Volcanoes (3rd Quarter)

• Volcano

  • Mountain/hill that has a crater or vent where lava comes out of.
• Volcanism

  • Any activity that includes the movement of magma on the surface.
• ChamberINTERNAL PARTS OF A VOLCANO

  • Magma Chamber
  • Main Vent
  • Secondary Vent
• Magma Chamber

  • Where magma is found before it turns into LAVA
• Main Vent

  • Connects the magma chamber to the earth's surface.
• Secondary Vent

  • Random wholes in the volcano
• EXTERNAL PARTS OF A VOLCANO

  • Base
  • Slope
  • Summit
• Caldera

  • The depression of a volcano that is formed when a magma chamber collapses.
• Conduit

  • connects the chamber to the crater
  • where magma flows
• Cinder Cone Volcanoes

  • Scoria Cone
  • The simplest type of Volcano
  • Only has one single vent
• Composite Volcano

  • Stratovolcano
  • Has a cluster group of vents
  • Formed from sticky lava / pyroclastic materials.
• Shield Volcano

  • Looks similar to shields from above
  • Not accompanied by pyroclastic materials.
• Active Volcano

  • Have erupted once in the past 10,000 years
  • Shows regular activity
• Dormant/Inactive Volcano

  • No activity for the last 10,000 years
  • Magma supply is cut off
• Potentially Active Volcanoes

  • No records of volcanic activity but are young-looking.
• Phreatic / Hydrothermal

  • Steam-driven eruption in the hot rocks
  • Short-lived
  • Potentially a beginning to a violent eruption.
• Phreatomagmatic

  • Violent eruption due to the contact of magma and water
• Strombolian

  • Periodic, weak to violent eruption characterized by fountain lava.
• Vulcanian

  • Tall eruption columns that reach up to 20km high
• Plinian

  • excessively explosive type of eruption
• Magma

  • Molten rocks that lie underneath volcanoes
  • Formed at destructive plate boundaries
  • Rich is silicate (Igneous Rocks)
  • Products of crustal rocks
• Crystal content

  • Magma always contains crystals of high temperature.
• Viscosity

  • Resistance of a liquid to flow
  • Varies directly with the silica content

  Low Viscosity - Mostly basalt

  High Viscosity - Mostly Rhyolite
• Temperature

  • Affects the viscosity of magma
  • Varies Inversely

  High temperature - Low Viscosity

  Low temperature - High Viscosity
• Volatile Content

  • Promotes the magma buoyancy

  Formed by Melting of Mantle Rocks - Low Volatile Content

  Formed by Partial Melting of Crustal Rocks - High Volatile Content
• CLASSIFICATIONS OF MAGMA

  • Basaltic
  • Andesitic
  • Rhyolitic
• Volcanic Hazards

  • Ash Flow
  • Mud Flow
  • Lava Flow
  • Pyroclastic Flow
• Erosion - wearing down of landmasses by geomorphic agents.
• Geomorphology - the study of the earth’s crust.
• Diastrophism - Vertical/horizontal movement that results in mountains.
• Weathering - where rocks/other materials come in contact with the atmosphere decompose.
• Vulcanism

  • Volanicity
  • The surface discharge of magma
• Silicate - igneous rocks
• Silica - mineral abundant in the earth’s crust