Plate margins- volcanoes

• Destructive plate margins

  • Plates are moving toward one another
  • Pacific Ring of Fire is made almost entirely of destructive margins
• At a destructive margin, plates are moving toward one another
• The Pacific Ring of Fire is made almost entirely of destructive margins
• Oceanic plate and continental plate collision

  • Oceanic plate is subducted by the continental plate
  • Lot of friction at this type of plate margin, so violent earthquakes are found here
• Subduction of oceanic plate

  1. Oceanic plate sinks

  2. Melts and creates new magma

  3. New magma is less dense than mantle magma, so it rises

  4. Magma forces its way through cracks in the crust and erupts to form tall and steep-sided stratovolcanoes
• Collision of two continental plates

  • Both plates crumple upwards and form tall fold mountains
  • No crust is destroyed here, so there are no volcanic eruptions
• Earthquakes occur at continental-continental collision margins
• Earthquakes all form in the same sequence