Volcano

• volcano

  • is a vent that directly connects magma to the surface of the Earth
  • describe as a mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being erupted from the earth's crust
• Summit - is the highest point of a volcano
• Crater - which is the mouth of the volcano, is sometimes confused with caldera
• Caldera - is large depression formed when a volcano erupts and collapses
• Conduit - is the pipe or the channel that conveys the magma
• Secondary pipes or the branch pipes - originate from the conduit
• Magma - come from the large underground pool of molten rocks called the magma chamber or the magma reservoir
• Active volcanoes

  • within the last 600 years have erupted
  • were recorded by man within the last 10,000 years based on the analyses of material from young volcanic deposits
  • likely to be erupt again
• Inactive volcanoes - being dormant is sometimes called a "sleeping volcano" that has not erupted for a very long time but may erupt at a future time
• Composite volcanoes or stratovolcanoes

  • are large, nearly perfect sloped structures formed by alternate solidifications of both lava and pyroclastic deposits formed from multiple eruptions
  • commonly found in pacific ring of fire
• Shield volcano - is very big in size, formed by the accumulation of lava that oozes out from the volcano
• Cinder cone volcano

  • also know as scoria cone
  • is the simplest type of volcano
  • it is formed when explosive activity throws magma into the air, which cools into cinders and settles around the volcano's opening
  • little lava, as the magma hardens and breaks into smaller pieces
  • tent to be smaller
• Phreatic or hydrothermal

  • it is a stream-driven eruption as the hot rocks come in contact with water
  • it is short-lived, characterized by ash columns but may be an onset of a more enormous eruption
• phreatomagmatic - a violent eruption due to the contact between water and magma and can be very explosive
• Strombolian

  • a periodic weak to violent eruption characterized by fountain lava
  • explosions usually occur every few minutes at regular or irregular intervals
  • burst of lava can reach hundreds of meters are caused by the bursting of large bubbles of gas, which travel upward
  • least violent explosive eruptions
• Vulcanian

  • this type of eruption results from the fragmentation and explosion of a lava plug in a volcanic conduit or from the rupture of a lava dome
  • power explosions, can travel faster than 350 meters per second (800mph) and rise several kilometers into the the air
  • may be repetitive can go on for days, months, or years
• Plinian

  • is describe as an excessively explosive and violent type of eruption
  • where gases boiling out of gas-rich magma generate massive and nearly continuous spurting blasts that core out the magma conduit and rip it apart
  • gases and volcanic fragments that can rise to 50km (35 miles) high