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Roger Weller, geology instructor

Volcano Types
by Elizabeth Light
Physical Geology
Fall 2007

Composite, Cinder Cone,& Shield Volcanoes


Composite Volcanoes


            Composite volcanoes, also known as stratovolcanoes, make up some of the most known volcanoes that we have here on earth. A composite volcano is made up of many layers of hardened lava and volcano ash from eruptions that have already taken place. That is usually why they can make such peaks because of the constant overlapping that occurs. They really make beautiful mountains and draws people close to them and that usually isnít good because when these volcanoes blow they are usually violent and have a higher number of casualties than other volcanoes.


            Like I said before, composite volcanoes are made of an overlapping of lava flows that come out when there is an explosion. All the lava that comes out during like minor explosions usually doesnít get too far, so what is left just keeps getting piled and piled on top of each other. While the lava keeps piling up this is what causes for the high steep tops of these volcanoes. Also during these eruptions cinder bombs and blocks are thrown out and so when the next eruption occurs the lava flows cement these all together also adding height to the volcano.



                                These volcanoes mostly always have  violent eruptions. The eruption is caused by the viscous magma, when it rises to the top it usually clogs up the crater pipe and gases in the crater pipe get locked up. So the pressure will increase and also the magnitude of the eruption. During these eruptions the volcanoes will throw out debris, have lots of lava flows, and they can also create landslides, avalanches and even tsunamis. The eruptions of these volcanoes cause the most damage than any of the rest. Some of the most well known volcano eruptions are from composite volcanoes like Mt. St Helens, Mt. Fuji and Mt. Etna.


Cinder Cone Volcanoes


                Cinder cones are a very classic look that a volcano can have. They have a bowl shaped crater at the top of the summit. The rock fragments, cinders are glassy and contain gas bubbles frozen into place as the magma explodes and is thrown into the air and is cooled quickly. So basically they are made up of ash and not lava. These volcanoes grow rapidly and made there maximum size fairly quickly. Cinders cones can become fairly large. Cinders are commonly found on the flanks of shield and stratovolcanoes.


                The eruptions of cinder volcanoes are usually not that harmful to the human population. There eruptions can vary from being violent to non-violent. Their eruptions do have blobs of lava thrown out  but all that usually cools very soon as it hits and air and a lot of it goes to the structure of the volcanoes, by again making it is what it is.

This is a picture of one of the most famous cinder volcanoes in Mexico.



Shield Volcanoes


                                Shield volcanoes are very large in size; the picture above shows an example of one which is the largest volcano on earth, Mauna Lau. They are formed by lava flows of low-viscosity, so over time and flow after flow, it is what makes the mountain grow. They can get so big that they have been confused with mountain ranges. Shield volcanoes are not only huge on earth but the largest mountain in our solar system Olympus Mons is a shield volcanoes. They are pretty common volcanoes.



                Shield volcanic eruptions just like any other really depends on how it will erupt, violent or non-violent. When the shields volcanoes erupt it does like the rest it sends ash in the air and lava flows out. The lava flow on these volcanoes can be very interesting because they can just flow.  They really make some pretty pictures. They usually donít have huge explosions that injure people but like all volcanoes they do damage to the environment.



                So as we can see all the different types of volcanoes are different but then again they alike  in a lot of ways but the one thing that I learned is how there are different types of volcanoes and that they are not all the same.