Tuesday, February 08, 2005

What is a volcano?

It is a mountain, in the middle of which there is a deep vent. At the bottom, there is a pool of molten rocks called magma. The magma mixes with gases and slowly build up the amount of pressure. The temperature rises, melting more rocks, increasing the pressure the pressure of both gases and magma.

At a certain level of pressure, the top of the vent which is partly covered by hardened lava and even plants, depending how long ago the volcano erupted, the explosion might be violent or more quiet. Then the magma is released out of the vent, flowing out of the volcano. It is now called lava.

Some volcanoes are now extinct which means that there was no volcanic activity recorded for centuries. Some volcanoes are dormant which means that they have not erupted in a long time. Other volcanoes are active but the timing between the eruptions vary greatly.

Volcano eruptions have been known to destroy forests and villages but also to have affected or even caused other natural disasters such as: mudflows, flashfloods, earthquakes, rockfalls and even tsunamis.

The pulverized rocks become ashes which can be acidic, smelly, glassy, harsh and gritty. It is said that the ashes of volcano eruptions can remain partially into the atmosphere for up to two years, affecting the weather conditions.

Comments:
THIS IS SO COOL! Very informative... I could do with some of this stuff for my assignment... is it valid? And you should add a little colour, maybe a couple of pix...it'd make it look cooler (...hotter...)
 
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