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The word volcano (UK: /vɒlˈkeɪnəʊ/; and US /vɔlˈkeɪnoʊ/) originates from the early 17th century, derived from the Italian vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from latin volcānus or vulcānus referring to Vulcan, the god of fire in Roman mythology.
The 1980 eruption of Mount St. Helens in Washington, which ripped apart the volcano's summit, was a Plinian eruption of Volcanic Explosivity Index (VEI) 5. [ 3 ] The strongest types of eruptions, with a VEI of 8, are so-called "Ultra-Plinian" eruptions, such as the one at Lake Toba 74 thousand years ago, which put out 2800 times the material ...
Volcanologists frequently visit volcanoes, especially active ones, to observe volcanic eruptions, collect eruptive products including tephra (such as ash or pumice), rock and lava samples. One major focus of enquiry is the prediction of eruptions; there is currently no accurate way to do this, but predicting or forecasting eruptions, like ...
Mountain Metres Feet Location and Notes Ojos del Salado: 6,893: 22,615: Argentina/Chile – highest dormant volcano on Earth: Monte Pissis: 6,793: 22,287: Argentina Nevado Tres Cruces
The volcanoes with historical eruptions include: Mount Rainier, Glacier Peak, Mount Baker, Mount Hood, Lassen Peak, and Mount Shasta. Renewed volcanic activity in the Cascade Arc, such as the 1980 eruption of Mount St. Helens, has offered a great deal of evidence about the structure of the Cascade Arc. One effect of the 1980 eruption was a ...
Volcanoes are usually mountains (sometimes islands, lakes, plateaus, calderas, seamounts or lava domes) that are formed when magma (liquid rock) wells up from inside the Earth. There are also analogous formations away from the Earth. Many volcanoes are categorized both as volcanoes and other landforms, such as mountains (if qualified).
The word is a portmanteau of the words "volcanic" and "smog". [1] The term is in common use in the Hawaiian Islands, where the Kīlauea volcano, on the Island of Hawaiʻi (the "Big Island"), erupted continuously between 1983 and 2018. [2] Based on June 2008 measurements, Kīlauea emits 2,000–4,000 tons of sulfur dioxide (SO 2) every day. [3]
Lapilli or volcanic cinders – between 2 and 64 mm (0.08 and 2.5 inches) in diameter; Volcanic bombs or volcanic blocks – larger than 64 mm (2.5 inches) in diameter; The use of tephra layers, which bear their own unique chemistry and character, as temporal marker horizons in archaeological and geological sites, is known as tephrochronology. [3]