Transcript Volcanoes - Nova Scotia Department of Education

VOLCANOES
By Caleb Pothier and Bonita Sanford
What is A Volcano?
~An opening in the earth's crust through
which molten lava, ash, and gases are
ejected.
~A similar opening on the surface of another
planet.
~A mountain formed by the materials ejected
from a volcano.
http://dictionary.reference.com/search?q=volcano
The types Of Volcanoes
~ Shield Volcano
~ Cinder Cone Volcano
~ Composite Volcano
~ Caldera Volcano
~ Fissure Volcano
Shield volcanoes can span across hundreds of miles
and they can be huge vertically that they can reach
the clouds of earth very easy. Shield volcanoes have
a slow slope and consist of frozen lava after it is
hardened. Shield volcanoes almost always have
large craters at their summit.
http://www.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html
Cinder cone volcanoes consist of mostly loose,
grainy cinders and have very little to no lava.
Cinder cone volcanoes are normally small about a
miles span and about one thousand feet vertically.
Cinder cone volcanoes have fairly steep slopes and
normally have a small crater at the top.
http://www.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html
Composite volcanoes have another name called
“Strato Volcanoes.” Composite volcanoes consist of
lava that is mixed with sand or gravel which in turn
creates cinders or volcanic ash.
http://www.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html
Caldera volcanoes are circular depressions in the
ground over a magma chamber. Sometimes the
depression in Caldera volcanoes are covered in
with lava and volcanic ash making it hard to
recognize. This type of volcano is easier noticed
from space due to the distance and view point.
When this volcano erupts it can spew volcanic
rocks for miles and miles.
http://www.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html
Fissure volcanoes are also hard to recognize from
the ground and sometimes from space. Fissure
volcanoes have no main crater, the ground just
splits and lava pours out through the cracks. After
a fissure volcano erupts and has cooled because it’s
a solid it will look mainly like the plains.
http://www.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html
Types Of Magma
Granite magma consist of light-colored rock and is
not as heavy as basalt magma. Granite magma is
very sticky and flows rather slowly.
Basalt magma consist of dark-colored rocks and is
much heavier then granite magma. It flows more
fluidly then molten granite.
Volcano Environments
~In an island-arc environment, volcanoes lie
along the crest of an arcuate.
~In an oceanic environment, volcanoes are
aligned along the crest of a broad ridge that
marks an active fracture system in the
oceanic crust.
~In the continental environment, volcanoes
are located unstable, mountainous belts that
have thick roots of granite or granite like
rock.
Where are volcanoes likely to
occur?
Volcanoes occur in weak spots in the earth’s crust
There are many volcanoes along the Pacific Ocean.
Many islands in the Pacific Ocean are actually
volcanoes. They form a ring around the ocean
which is called the “Pacific Belt of Fire.”
Although there are some other “belts of fire”, the
“Pacific Belt of Fire” is the biggest.
There are approximately five hundred active
volcanoes, that are known, lying in these belts.
Volcanoes In Other Places
Mariner 9 imagery of
Olympus Mons volcano
on Mars
Volcanoes aren’t just a thing from earth they also
happen on other planets as seen in this picture. But
while on other planets there is no destruction as we
have seen from volcanoes on earth.
When and how do eruptions occur?
Steam and gases from magma in the earth create
bubbles that expand and burst when the pressure
above them is lessened. These bubbles usually burst
with a tremendous force that along with escaping
gas comes magma too. In some cases, it takes years
for the magma to break through the surface of the
earth.The first recorded eruption was in 781 (Fuji,
Honshu, Japan)The most recent recorded eruption was
in 2002 (Etna, Sicily, Italy)
Why do eruptions occur?
Eruptions occur when underground pressure is
released when blocks of the earth’s crust shift.
For example, earthquakes.
Damages
The most devastating destruction from volcanoes
is the tremendous loss of life. Following an
eruption in 1815, there were 56 000 people killed by
a tidal wave from a eruption. Lava from the
volcano is hot enough to catch everything in its path
on fire, even the ash from a volcano is hot enough
to start fires. Lahar can wash away houses and
uproot trees. Magma can give off poisonous gases
such as carbon monoxide. Damages from
volcanoes are very expensive to repair or replace.
Our Own Model Of An Erupting
Volcano
Movie
Of
The
Mayhem!
Works Cited
“Volcano.” The American Heritage® Dictionary of
the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company
Chris Kreger “Exploring The Environment of
Volcanoes.”
http://www.cotf.edu/ete/modules/volcanoes/vtypesv
olcan1.html
“Volcano.” Britannica Encyclopedia 2003 ed.
Works Cited Continued
Carroll, Michael. Volcanoes and Earthquakes.
Chariot Victor Publishing, March 1997
http://www.volcanoworld.org/
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