Tuesday, September 16, 2008

Before They Erupt



Scientists can usually tell if a volcano is about to erupt:

-As the magma moves nearer the surface, it releases gases. These gases have quite a bad odour and the smell lingers in the air surrounding the volcano. One of the gases released would be sulfur dioxide; an increase in the level of sulfur dioxide in the air can be detected by a correlation spectrometer.

-There can also be small earthquakes/vibrations caused by the movement of magma. These can be detected by a seismograph.

-The sides of a volcano can also swell/bulge outwards due to magma gathering in the magma chamber. These can be measured by geodimeters.

Image Source: www.astronet.ru



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