SCIENCE 2

• Continental volcanic arc


  Mountains forged by igneous activity with production of oceanic lithosphere beneath a continent
• Continental crust


  • Thick part
  • Thicker but less dense than oceanic crust
• Oceanic crust


  • Thin part
  • Thinner but denser than continental crust
• How magma is created

  Concentration of heat in the mantle creates magma
• Magma


  Molten rock formed at depth, containing dissolved gases and crystals
• Mid-ocean ridge


  • Continuous mass of land with long width and height
  • Ocean floor
• Plate tectonic theory


  The Earth's crust is made up of plates
• Primary (P) wave


  First type of seismic wave
• Secondary (S) wave


  Second type of seismic wave
• Seismogram


  Record of seismic waves
• Seismograph


  Device that records seismic waves
• Subduction


  Slab of rocks thrusts the mantle
• Trench


  Depression in the seafloor produced by subduction
• Volcanic land arc


  • Chain of volcanoes develop parallel to the trench