This is my blog for my transition year environmental studies class. It is on the geography of volcanoes. I chose volcanoe because i find them very interesting, we learned a bit about them in our junior certificate cycle and i wanted to learn more.
Thursday, December 11, 2008
my introduction
source:http://www.livescience.com/environment/volcano_overview.html
This is my blog for my transition year environmental studies class. It is on the geography of volcanoes. I chose volcanoe because i find them very interesting, we learned a bit about them in our junior certificate cycle and i wanted to learn more.
This is my blog for my transition year environmental studies class. It is on the geography of volcanoes. I chose volcanoe because i find them very interesting, we learned a bit about them in our junior certificate cycle and i wanted to learn more.
Thursday, December 4, 2008
different types of volcanoes
Shield Volcanoes
shield volcanoes are ''shield'' shaped, they are basaltic lava flows and are very hot and very fluid this makes them have a very long flow. the largest shield eruption was ''Mauna Loa'' it comes 9,000m from the ocean floor and is 120km long, it is part of the island of Hawaii.
Cinder Cones
Cinder cones are formed from volcanoes that throw out small pieces of scoria and pyroclastics, these two rocks look like cinders hense the volcanoes name. these rocks build up around the vent of the volcano forming a cone shaped hill, they are pretty short eruptions and mostly only erupt once in there life time. they may form on the top of other volcanoes or on there own. Examples of a cinder cone is ''Parícutin'' in Mexico.
Stratovolcanoes
Also known as composite volcanoes these are tall cone shaped mountains they are made up of lava from lava flows, and other matter that is ejeted from the volcano, the strata (layer of material) is what gives it its name. They are known as composite volcanoes. Examples of a stratovolcano is ''Mt. Fuji'' in Japan.
super volcanoes
A super volcano is a posh term for a very large volcano, they usually have a large caldera (crater formed by a large volcanic explosion). They can do alot of damage sometimes even on a continential scale. They may even cause a huge weather change from all the sulfur and ash erupted. They are the most dangerous of volcanoes. These vocanoes are so large that they are hard to identifie centurys later. Examples of a super voncanoe is ''Lake Taupo'' in New Zealand.
submarine volcanoes
Submarine volcanoes are formed on the ocean floor, some are active and you can sometimes see them in shallow water blowing out steam and rock above the surface of the sea. Some submarine volcanoes are so deep in the sea that the weight of the water stops the volcano blowing out the steam and rocks, but they can be noticed from the discolouration of water from the ash. they form small pillars under the surface of the water because of the rapid cooling of the water on the them.
shield volcanoes are ''shield'' shaped, they are basaltic lava flows and are very hot and very fluid this makes them have a very long flow. the largest shield eruption was ''Mauna Loa'' it comes 9,000m from the ocean floor and is 120km long, it is part of the island of Hawaii.
Cinder Cones
Cinder cones are formed from volcanoes that throw out small pieces of scoria and pyroclastics, these two rocks look like cinders hense the volcanoes name. these rocks build up around the vent of the volcano forming a cone shaped hill, they are pretty short eruptions and mostly only erupt once in there life time. they may form on the top of other volcanoes or on there own. Examples of a cinder cone is ''Parícutin'' in Mexico.
Stratovolcanoes
Also known as composite volcanoes these are tall cone shaped mountains they are made up of lava from lava flows, and other matter that is ejeted from the volcano, the strata (layer of material) is what gives it its name. They are known as composite volcanoes. Examples of a stratovolcano is ''Mt. Fuji'' in Japan.
super volcanoes
A super volcano is a posh term for a very large volcano, they usually have a large caldera (crater formed by a large volcanic explosion). They can do alot of damage sometimes even on a continential scale. They may even cause a huge weather change from all the sulfur and ash erupted. They are the most dangerous of volcanoes. These vocanoes are so large that they are hard to identifie centurys later. Examples of a super voncanoe is ''Lake Taupo'' in New Zealand.
submarine volcanoes
Submarine volcanoes are formed on the ocean floor, some are active and you can sometimes see them in shallow water blowing out steam and rock above the surface of the sea. Some submarine volcanoes are so deep in the sea that the weight of the water stops the volcano blowing out the steam and rocks, but they can be noticed from the discolouration of water from the ash. they form small pillars under the surface of the water because of the rapid cooling of the water on the them.
why do volcanoes erupt?
The rock inside the earths surface melts forming magma and floats to the top of the rock as it is less dense, this makes the magma float to the surface and cause a volcanic eruption. magma contains gases and water when it hits the surface they suddenly expand into steam and gas making a massive eruption.When the magma hits the surface it is called lava and make ash clouds.
Thursday, November 20, 2008
how volcanoes work
volcanoes are made by magma under the earths surface the upper mantle to be precise (as shown in image above) boils up to the top it erupts to the surface to form magma and ash, between eruptions the magma stays in its chambers sometimes even for hundreds of years until the next eruption.
The image above shows different points of a volcanoe from inside and outside of the vent itself.
The image above shows different points of a volcanoe from inside and outside of the vent itself.
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