WAVES

1
WAVES

• Vibrations that are caused by bursts of energy

2
THREE MAIN TYPES

• 1. Compression Waves (P waves)
• Squeeze together and pull apart like an
• accordion
• 2. Shear Waves (S waves)
• Wiggle back and forth like a snake
• 3. Surface Waves

3
P Waves

• P stands for pressure
• P stands for primary
• fastest seismic waves
• travel through solids like rock
• travel through liquids a stone in a pond
• travel through gas your voice

4
S Waves

• S stands for secondary
• S stands for shear
• slower waves, arrive second, after P
• can only travel through solids

5
Seismic waves

• Both P waves and S waves are created
• during an earthquake
• Seismographs around the world detect
• waves
• The location and type of wave tells
• seismologists what the interior of the
• earth must be like

6
Surface Waves

• Move the ground up and down in circles
• feel like a roller coaster
• Move the slowest, cause the most
• earthquake damage

7
Wave Refraction

• Waves travel at different speeds through
  different densities
• Waves travel faster through solids than gases
• This is why you should keep your ear to the
  ground!
• P Waves travel faster as they go down, then curve
  upward as they go through the mantle

8

• Draw P and S waves on your 3 D Model of Earths
  interior.

9
Earths Interior

• Shadow Zone - proves the center of the Earth
  must be a different density
• Magnetic field proves center (core) is iron
• Both P and S waves go through the mantle - so it
  must be solid
• Only P waves go through core - so iron must be
  melted
• Very center of core seems to be solid