Friday, March 18, 2011

Volcanoes

Volcano eruptions are also a cause for earthquakes which result in tsunamis. We will now learn more about Volcanoes.

Here is an informative video: Volcanoes

Basically, volcanoes are formed by the movement of tectonic plates on the surface of the earth. These plates are basically huge pieces of rock that ‘float’ on the mantle (a layer of the earth that is sort-of liquid rock). The tectonic plates are in constant motion, albeit very slow motion. They sometimes move toward each other, other times they’ll move apart, and still other times one will sink while the other rises above it.

When a eruption is about to happen, hot material from below rises and leaks into the crust. Magma, comes either from a melt of subducted crustal material, and which is light and buoyant after melting, or it may come from deeper in the interior of a planet and is light and buoyant because it is very hot.

Magma, rising from lower reaches, gathers in a pool, in a weak portion of the overlying rock called the magma chamber. Eventually, but not always, the magma erupts onto the surface. Strong earthquakes accompany rising magma, and the volcanic cone may swell in appearance, just before an eruption, as illustrated in this picture. White arrows in the picture show the volcano getting bigger as magma rises inside. Scientist often monitor the changing shape of a volcano, especially prior to an eruption. If the volcanoes do not erupt at the top, which means that it erupts from its side, and if the volcanoe is near a sea, the sliding debris that fall into the sea is likely to cause a Tsunami. Underwater eruptions also happen and as i have posted earlier, It will result in Tsunamis and cause much damage

No comments:

Post a Comment