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Öræfajökull
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 settlement of Iceland, original Norse settlers named the volcano KnappafellsjÇ«kull (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 Route 1 (Iceland), Ring Road between Höfn à Hornafirði, Höfn and VÃk à Mýrdal, VÃk. It is the largest active volcano in the country, and on the volcanic crater, summit crater's north-western rim is Hvannadalshnúkur, the highest peak in Iceland at . Geographically, Öræfajökull as the glacier, is considered part of Vatnajökull, and the area covered by g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vatnajökull National Park
Vatnajökull National Park ( ) is one of three national parks in Iceland, and is the largest one. It encompasses all of Vatnajökull glacier and extensive surrounding areas. These include the national parks previously existing at Skaftafell in the southwest and Jökulsárgljúfur in the north. The unique qualities of Vatnajökull National Park are primarily its great variety of landscape features, created by the combined forces of rivers, glacial ice, and volcanic and geothermal activity. The park spans 14% of the country's area and is Europe's second largest national park in terms of area after Yugyd Va in the Ural Mountains of Russia. The glacier itself is the largest in Europe at . In 2019 the park was enlarged to the north. On 5 July 2019 Vatnajökull National Park was inscribed as a World Heritage Site. History Vatnajökull National Park was established on 7 June 2008. When established, the park covered an area of 12,000 km2, but with later additions of LakagÃga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East Volcanic Zone Of Iceland
The geological deformation of Iceland is the way that the rocks of the island of Iceland are changing due to tectonic forces. The geological deformation help to explain the location of earthquakes, volcanoes, fissures, and the shape of the island. Iceland is the largest landmass () situated on an oceanic ridge. It is an elevated plateau of the sea floor, situated at the crossing of the Mid-Atlantic Ridge and the Greenland-Iceland-Scotland ridge. It lies along an oceanic divergent plate boundary: the western part of Iceland sits on the North American Plate and the eastern part sits on the Eurasian Plate. The Reykjanes Ridge of the Mid-Atlantic ridge system in this region crosses the island from southwest and connects to the Kolbeinsey Ridge in the northeast. Iceland is geologically young: all rocks there were formed within the last 25 million years. It started forming in the Early Miocene sub-epoch, but the oldest rocks found at the surface of Iceland are from the Middle Miocene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vatnajökull
Vatnajökull ( Icelandic pronunciation: , literally "Glacier of Lakes"; sometimes translated as Vatna Glacier in English) is the largest and most voluminous ice cap in Iceland, and the second largest in area in Europe after the Severny Island ice cap of Novaya Zemlya. It is in the south-east of the island, covering approximately 10% of the country. Size With an area of 7,700 km2, Vatnajökull is the second largest ice cap in Europe by volume (about 3,000 km3) and area (after the still larger Severny Island ice cap of Novaya Zemlya, Russia, which is in the extreme northeast of Europe). On 7 June 2008, it became a part of the Vatnajökull National Park. The average thickness of the ice is , with a maximum thickness of . Iceland's highest peak, Hvannadalshnúkur (), as part of the Öræfajökull, is in the southern periphery of Vatnajökull, near Skaftafell. Peaks Hrútsfjallstindar is a series of Icelandic peaks rising from Vatnajökull between SvÃnafellsjök ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix (geology), groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite. Its high silica content makes rhyolitic magma extremely viscosity, viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been used extensively for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olivine Basalt
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron ( mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene
The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing Ice age, glacial cycles of the Quaternary, and is equivalent to Marine isotope stages, Marine Isotope Stage 1. The Holocene correlates with the last maximum axial tilt towards the Sun of the Earth#Axial tilt and seasons, Earth's obliquity. The Holocene corresponds with the rapid proliferation, growth, and impacts of the human species worldwide, including Recorded history, all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban culture, urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global significance for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tephra
Tephra is fragmental material produced by a Volcano, 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. 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. Tephrochronology is a geochronological technique that uses discrete layers of tephra—volcanic ash from a single eruption—to create a chronological framework in which Paleoecology, paleoenvironmental or Archaeology, archaeological records can be placed. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1991 Eruption Of Mount Pinatubo
The 1991 eruption of Mount Pinatubo in the Philippines' Luzon Volcanic Arc was the second-largest volcanic eruption of the 20th century, behind only the 1912 eruption of Novarupta in Alaska. Eruptive activity began on April 2 as a series of phreatic eruption, phreatic explosions from a fissure that opened on the north side of Mount Pinatubo. Seismographs were set up and began monitoring the volcano for earthquakes. In late May, the number of seismic events under the volcano fluctuated from day-to-day. Beginning June 6, a swarm of progressively shallower earthquakes accompanied by Deformation (volcanology), inflationary tilt on the upper east flank of the mountain, culminated in the extrusion of a small lava dome. On June 12, the volcano's first spectacular eruption sent an eruption column, ash column into the atmosphere. Additional explosions occurred overnight and the morning of June 13. Seismic activity during this period became intense. When even more highly gas-charged m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breiðamerkurjökull
Breiðamerkurjökull (, ) is an outlet glacier of the larger glacier of Vatnajökull and a piedmont glacier in the southern part of Vatnajökull National Park, Iceland. Emerging as a tongue of the Vatnajökull, it ends in two lagoons, famous Jökulsárlón and smaller and less known Breiðárlón. Over time, it has gradually been breaking down. As the icebergs break away from the tongue of the glacier, they drift slowly to the mouth of the lagoon and eventually join the ocean. They are stated to float in the deep lagoon for 5 years, which is around deep and spreads over an area of . It was near the ring road until 35 years ago before retreating rapidly and forming the Jökulsárlón lagoon. The high Breiðamerkurfjall mountain was enclosed by the Breiðamerkurjökull and Fjallsjökull before the drifting started and formed the Breiðárlón lagoon, which is not as dramatic as the Jökulsárlón lagoon. The location has been used for many films and commercials. The glacier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Explosivity Index
The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega-colossal") are used to determine the explosivity value. The scale is open-ended with the largest eruptions in history given a magnitude of 8. A value of 0 is given for non-explosive eruptions, defined as less than of tephra ejected; and 8 representing a supervolcanic eruption that can eject (240 cubic miles) of tephra and have a cloud column height of over . The scale is logarithmic, with each interval on the scale representing a tenfold increase in observed ejecta criteria, with the exception of between VEI-0, VEI-1 and VEI-2. Classification With indices running from 0 to 8, the VEI associated with an eruption is dependent on how much volcanic materia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
