Volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth. It allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging. Hotspots are volcanic areas thought to be formed by mantle plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary.
About Volcano in brief
A volcano is a rupture in the crust of a planetary-mass object, such as Earth. It allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging. Most divergent plate boundaries are at the bottom of the oceans, and so most volcanic activity on the Earth is submarine. Hotspots are volcanic areas thought to be formed by mantle plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary. Large eruptions can affect atmospheric temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth’s troposphere. Historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines. The word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology. The most common perception of a volcano is that it is a conical mountain, spewing poisonous gases at its summit. Examples include the East African Rift and the Yellowstone Caldera of the North American plate. However, the mantle plume hypothesis has been questioned. Sustained upwelling plumes of hot mantle rock develop under the interior of a continent and lead to rifting. Early stages of rifting are characterized by flood basalts and may progress to a point where the tectonics of the continent is completely split.
A divergent plate boundary then develops between the two halves of the split plate, often called a rifting rifting point, and often fails to completely split the continental lithosphere and split the plate completely. This can lead to the formation of new volcanoes called volcanic arcs. Typical examples are the volcanoes in the Pacific Ring of Fire,such as the Cascade Volcanoes or the Japanese Archipelago, or the Sunda Arc of Indonesia. The Hawaiian Islands are thought to have been formed in such a manner, as has the Snake River Plain, with Yellowstone Calder being the part currently above the Yellowstone hotspot, However, this can be questioned as the mantle plume has been questioned by upwelled diapirs from the core–mantle boundary, 3,000 kilometers deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Most volcanoes on Earth are found underwater, and most are found in subduction zones where two plates, usually an oceanic plate and a continental plate, collide. In a process called flux melting, water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, thus creating magma. This magma tends to be extremely viscous because of its high silica content, so it often does not reach the surface but cools and solidifies at depth.
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This page is based on the article Volcano published in Wikipedia (as of Dec. 27, 2020) and was automatically summarized using artificial intelligence.
