Search This Blog

Saturday, February 12, 2011

Volcanoes 101 [Video]

A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface. The word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn originates from Vulcan, the name of a god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology.

Volcanoes are generally found where tectonic plates are diverging or converging. Presently there are about 500 active volcanoes in the world – the majority following along the Pacific 'Ring of Fire' – and around 50 of these erupt each year. The United States is home to 50 active volcanoes. There are more than 1,500 potentially active volcanoes. An estimated 500 million people live near active volcanoes.