lesson 5

• Volcano

  •  A volcano is a vent or 'chimney' that connects molten rock (magma) from within the Earth’s crust to the Earth's surface. 
• 3 Stages of Volcanoes

  • Active
  • Dormant
  • Extinct
• Active

  • often erupts
• Dormant

  • has not erupted for 2000 years
• Extinct

  • has not erupted for at least 10,000 years
• Lava Flow

  • streams of molten rock that pour or ooze from an erupting vent.
• Types of Lava Flow

  • Andesitic Lava Flow
  • Basaltic Lava Flow
  • Rhyolitic Lava Flow
  • Sheet Lava Flow
  • Pillow Lava Flow
• Andesitic Lava Flow

  • Forms lava domes
  • Comes in small volume
• Basaltic Lava Flow

  • Fastest
  • Low Viscosity
• Rhyolitic Lava Flow

  • High Viscosity
  • Slowest
  • Associated with violent eruptions
• Sheet Lava Flow

  • Thicker surface
  • Associated with violent eruptions
• Pillow Lava Flow

  • Pillow shaped
  • Underwater lava
• Pyroclastic Flow

  Pyroclastic flow is a hot mixture of: 

  • Fresh lava
  • Gas
  • Rock
  • Pumice
  • Ash 
• Tephra Flow

  • Tephra refers to volcanic rock and lava materials that are ejected to air during an eruption.
• Types of Tephra Deposits

  1. Pele's tears
  2. Pele's Hair
  3. Pumice
  4. Scoria
• Lahar Flow

  • A mixture of fresh volcanic material and water
  • Formed by heavy rainfall or melted polar ice cap