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Öræfajökull Belt
Öræfajökull (; ' Öræfi glacier' or 'wasteland glacier') is an ice-covered volcano in south-east Iceland. The largest active volcano and the highest peak in Iceland at , it lies within the Vatnajökull National Park and is covered by part of the glacier. The original Norse settlers named the volcano Knappafellsjǫkull (Old Norse: ; Modern Icelandic: Hnappafellsjökull ; 'knobs mountain glacier'). The current name, ''Öræfajökull'', was eventually adopted after the 1362 eruption. Description Öræfajökull is located at the southern extremity of the Vatnajökull glacier and overlooking the Ring Road between Höfn and Vík. It is the largest active volcano in the country, and on the summit crater's northwestern rim is Hvannadalshnúkur, the highest peak in Iceland at . Geographically, Öræfajökull is considered part of Vatnajökull, and the area covered by glacier is within the boundary of Vatnajökull National Park. Activity Öræfajökull has erupted twice in his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tephra
Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they remain as tephra unless hot enough to fuse into pyroclastic rock or tuff. Tephrochronology is a geochronological technique that uses discrete layers of tephra—volcanic ash from a single eruption—to create a chronological framework in which paleoenvironmental or archaeological records can be placed. When a volcano explodes, it releases a variety of tephra including ash, cinders, and blocks. These layers settle on the land and, over time, sedimentation occurs incorporating these tephra layers into the geologic record. Often, when a volcano explodes, biological organisms are killed and their remains are buried within the tephra layer. These fossils are later dated by scientists to determine the age of the fossil and its place within the geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iceland Plume
The Iceland hotspot is a hotspot (geology), hotspot which is partly responsible for the high volcanic activity which has formed the Iceland Plateau and the island of Iceland. Iceland is one of the most active volcano, volcanic regions in the world, with eruptions occurring on average roughly every three years (in the 20th century there were 39 volcanic eruptions on and around Iceland). About a third of the basaltic lavas erupted in recorded history have been produced by Icelandic eruptions. Notable eruptions have included that of Eldgjá, a fissure of Katla volcano, Katla, in 934 (the world's largest basaltic eruption ever witnessed), Laki in 1783 (the world's second largest), and several eruptions beneath ice caps, which have generated devastating Jökulhlaup, glacial bursts, most recently in 2010 after the eruption of Eyjafjallajökull. Iceland's location astride the Mid-Atlantic Ridge, where the Eurasian Plate, Eurasian and North American Plates are moving apart, is partl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciers Of Iceland
The glaciers and ice caps of Iceland cover 11% of the land area of the country (about 11,400 km² out of the total area of 103,125 km²) and have a considerable impact on its landscape and meteorology. Glaciers are also contributing to the Icelandic economy, with tourists flocking to the country to see glaciers on snowmobiles and on glacier hiking tours. However, the recent loss of ice due to climate change is an increasing concern in Icelandic society. Description An ice cap is a mass of glacial ice that covers less than 50,000 km² of land area covering a highland area and they feed outlet glaciers. Many Icelandic ice caps and glaciers lie above volcanoes, such as Grímsvötn and Bárðarbunga, which lie under the largest ice cap, Vatnajökull. The caldera of Grímsvötn is 100 km² in area, and Bárðarbunga is 60 km². When volcanic activity occurs under the glacier, the resulting meltwater can lead to a sudden glacial lake outburst flood, known in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography Of Iceland
Iceland ( ) is an island country at the confluence of the North Atlantic and Arctic oceans, east of Greenland and immediately south of the Arctic Circle, atop the constructive boundary of the northern Mid-Atlantic Ridge about from Scotland and from New York City. One of the world's most sparsely populated countries, Iceland's boundaries are almost the same as the main island – the world's 18th largest in area and possessing almost all of the country's area and population and also it is world's 9th largest island country. It is the westernmost European country and has more land covered by glaciers than in all of continental Europe. The total size is . It has an exclusive economic zone of . Statistics Iceland is an island country in Northern Europe, straddling the Eurasian and North American plates between the Greenland Sea and the North Atlantic Ocean, northwest of the British Isles. Extent (locations outside mainland in parentheses) :North: Rifstangi, 66°32′3" N ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Cauldron
Ice cauldrons are ice formations within glaciers that cover some subglacial volcanoes. They can have circular to oblong forms. Their surface areas reach from some meters (as indentations or holes in the ice) to up to 1 or more kilometers (as bowl shaped depressions). Their existence is connected to ice-volcano interaction in two possible ways: They can be formed in the course of a subglacial eruption or on top of a continuously active subglacial high temperature geothermal area. In both cases, a jökulhlaup may be produced in connection with them. Formation and continued existence of ice cauldrons Ice cauldrons and subglacial eruptions When an eruption takes place under a bigger glacier, e.g. an ice cap, it normally begins with an effusive stage. The heat forms an ice cave and pillow lava is produced. After some time, the eruption has reached a stage where the pressure drops within the ice vault and the eruption style changes to become explosive. Hyaloclastite is produced and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano Warning Schemes Of The United States
In October 2006, the United States Geological Survey (USGS) adopted a nationwide alert system for characterizing the level of unrest and eruptive activity at volcanoes. The system is now used by the Alaska Volcano Observatory, the California Volcano Observatory (California and Nevada), the Cascades Volcano Observatory (Washington, Oregon and Idaho), the Hawaiian Volcano Observatory and the Yellowstone Volcano Observatory (Montana, Wyoming, Colorado, Utah, New Mexico and Arizona). Under this system, the USGS ranks the level of activity at a U.S. volcano using the terms "normal", for typical volcanic activity in a non-eruptive phase; "advisory", for elevated unrest; "watch", for escalating unrest or an eruption underway that poses limited hazards; and, "warning", if a highly hazardous eruption is underway or imminent. These levels reflect conditions at a volcano and the expected or ongoing hazardous volcanic phenomena. When an alert level is assigned by an observatory, accompanying tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icelandic Meteorological Office
Icelandic Meteorological Office (IMO; is, Veðurstofa Íslands) is Iceland's national weather service and as such a government agency under the Ministry of Environment and Natural Resources. It is also active in volcano monitoring, esp. volcano seismology, and, together with other institutions, responsible for civil protection in IcelandMission. About the Icelandic Meteorological Office. (28.5.2010) Retrieved 18 August 2020. Aims and functions "The research focus of IMO is on and ,[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icelandic Language
Icelandic (; is, íslenska, link=no ) is a North Germanic language spoken by about 314,000 people, the vast majority of whom live in Iceland, where it is the national language. Due to being a West Scandinavian language, it is most closely related to Faroese, western Norwegian dialects, and the extinct language, Norn. The language is more conservative than most other Germanic languages. While most of them have greatly reduced levels of inflection (particularly noun declension), Icelandic retains a four- case synthetic grammar (comparable to German, though considerably more conservative and synthetic) and is distinguished by a wide assortment of irregular declensions. Icelandic vocabulary is also deeply conservative, with the country's language regulator maintaining an active policy of coining terms based on older Icelandic words rather than directly taking in loanwords from other languages. Since the written language has not changed much, Icelandic speakers can read classic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean world, the Roman Empire (Western Roman Empire and Eastern Roman Empire), and medieval "Christendom" (Western Christianity and Eastern Christianity). Beginning with the Renaissance and the Age of Discovery, roughly from the 15th century, the concept of ''Europe'' as "the West" slowly became distinguished from and eventually replaced the dominant use of "Christendom" as the preferred endonym within the region. By the Age of Enlightenment and the Industrial Revolution, the concepts of "Eastern Europe" and "Western Europe" were more regularly used. Historical divisions Classical antiquity and medieval origins Prior to the Roman conquest, a large part of Western Europe had adopted the newly developed La Tène culture. As the Roman domain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pumice Raft
A pumice raft is a floating raft of pumice created by some eruptions of submarine volcanoes or coastal subaerial volcanoes. Biologists suggest that animals and plants have migrated from island to island on pumice rafts. Pumice rafts have unique characteristics such as the highest surface-area-to-volume ratio known for any rock type, long term flotation and beaching in the tidal zone, exposure to a variety of conditions, including dehydration, and an ability to absorb many potentially advantageous elements/compounds. For at least these reasons, astrobiologists have hypothetically proposed pumice rafts as an ideal substrate for the origin of life. Notable examples Pumice rafts drifted to Fiji in 1979 and 1984 from eruptions around Tonga, and some were reportedly wide. Volcanic activity in the South Pacific near Tonga on August 12, 2006 caused the emergence of a new island. The crew of the ''Maiken'', a yacht that had left the northern Tongan islands group of Vava'u in August ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcano, volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer to all explosive eruption products (correctly referred to as ''tephra''), including particles larger than 2 mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere. The force of the gases shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash is also produced when magma comes into contact with water during phreatomagmatic eruptions, causing the water to explosively flash to steam leading to shattering of magma. Once in the air, ash is transported by wind up to thousands of kilometres away. Due to its wide dispersal, ash can have a number of impacts on society, including animal a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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