis/eq_depot/2
  002/eq_021103/ak2002sw_d.gif

				
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posted:12/20/2011
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