seismic waves

• Seismic waves


  Waves that carry energy away from an earthquake and pass through the Earth
• 1. waves


  • Longitudinal waves
  • Can pass through solids and liquids
  • Travel faster than S-waves
• 1. waves


  • Transverse waves
  • Can only travel through solids
• How scientists determine the Earth's internal structure

  1. Detect seismic waves from earthquakes using seismometers

  2. Analyze patterns of P-waves and S-waves

  3. Identify shadow zones where waves cannot be detected

  4. Use this information to infer the composition of the Earth's interior
• The Earth's interior consists of the crust, mantle, outer core, and inner core
• 1. waves entering the liquid outer core


  Slow down and refract (change direction)
• 1. waves leaving the outer core


  Refract again
• Faint P-waves detected in the P-wave shadow zone led to the discovery of the solid inner core
• Scientists have measured seismic waves from thousands of earthquakes to determine the thickness of the crust, mantle, outer core, and inner core