VOLCANOES

Stephanie Gutierrez P.2

A **volcano** is an opening, or [|rupture], in a planet's surface or [|crust], which allows hot[|magma], [|ash] and gases to escape from below the surface. The word //volcano// is derived from the name of [|Vulcano] island off [|Sicily] which in turn, was named after [|Vulcan], the[|Roman] god of fire.[|[1]] Volcanoes are generally found where [|tectonic plates] are [|diverging] or [|converging]. A[|mid-oceanic ridge], for example the [|Mid-Atlantic Ridge], has examples of volcanoes caused by [|divergent tectonic plates] pulling apart; the [|Pacific Ring of Fire] has examples of volcanoes caused by [|convergent tectonic plates] coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the [|Earth's crust] (called "non-hotspot intraplate volcanism"), such as in the [|African Rift Valley], the[|Wells Gray-Clearwater volcanic field] and the [|Rio Grande Rift] in North America and the European [|Rhine Graben] with its [|Eifel] volcanoes. Volcanoes can be caused by [|mantle plumes]. These so-called [|hotspots], for example at[|Hawaii], can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the [|solar system], especially on rocky planets and moons.  [|Lakagigar] fissure vent in [|Iceland], source of the major world climate alteration of 1783-84. [|Skjaldbreiður], a shield volcano whose name means "broad shield" January 2009 image of the rhyolitic lava dome of [|Chaitén Volcano], southern [|Chile]during its 2008-2009 eruption. 