Volcanoes · 2014-12-07 · Volcanoes By: Brianna Petrilla A topic that we have discussed in our class that really interests me is volcanoes. Volcanoes are an amazing phenomenon.
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Volcanoes
By: Brianna Petrilla
A topic that we have discussed in our class that really interests me is
volcanoes. Volcanoes are an amazing phenomenon. They are one of the most
fascinating natural occurrences on planet earth, in my opinion. They are all over
the world, some are even here in Utah. Not only are they on land, they are even
under the deep ocean waters as well. “There are about 550 active volcanos in the
world. On Average, about 15 of them will erupt this week, 55 this year, and
perhaps 160 this decade” (Darrel Hess, 2014, p.418). They are as beautiful as they
are dangerous though. Volcanoes can be extremely deadly and destructive.
Volcanoes affect our lives dramatically. Volcanoes can kill mass numbers of
people who live near them. Communities build up around many volcanoes, this is
dangerous. You may think the volcano you built your house near won’t erupt in
your lifetime, well there’s always a chance it could erupt. Avoid the danger by not
building your home near volcanoes. “A volcano is considered active if it has
erupted at least once within historical history and is considered likely to do so
again” (Darrel Hess, 2014, p.418). Throughout history there have been many tragic
events involving volcanic eruptions. Some examples of how extremely dangerous
volcanoes can be are; Tambora located in Indonesia killing 92,000 in 1815, Mount
Pelee located in Martinique killing 29,025 in 1902, Ruiz located in Columbia
killing 25,000 in 1985, (infoplease, 2007) and so many more devastating volcanic
disasters.
http://volcanoes.usgs.gov/Imgs/Jpg/Ruiz/30410135_071_caption.html
The
aftermath of
the eruption
of Ruiz,
located in
Columbia in
1985.
Lahars Flow (Volcanic mud
flow consisting of ash and
pyroclastic deposits)
“Most volcanoes that form on large bodies of land occur where two tectonic
plates come together, and one of them is forced to subduct below the other one into
the hot mantle.” (Schmidlkofer) The pressure and heat increases causing the rock
to turn into magma. This magma in the subduction zone gets pushed to the surface,
which causes volcanoes to form.
There are four main types of volcanoes; Shield Volcanoes, Stratovolcanoes
(or Composite), Lava Domes, and Pyroclastic Cones (or Cinder Cones). These
different types of volcanos are all very unique looking and come in various
different shapes and sizes.
Shield Volcanoes are very interesting. “Their name derives from their low-
angle profile, which resembles the personal shields carried by warriors.”
(Smithsonian Institution) “Some shield volcanos are massive and very high, but
http://www.angelfire.com/sc3/popocatepetl/page2.html
This is how a volcano is
created.
they are never steep sided” (Darrel Hess, 2014, p.422). They are formed by the
constant buildup of lava flow. The lava flow comes from the fissure vent system.
Shield Volcanoes can dramatically vary in size. Some Shield Volcanos around the
world include; Mauna Loa (Hawaii), Mauna Kea (Hawaii), Darwin (Galápagos
Islands), Fernandina (Galápagos Islands), Alcedo (Galápagos Islands), Belknap
(Oregon), Newberry (Oregon), Medicine Lake (California), and the list goes on
and on.
That’s the Shield Volcano, Mauna
Loa, located in Hawaii. Fissure Vent
http://commons.wikimedia.org/wiki/File:Mauna_Kea_from_Mauna_Loa_Observatory,_Hawaii_-_20100913.jpg
https://www.flickr.com/photos/djdude101e/7355007102/
http://www.geographic.org/photos/volcanoes/volca
no_photos_24.html
This is the Shield
Volcano,
Fernandina,
located in the
Galápagos Islands.
Volcanic Rock
“Basalt”
Consists of
Layers of
Solidified Lava
Flows
Stratovolcanoes (or Composite) are what most people picture when they hear
the word volcanoes. They look like towering, somewhat triangular peaks. Stratovolcanoes are made of stratified layers of thick, sticky, lava flows and
fragmental material. “These mountains build up steep sides by having layers of
ejected pyroclastics (ash and cinders) from explosive eruptions alternate with lava
flows from nonexplosive eruptions” (Darrel Hess, 2014, p.423). Stratovolcanoes
are formed from multiple eruptions from flank and summit vents. Compound
stratovolcanoes are able to form when the focus of the eruption moves, which
causes more than one volcano to form. Some examples of Stratovolcanoes are;
Santa Maria (Guatemala), Mount Jefferson (Oregon), Mount Baker (Washington),
Kamen (Russia), Mombacho (Nicaragua), and there are many more.
http://www.fitpacking.com/2009/NCNP.cfm
The
Stratovolcano,
Mount Baker,
located on
Northern
Cascades in
Washington.
Stratovolcanoes are steep-sided
symmetrical cones
--------------------------------
-
Lava Domes are created when thick, sticky magma is pushed out of the vent
and builds up around it. Lava domes have very steep edges. They can form during
single eruption, or even from occasional lava extrusion. Some Lava Domes are;
Soufrière Hills (Montserrat), Soufrière St. Vincent (Windward), El Chichón
(Mexico), Ceboruco (Mexico), Mount Unzen (Japan), and there a lot more.
http://demiseofcomplexsocieties.blogspot.com/2
011/12/explosive-eruption.html
This is the Lava Dome volcano,
El Chichón, located in Francisco
León, north-western Chiapas,
Mexico.
https://readtiger.com/wkp/en/Mount_Jefferson_(Oregon)
This is the
Stratovolcano,
Mount
Jefferson,
located in the
Cascade Range
of Oregon.
Eruption Cloud
Fissures Eruption Column
Crater
Steep slopes of
solidified and
pyroclastics.
Pyroclastic Cones (or Cinder Cones) are one of the most plentiful forms of
volcanoes. They have a cone like appearance which is probably why they are also
called Cinder Cones. Pyroclastic Cones name is made of the Greek word pyro
(which means fire) and klastos (which means broken). (Smithsonian Institution)
The name makes sense since these volcanoes are made of fragmental material.
They are formed from a single volcanic explosion, where the materials released
during the explosion build up around the vent. Some Pyroclastic Cones are;
Bárcena (Mexico), Crater Lake (Oregon), Cerro Negro (Nicaragua), San Quintin
Volcanic Field (Mexico), and many, many more.
http://www.japan-guide.com/e/e4452.html
This is the Lava Dome volcano,
Mount Unzen, located on the
island of Kyūshū, Japan
4,9
00
fe
et
http://oregon365minblog.blogspot.co
m/2011/04/oregons-volcanoes.html
The Pyroclastic Cone volcano,
Crater Lake, located in southern
Oregon.
http://www.summitpost.org/cerro-negro/785143
The Pyroclastic Cone
volcano, Cerro Negro,
located in the Cordillera
de los Maribios
mountain range in
Nicaragua.
Cone
Crater
Composed of ash/pyroclastic cinder-size pieces
Works Cited
http://volcanoes.usgs.gov/Imgs/Jpg/Ruiz/30410135_071_c
aption.html
http://www.angelfire.com/sc3/popocatepetl/page2.html
http://commons.wikimedia.org/wiki/File:Mauna_Kea_fro
m_Mauna_Loa_Observatory,_Hawaii_-_20100913.jpg
https://www.flickr.com/photos/djdude101e/7355007102/
http://www.geographic.org/photos/volcanoes/volcano_pho
tos_24.html
http://www.fitpacking.com/2009/NCNP.cfm
https://readtiger.com/wkp/en/Mount_Jefferson_(Oregon)
http://demiseofcomplexsocieties.blogspot.com/2011/12/exp
losive-eruption.html
http://www.japan-guide.com/e/e4452.html
http://oregon365minblog.blogspot.com/2011/04/oregons-
volcanoes.html
http://www.summitpost.org/cerro-negro/785143
http://www.infoplease.com/ipa/A0197833.html
The Internal Processes . (2014). In D. Hess, McKnight's
Physical Geography: A Landscape Appreciation Eleventh
Edition (pp. 400-431). Upper Saddle River: Pearson.
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