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A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, ash and gases to escape from below the surface. The word volcano is derived from the name of Vulcano island off Sicily which in turn, was named after Vulcan, the Roman god of fire. Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes. Volcanoes can be caused by mantle plumes. These so-called hotspots, for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons. From Wikipedia under the
GNU Free Documentation License  atlas.geo.cornell.edu 243px x 350px | 25.70kB [source page] Click on the image above to see a 3 D movie of the Hawaiian Islands Hawaii is a chain of volcanoes that rise from the floor of the Pacific Ocean There are five volcanoes visible in this photograph The two large ones are Mauna Kea  interactive2.usgs.gov 97px x 150px | 3.90kB [source page] Top Poster Fig 14 From Yahoo Image Search: "volcanoes"  cafep11.blogspot.com Cafe P11 hu, 19 Nov 2009 00:57:01 GM Land of . Volcanoes. . Our best secret for an outstanding coffee; a land full of . volcanoes. providing minerals that fertilize the soil. Posted by Cafe P11 at 6:57 PM. Labels: guatemala, landscape ...  cosmosmagazine.com John Wed, 07 Oct 2009 23:25:59 GM Volcanoes. in this category provide some of Earth's most explosive events. They are characterised by a dome of hardened magma which covers their central vent and can blow with catastrophic force, often with scant warning. ...  stylishandtrendy.com Katie Mon, 12 Oct 2009 13:20:03 GM How can a list of top 10 beautiful . volcanoes. be made without understanding their very nature, forces which creates such gigantic fire throwing pits. Since the. From Google Blog Search: "volcanoes"  news.google.com Plumas County Newspapers The Lady Volcanoes opened with a 60-24 win over Modoc Thursday, holding the Braves scoreless through the first quarter. All 11 Chester players scored. ... news.google.com FOXNews Yellowstone rests in a caldera that is one of the world's largest volcanoes , known as a supervolcano. One feature of the system will be a new alarm system ... and more » news.google.com Examiner.com First, there is increasing volcanic activity in the Philippines from Mount Mayon, an 8000-foot volcano on the island of Luzon. The volcano is spewing ash ... From Google News Search: "volcanoes" What's similar and different about these volcanoes? Q. I have to do a homework assignment for science.What are the similarities and differences between the Cinder cone,Shield and Composite volcanoes?I've looked in my science book but it has nothing.The only things it has are how the volcanoes are made and some examples.It's really nothing if you read it though. I need to have the similarities and differences be for all 3.I like the first answer the best but I'll wait longer. Asked by Alyss Heart - Wed Nov 7 21:18:15 2007 - - 3 Answers - 0 Comments A. The differences between a cinder cone and shield---a cinder cone's angle of repose is about 30 degrees, where a shield is around 15 degrees. It's been a while but i think the magma in a cinder cone is less viscous than a shield. A composite is a little wierd. The viscosity of the magma determines how explosive a volcano will be, the less viscous the more explosive. A composite volcano can move on that scale, in one eruption it may pour magma that is like a river, then in another eruption it may explode like an a-bomb. Cinder volcanoes and composite can be explosive whereas shields are usually not. Hope this helps some. Answered by mike h - Wed Nov 7 22:05:56 2007 What type of rock makes up most island volcanoes? Q. For a science experiment I'll be building a model volcano to simulate a real one. I need to know what type of rock makes up most island volcanoes so I can make my model as accurate as possible. Asked by Nicholas M - Sun Oct 5 12:17:54 2008 - - 4 Answers - 0 Comments A. Jax got it almost right. The correct answer is basalt, but it contains more MAFIC minerals than granite, not felsic. Mafic minerals are ferromagnesian and include things like hornblende and olivine. The intrusive equivalent to basalt is gabbro, not granite! As Jax correctly indicates, basalt is more dense than most other rocks so it is commonly used for railroad ballast. You may be able to scrounge a few handfulls of basalt from your local railway tracks to make your model authentic. Answered by georock1959 - Sun Oct 5 12:53:38 2008 What do volcanoes and earthquakes tell us about plate boundaries?
Q. I know that volcanoes and earthquakes occur at plate boundaries, but what else exactly, does it tell us? I'm supposed to write an essay describing this, and I have to use 3 observations that I made from the animated gifs on this website: I don't really understand how I'm supposed to incorporate these. I would really appreciate your help! Asked by Haley - Thu Nov 5 10:31:41 2009 - - 1 Answers - 0 Comments A. The mineral composition of the melting plate. How far down the plate is subducting. In which direction the plate is moving. Answered by readupmore. - Thu Nov 5 11:34:08 2009 From Yahoo Answer Search: "volcanoes" |
