Monday, October 24, 2011

Volcanoes

Hello today i'm going to talk about volcanoes. Volcanoes are formed by when two tectonic plates push against each other and magma pours out. Than the lava cools down and it would keep on creating layers which would eventually get higher and higher.      



Hot Spots are volcanoes that are not connected  with plate boundaries. Hot Spots form deep under Earths mantle. They come up from the ocean and starts getting taller and taller until it comes up to the surface. Later on tectonic plates moves over a hot spot and it gets pushed away. So the ones that are furthest away from a hot spot the older it is. The volcano that is directly above a hot spot is the youngest. 
Volcanoes erupt by the magma chamber filled up with too much magma and eventually it would explode. There are two different type of eruptions. First there is silent eruptions. Second there are violent eruptions. All types of magma and lava can flow because they have viscosity which is a liquid resistance to flow.  


   SILENT BUT DEADLY
  VIOLENT VOLCANO

Shield volcanoes are usually found among the tectonic plates or the oceanic hot spots. They are large volcanoes that has a smooth like surface and they are shaped as a shield. Shield volcanoes are formed by basaltic lava. An Composite volcano is a large and tall volcano which are formed by andesitic and rhyolitic lava and volcanic ash. Cinder Cone volcanoes are small and steep-sided volcanoes which almost looks like an Composite volcano. They are formed by gas-rich, basaltic lava.  
 
  
  
  
                                 volcanic ash


And that was my blog on volcanoes!!!!!!!!