Portal:Volcanoes/Intro
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A volcano is an opening (or rupture) in the Earth's surface or crust, which allows molten rock (lava), ash, and gases to escape from deep below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time. Other landforms which are often volcanic in origin include islands, craters, and crater lakes. There are four main types of volcanoes: shield volcanoes, stratovolcanoes, lava domes, and cinder cones.
Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, like 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 be caused by "mantle plumes", so-called "hotspots"; these hotspots can occur far from plate boundaries, such as the Hawaiian Islands. Volcanoes can also form where there is stretching of the Earth's crust and where the crust grows thin (called "non-hotspot intraplate volcanism"). Volcanoes are also found not only on the Earth, but also elsewhere in the Solar System on several planets and moons including Mars, Venus, and Io. (read more...)
Volcanology (also spelled "vulcanology") is the study of volcanoes, lava, magma, and related geological phenomena. The term volcanology is derived from the Latin word Vulcan, the Roman god of fire. Volcanology is a branch of geology. A volcanologist is a person who studies the formation of volcanoes, and their current and historic eruptions. (read more...)
