Thursday, September 25, 2008

Monday, September 22, 2008

Volcanos - What they are?

A volcano is an opening in a planet's surface or crust where molten rock, ash, and gases escape from below the surface. Volcanic activity tends to form mountains or features like mountains after multiple eruptions.

Volcanoes are found where tectonic plates are being pulled apart or are coming together. an example of this is the Mid-Atlantic Ridge where the tectonic plates are pulling apart. An example of a volcano caused by colliding plates is the Pacific Ring of Fire where volcanoes are formed from the colliding plates. Volcanoes are not usually created where two plates slide past one another. Volcanoes are also formed where there is stretching and thinning of the Earth's crust, (i.e the African Rift Valley).

Volcanoes can be created by "mantle plumes". These known as "hotspots" , for example at Hawaii, these are known to occur away from plate boundaries. Hotspot volcanoes are also found outside of earth such as in the solar system, especially on rocky planets and moons.

How to determine how destructive a volcano will be.

Without the uses of modern technology by the time you discover or heard an eruption it will probaly be too late.

Volcanoes have two main factors the decide how it will turn out. These are the silica content and dissolved gas content.

(i) The silica content determines how fast the lava will flow.

(ii) The dissolved gas content determines how volatile the eruption will be. (i.e more gas more explosive)

Thursday, September 18, 2008

This is a very interesting video showing a volcanic eruption




Here's another video showing another volcano erupting first hand!!