Transcript What IS A VOLCANO?

What IS A VOLCANO?
A volcano is a place where lava
reaches the surface.
There are three types of volcanoes:
Shield Volcano:
A gently-sloped volcano
characterized by lots of lava during
eruptions and gentle slopes.
Cinder Cone:
A volcano made of cinders
that are blown into the air.
Composite:
A volcano built of alternating layers of cinders
and lava. Composite volcanoes are
characterized by steep slopes and violent
eruptions.
What kind of volcano is this?
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.
What kind of volcano is this?
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.
What kind of volcano is this?
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.