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Volcanoes Of The French Southern And Antarctic Lands
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that 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, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanism
Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a vent. It includes all phenomena resulting from and causing magma within the crust or mantle of the body, to rise through the crust and form volcanic rocks on the surface. Magmas, that reach the surface and solidify, form extrusive landforms. Volcanic processes Magma from the mantle or lower crust rises through the crust towards the surface. If magma reaches the surface, its behavior depends on the viscosity of the molten constituent rock. Viscous (thick) magma produces volcanoes characterised by explosive eruptions, while non-viscous (runny) magma produce volcanoes characterised by effusive eruptions pouring large amounts of lava onto the surface. In some cases, rising magma can cool and solidify without reaching the surface. Inste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanology
Volcanology (also spelled vulcanology) is the study of volcanoes, lava, magma and related geological, geophysical and geochemical phenomena (volcanism). The term ''volcanology'' is derived from the Latin word ''vulcan''. Vulcan was the ancient Roman god of fire. A volcanologist is a geologist who studies the eruptive activity and formation of volcanoes and their current and historic eruptions. 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 eruptions, like predicting earthquakes, could save many lives. Modern volcanology image:Icelandic tephra.JPG, Volcanologist examining tephra horizons in south-central Iceland. In 1841, the first volcanological observatory, the Vesuvius Observatory, was founded in the Kingdom o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roman Mythology
Roman mythology is the body of myths of ancient Rome as represented in the literature and visual arts of the Romans. One of a wide variety of genres of Roman folklore, ''Roman mythology'' may also refer to the modern study of these representations, and to the subject matter as represented in the literature and art of other cultures in any period. Roman mythology draws from the mythology of the Italic peoples and ultimately from Proto-Indo-European mythology. Roman mythology also draws directly on Greek mythology, potentially as early as Rome's protohistory, but primarily during the Hellenistic period of Greek influence and through the Roman conquest of Greece, via the artistic imitation of Greek literary models by Roman authors. The Romans identified their own gods with those of the ancient Greeks—who were closely historically related in some cases, such as Zeus and Jupiter—and reinterpreted myths about Greek deities under the names of their Roman counterparts. Greek and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulcan (mythology)
Vulcan ( la, Vulcanus, in archaically retained spelling also ''Volcanus'', both pronounced ) is the god of fire including the fire of volcanoes, deserts, metalworking and the forge in ancient Roman religion and myth. He is often depicted with a blacksmith's hammer. The Vulcanalia was the annual festival held August 23 in his honor. His Greek counterpart is Hephaestus, the god of fire and smithery. In Etruscan religion, he is identified with Sethlans. Vulcan belongs to the most ancient stage of Roman religion: Varro, the ancient Roman scholar and writer, citing the Annales Maximi, records that king Titus Tatius dedicated altars to a series of deities including Vulcan. Etymology The origin of the name is unclear. Roman tradition maintained that it was related to Latin words connected to lightning (), which in turn was thought of as related to flames. This interpretation is supported by Walter William Skeat in his etymological dictionary as meaning ''lustre''. It has be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeolian Islands
The Aeolian Islands ( ; it, Isole Eolie ; scn, Ìsuli Eoli), sometimes referred to as the Lipari Islands or Lipari group ( , ) after their largest island, are a volcanic archipelago in the Tyrrhenian Sea north of Sicily, said to be named after Aeolus, the mythical ruler of the winds. The islands' inhabitants are known as Aeolians ( it, Eoliani, links=no). The islands had a permanent population of 14,224 at the 2011 census; the latest official estimate is 15,419 as of 1 January 2019. The Aeolian Islands are a popular tourist destination in the summer and attract up to 600,000 visitors annually. There are seven significant islands: Lipari, Vulcano, Salina, Stromboli, Filicudi, Alicudi and Panarea, and a set of minor islands and rocks. Geography The ''Lipari Islands'' are 30 km and 80 km off the north coast of Sicily in the Tyrrhenian Sea. Vulcano is located closest to the Sicilian coast. Lipari and Salina follow to the north, Filicudi and Alicudi to the west, and Pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulcano
Vulcano ( scn, Vurcanu) or Vulcan is a small volcanic island belonging to Italy in the Tyrrhenian Sea, about north of Sicily and located at the southernmost end of the seven Aeolian Islands. The island is known for its volcanic activity and contains several volcanic calderas, including one of the four active volcanoes in Italy that are not submarine. The English word "volcano", and its equivalent in several European languages, derives from the name of this island, which derives from the Roman belief that the tiny island was the chimney of Vulcan, the Roman god of fire. In November 2021, 150 people were evacuated from the island's harbour area due to increased volcanic activity and gases; an amber alert had been issued in October 2021 after several significant changes in the volcano's parameters. Geography Vulcano is located approximately north of Sicily and is approximately long by wide. The island is in area and rises to above sea level. The island is separated by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic
Pyroclastic rocks (derived from the el, πῦρ, links=no, meaning fire; and , meaning broken) are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroclasts. Pyroclastic rocks are a type of volcaniclastic deposit, which are deposits made predominantly of volcanic particles. 'Phreatic' pyroclastic deposits are a variety of pyroclastic rock that forms from volcanic steam explosions and they are entirely made of accidental clasts. 'Phreatomagmatic' pyroclastic deposits are formed from explosive interaction of magma with groundwater. Unconsolidated accumulations of pyroclasts are described as tephra. Tephra may become lithified to a pyroclastic rock by cementation or chemical reactions as the result of the passage of hot gases (fumarolic alteration) or groundwater (e.g. hydrothermal alteration and diagenesis) and burial, or, if it is emplaced at temperatures so hot that the soft glassy pyroc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Winter
A volcanic winter is a reduction in global temperatures caused by volcanic ash and droplets of sulfuric acid and water obscuring the Sun and raising Earth's albedo (increasing the reflection of solar radiation) after a large, particularly explosive volcanic eruption. Long-term cooling effects are primarily dependent upon injection of sulfur gases into the stratosphere where they undergo a series of reactions to create sulfuric acid which can nucleate and form aerosols. Volcanic stratospheric aerosols cool the surface by reflecting solar radiation and warm the stratosphere by absorbing terrestrial radiation. The variations in atmospheric warming and cooling result in changes in tropospheric and stratospheric circulation. Historic examples The effects of volcanic eruptions on recent winters are modest in scale, but historically have been significant. Toba supereruption A proposed volcanic winter occurred around 71,000–73,000 years ago following the supereruption of Lake Toba on S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troposphere
The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From the planetary surface of the Earth, the average height of the troposphere is in the tropics; in the middle latitudes; and in the high latitudes of the polar regions in winter; thus the average height of the troposphere is . The term ''troposphere'' derives from the Greek words ''tropos'' (rotating) and '' sphaira'' (sphere) indicating that rotational turbulence mixes the layers of air and so determines the structure and the phenomena of the troposphere. The rotational friction of the troposphere against the planetary surface affects the flow of the air, and so forms the planetary boundary layer (PBL) that varies in height from hundreds of meters up to . The measures of the PBL vary according to the latitude, the landform, and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula . It is a colorless, odorless and viscous liquid that is miscible with water. Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid, but to the contrary dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus the reverse procedure of adding water to the acid should not be performed since the heat released may boi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaiian Hotspot
The Hawaii hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean. One of the best known and intensively studied hotspots in the world, the Hawaii plume is responsible for the creation of the Hawaiian–Emperor seamount chain, a mostly undersea volcanic mountain range. Four of these volcanoes are active, two are dormant; more than 123 are extinct, most now preserved as atolls or seamounts. The chain extends from south of the island of Hawaii to the edge of the Aleutian Trench, near the eastern coast of Russia. While most volcanoes are created by geological activity at tectonic plate boundaries, the Hawaii hotspot is located far from plate boundaries. The classic hotspot theory, first proposed in 1963 by John Tuzo Wilson, proposes that a single, fixed mantle plume builds volcanoes that then, cut off from their source by the movement of the Pacific Plate, become increasingly inactive and eventually erode below sea level ove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
