Physical Geography 110
November 29, 2011
2. What is a Volcano?
A Volcano is a mountain or hill, typically conical, having
a crater or vent through which lava, rock fragments, hot
vapor, and gas are or have been erupted from the
The basic parts that make a volcano are the magma
chamber, conduit, branch pipes,throat, summit, vent,
and layers of lava and ash emitted by the volcano.
4. Volcanic Features
The features of a volcano depend on various factors.
Such as the way lava comes out of it and the way it
erupts. Some volcanoes have rugged peaks and others
have summit craters. Some different types of volcanic
formations are shield volcanoes, lava domes, and
cryptodomes. Shield volcanoes are formed when lava
is slowly pushed out. Lava domes are formed when
their is a violent eruptions. Cryptodomes are formed
when a violent eruptions occurs and a bulge is forced.
6. Volcanic Eruption
Magma collects under the earths surface in
magma chambers. Since the liquid magma is
less dense than the rock the pressure pushes
the magma to erupt through the surface.
Volcanic eruptions can also occur when the
Earth’s plate collide with each other and push
the magma towards the Earth’s surface through
ﬁssures and volcanic vents.
8. Magma & Lava
Magma is a mixture of
molten rock and other
solids found beneath the
Earth’s surface and inside
the volcano. Its
temperature ranges from
700 to 1300 degrees
celsius. Lava is the name
given to magma when it is
already erupted and on the
9. Classifications of
Active- Active volcanoes are those that erupt frequently.
Scientist consider a volcano to be erupting if it shows
signs of gas emission or earthquake activity.
Extinct- Extinct volcanoes are volcanoes that are very
unlikely to erupt because they no longer have a magma
Dormant- Dormant Volcanoes are ones that have
erupted in historical records, but do not have recent
10. The Affect of Volcanoes
Research shows that 1 in 10 people in the world are
considered to live in a “danger zone” of an active
Poisonous gases released from volcanic eruptions
cause illness and death to people.
There has been an estimated 200,00 people to die
because of volcanic eruptions during the last 500
11. Largest Eruption
The deadliest and largest
volcanic eruption was in
1815. It was the Tambora
volcano in Indonesia. It
caused over 92,000
The eruption caused many
changes in temperature
and atmosphere including
what was considered “the
year without summer”.
12. Volcanoes in California
Their 11 are volcanoes
is total in California but
only 5 are active.
They are Medicine
Lake, Mount Shasta,
Lassen Peak, Clear
Lake, and Long Valley
14. Massive Volcanoes
Yellowstone is the largest Mauna Lua is the largest
super volcano and is located volcano in the world and is
in Wyoming. located in Hawaii.