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Grímsvötn Volcano Showing Plume - May 22
Grímsvötn (; ''vötn'' = "waters", singular: ) is a volcano with a (partially subglacial) fissure system located in Vatnajökull National Park, Iceland. The volcano itself is completely subglacial and located under the northwestern side of the Vatnajökull ice cap. The subglacial caldera is at , at an elevation of . Beneath the caldera is the magma chamber of the Grímsvötn volcano. Grímsvötn is a basaltic volcano which has the highest eruption frequency of all the volcanoes in Iceland and has a southwest-northeast-trending fissure system. The massive climate-impacting Laki fissure eruption of 1783–1784 was a part of the same fissure system. Grímsvötn was erupting at the same time as Laki during 1783, but continued to erupt until 1785. Because most of the volcanic system lies underneath Vatnajökull, most of its eruptions have been subglacial and the interaction of magma and meltwater from the ice causes phreatomagmatic explosive activity. Jökulhlaup Eruptions in the cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Volcanoes In Iceland
This list of volcanoes in Iceland includes active and dormant volcanic mountains, of which 18 have erupted since human settlement of Iceland began around 900 AD. __TOC__ List Volcanic zones and systems Iceland has four major volcanic zones surrounding an hypothetical hotspot: * the Reykjanes zone (RVZ), subdivided into the Reykjanes Ridge (RR) (the Mid-Atlantic Ridge South of Iceland) and the Reykjanes Volcanic Belt (RVB) (on the main island); * the West Volcanic Zone (WVZ); * the East Volcanic Zone (EVZ) (extended to the Westman Islands, South of the main island); * the North Volcanic Zone (NVZ). The Mid-Iceland Belt (MIB) connects them across central Iceland. In Iceland's East Volcanic Zone (EVZ), the central volcanoes, Vonarskarð and Hágöngur belong to the same volcanic system; this also applies to Bárðarbunga and Hamarinn, and to Grímsvötn and Þórðarhyrna. North of Iceland, the Mid-Atlantic Ridge is called Kolbeinsey Ridge (KR) and is connected to the No ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1996 Eruption Of Gjálp
Gjálp () is a hyaloclastite ridge (tindar) in Iceland under the Vatnajökull glacier shield. It originated in an eruption series in 1996 and is probably part of the Grímsvötn volcanic system,Snæbjörn Guðmundsson: ''Vegavísir um jarðfræði Íslands.'' Reykjavík 2015, p. 280-281 though not all the scientists involved are of this opinion. Importance The eruption was of imminent importance, because it was for the first time that a subglacial eruption under a thick ice cover as well as the connected jökulhlaup could be observed and analyzed by modern technique. Geography Eruption location The subglacial eruption fissure is to be found in the northwest corner of Vatnajökull ice cap more or less half way between the central volcanoes Bárðarbunga and Grímsvötn.Helgi Björnsson, etal: ''Glacier-volcano interactions deduced by SAR-inferometry. Journal of Geology.'' Vol. 47, no. 156 (2001). Retrieved 8 August 2020. Vatnajökull ice cap The Vatnajökull glacier which co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2011 Eruption Of Grímsvötn
The 2011 eruption of Grímsvötn was a Plinian eruption of Grímsvötn, Iceland's most active volcano, which caused disruption to air travel in Northwestern Europe from 22–25 May 2011. The last eruption of Grímsvötn was in 2004, with the previous most powerful eruptions in 1783, 1873 and 1902. The Grímsvötn eruption was the largest eruption in Iceland for 50 years. Timeline The eruption is estimated to have started under the glacier at around 17:30 UTC on 21 May 2011 when an intense spike in tremor activity was detected. At around 19:00 UTC, the eruption broke the ice cover of the glacier and started spewing volcanic ash into the air. The eruption plume quickly rose to . A series of small earthquakes had commenced at the time of eruption. Glacial flooding was anticipated, which normally occurs within 10–12 hours after eruption, but it never occurred as a flood had occurred the previous autumn, meaning a smaller chance of another flood appearing. On 25 May, the Icela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universal Coordinated Time
Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about one second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used prime meridian) and is not adjusted for daylight saving time. It is effectively a successor to Greenwich Mean Time (GMT). The coordination of time and frequency transmissions around the world began on 1 January 1960. UTC was first officially adopted as CCIR Recommendation 374, ''Standard-Frequency and Time-Signal Emissions'', in 1963, but the official abbreviation of UTC and the official English name of Coordinated Universal Time (along with the French equivalent) were not adopted until 1967. The system has been adjusted several times, including a brief period during which the time-coordination radio signals broadcast both UTC and "Stepped Atomic Time (SAT)" before a new UTC was adopted in 1970 and implemented in 1972. This change also a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grímsvötn Volcano Showing Plume - May 22
Grímsvötn (; ''vötn'' = "waters", singular: ) is a volcano with a (partially subglacial) fissure system located in Vatnajökull National Park, Iceland. The volcano itself is completely subglacial and located under the northwestern side of the Vatnajökull ice cap. The subglacial caldera is at , at an elevation of . Beneath the caldera is the magma chamber of the Grímsvötn volcano. Grímsvötn is a basaltic volcano which has the highest eruption frequency of all the volcanoes in Iceland and has a southwest-northeast-trending fissure system. The massive climate-impacting Laki fissure eruption of 1783–1784 was a part of the same fissure system. Grímsvötn was erupting at the same time as Laki during 1783, but continued to erupt until 1785. Because most of the volcanic system lies underneath Vatnajökull, most of its eruptions have been subglacial and the interaction of magma and meltwater from the ice causes phreatomagmatic explosive activity. Jökulhlaup Eruptions in the cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deformation (volcanology)
In volcanology, deformation is any change in the shape of a volcano or the land surrounding it. This can be in the form of inflation, which is a response to pressurization, or deflation, which is a response to depressurization. Inflation is represented by swelling of the ground surface, a volcanic edifice, or a subsurface magma body. It can be caused by magma accumulation, exsolution of volatiles, geothermal processes, heating, and tectonic compression. Deflation is represented by shrinking of the ground surface, a volcanic edifice, or a subsurface magma body. It can be caused by magma withdrawal (related to intrusion or eruption), volatile escape, thermal contraction, phase changes during crystallization, and tectonic extension. Deformation is a key indicator of pre-eruptive unrest at many active volcanoes. The term bradyseism is used in the volcanological literature to mean the vertical ground movements associated with the Phlegraean Fields volcanic area west of Naples, Ital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harmonic Tremor
A harmonic tremor is a sustained release of seismic and infrasonic energy typically associated with the underground movement of magma, the venting of volcanic gases from magma, or both. It is a long-duration release of seismic energy, with distinct spectral lines, that often precedes or accompanies a volcanic eruption. More generally, a volcanic tremor is a sustained signal that may or may not possess these harmonic spectral features. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquakes and explosions. The relation between long-period events and an imminent eruption was first observed by Bernard Chouet, a volcanologist who was working at the United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States ... [...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] |
NASA Photo Grímsvötn Nov
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown managemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
