Shield Volcano

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Shield Volcano

• Long, gently sloping structures that have central
  vents.
• Eruptions are usually not explosive.
• Kilauea and Mauna Loa are examples of shield
  volcanoes.

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Mauna Loa (Shield Volcano)
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Kilauea
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Aa Lava
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Pahoehoe

• smooth, glassy surface
• ropy texture
• covered with a skin of volcanic glass which is
  razor sharp

http//www.volcanovideo.com/Movies/PahoehoeRopy2.m
ov
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• Cinder cone
• consist almost entirely of loose, grainy cinders
  and almost no lava.
• small volcanoes, usually only about a mile across
  and up to thousand feet high.
• very steep sides and usually have a small crater
  on top.

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Paricutin
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Capulin (New Mexico)
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Sunset crater (Arizona)
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http//dsc.discovery.com/news/2007/11/09/volcano-i
ndonesia.html
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Composite (stratovolcano)

• Steep sided and symmetrical
• Alternating layers of lava and pyroclastics
• Very explosive

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Mt. Pinatubo (Phillipines 1991)
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Mt. St. Helens
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http//www.teachersdomain.org/resources/ess05/sci/
ess/earthsys/pinatubo/index.html
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http//www.teachersdomain.org/resources/ess05/sci/
ess/earthsys/lahar/index.html
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Pyroclastic Flow
fast-moving currents of hot gas, ash and rock
(collectively known as tephra)
http//www.metacafe.com/watch/119241/big_in_japan/

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mudflow composed of pyroclastic material and
water that flows down from a volcano.
Lahar
http//www.geo.mtu.edu/volcanoes/pinatubo/lahar/st
anding.wave.mpg
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Volcanic Explosivity Index or VEI.

• The scale is open-ended with the largest
  volcanoes in history given magnitude 8.
• The index logarithmic
• Every point on the scale relates to an eruption
  about ten times bigger than the one below.
• Based upon volume of product released