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Volcanoes Where they Exist and how they are have Formed

Uploaded by jimih4evr on Oct 31, 2011

This paper will discuss volcanoes, where they exist, how they are formed, and how eruptions are caused.
Introduction:
For the people who live near them, volcanoes occupy a large part of the history and mythology. The ancient Romans told of Vulcan, the god of fire and metals who kept his blacksmith shop beneath certain mountains. The Hawaiians believed that Pele, the hot-tempered goddess, was responsible for the formation of their islands. When Pele argued with her sister, her foot-stamping would cause earthquakes, then she would use her magic stick to dig out the craters from which the lava flowed (Mayberry 1997).
However, science was slow to catch up to the importance of volcanism in the evolution of the Earth. In the 18th century, there was a major school of thought that held that molten rocks and volcanoes were merely accidents caused by burning coal seams.
Geologists today realize that the process involved in the creation of a volcano is complex and profound, resulting from the thermal evolution of planetary bodies and plate tectonics. It is difficult for heat to escape from large bodies by conduction or radiation. Instead, partial meltdowns and the buoyant rise of magma are major contributors to the process of heat flux from inside the Earth. Volcanoes are the surface manifestation of this thermal process, which starts deep inside the Earth, and which hurls its results in the form of ash and fire, high into the atmosphere (Decker and Decker 1981).
What is a Volcano?
The term volcano can refer either to the landform created by the solidified lava and fragmented volcanic debris that build up near the vent, or to the vent itself, from which the magma erupts to the surface. For example, one could refer to the large lava flows that erupted from the Kilauea Volcano in Hawaii, with the word volcano meaning a vent. However, one could also say that Kilauea is a gently sloping volcano of modest size as volcanoes go, and in this case the reference would be to the landform.
By a broad definition, all igneous rocks come from volcanoes. If igneous rocks harden from magma that has not gotten to the surface, they are referred to as intrusive igneous rocks, and this process is called plutonism. Igneous rocks that cool and harden at the Earth’s surface are called extrusive igneous rocks, and are unequivocally products of volcanism.
Types of Volcanoes:
Volcanoes can be...

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Uploaded by:   jimih4evr

Date:   10/31/2011

Category:   Science

Length:   5 pages (1,105 words)

Views:   1697

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