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 The word volcano is derived from the name of Vulcano island off Sicily which in turn， was named after Vulcan， the Roman god of Volcanoes are generally found where tectonic plates are diverging or 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 By contrast， volcanoes are usually not created where two tectonic plates slide past one 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 can be caused by mantle These so-called hotspots， for example at Hawaii， can occur far from plate Hotspot volcanoes are also found elsewhere in the solar system， especially on rocky planets and
