Kim's
Volcanoes
A volcano is any opening from which lava and gases are erupted. The shape of the volcano has a lot to do with how much lava is erupted and the kind of magma present. Some volcanoes are more explosive than others. The measure of how liquid a volcano may be is called viscosity. Viscosity is determined by the silica, heat, gas, and oxygen content of the lava. The more silicon present, the thicker or higher the viscosity will be.
There are two types of volcanoes. Composite volcanoes have steep slopes consisting of layers of lava and ash, and often have very explosive eruptions. This type of volcano is found along convergent boundaries and has a very high viscosity. The gas content is high, but the temperature is low. An example of a composite volcano is Mount Fuji. Shield volcanoes are broad dome shaped formations found along divergent boundaries. The viscosity is low which makes the basaltic lava runny. The silica content is low and the temperature is very high. This type of volcano erupts more passively.
Links:
Here is the really cool volcano world homepage.
Check out the active volcanoes of the world !
|
|