What IS A VOLCANO

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What IS A VOLCANO?
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A volcano is a place where lava reaches the
surface.
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There are three types of volcanoes
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Shield VolcanoA gently-sloped volcano.
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Cinder ConeA volcano made of cinders that are
blown into the air.
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CompositeA volcano built of alternating layers
of cinders and lava.
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What kind of volcano is this?
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Mount Shasta is a composite volcano.

• Over the last 10,000 years, Mt. Shasta has
  erupted on average once every 800 years. During
  the 3,500 years the volcano has erupted about
  once every 300 years. The most recent eruption
  may have occurred in 1786 A.D.

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What kind of volcano is this?
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Diamond Head is an eroded Cinder (Tuff) Cone.

• Early sailors mistakenly thought glistening
  calcite crystals inside the tuff rocks were
  diamonds, leading to the incorrect name. Diamond
  Head formed when hot magma rising up a conduit
  hit ocean water, causing large explosions that
  threw exploded magma particles (tuff) into a
  broad ring.

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What kind of volcano is this?
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Kohala is a shield volcano.

• Kohala is the oldest of the subaerial volcanoes
  that make up the Island Of Hawaii. Kohala is
  considered to be extinct because it has not
  erupted for 60,000 years.