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Hunga Tonga–Hunga Haʻapai
Hunga Tonga–Hunga Haʻapai () is a submarine volcano in the South Pacific located about south of the submarine volcano of Fonuafoou and north of Tongatapu, Tonga's main island. It is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate.Gupta, Alok K. ''Igneous Rocks.'' Mumbai, India: Allied Publishers, 1998. It lies about above a very active seismic zone.Ewart, A.; Bryan, W.B.; and Gill, J.B. "Mineralogy and Geochemistry of the Younger Volcanic Islands of Tonga, S.W. Pacific." ''Journal of Petrology.'' 14:3 (1973). The volcano rises around 2,000 m from the seafloor and has a caldera which – on the eve of the 2022 eruption – was roughly 150 m below sea level and 4 km at its widest extent. The only major above-water part of the volcano are the twin uninhabited islands of Hunga Tonga and Hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Volcanoes In Tonga ...
This is a list of active and extinct volcanoes in Tonga. References * See especiallFigure 1 * D. Stanley; South Pacific handbook * Government of Tonga, official 1962 land survey {{reflist Tonga Volcanoes 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesosphere
The mesosphere (; ) is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere. In the mesosphere, temperature decreases as altitude increases. This characteristic is used to define its limits: it begins at the top of the stratosphere (sometimes called the stratopause), and ends at the mesopause, which is the coldest part of Earth's atmosphere, with temperatures below . The exact upper and lower boundaries of the mesosphere vary with latitude and with season (higher in winter and at the tropics, lower in summer and at the poles), but the lower boundary is usually located at altitudes from above sea level, and the upper boundary (the mesopause) is usually from . The stratosphere and mesosphere are sometimes collectively referred to as the "middle atmosphere", which spans altitudes approximately between above Earth's surface. The mesopause, at an altitude of , separates the mesosphere from the thermosphere—the second-outermost lay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geophysical Research Letters
''Geophysical Research Letters'' is a biweekly peer-reviewed scientific journal of geoscience published by the American Geophysical Union that was established in 1974. The editor-in-chief is Harihar Rajaram. Aims and scope The journal aims for rapid publication of concise research reports on one or more of the disciplines covered by the American Geophysical Union, such as atmospheric sciences, solid Earth, space science, oceanography, hydrology, land surface processes, and the cryosphere. The journal also publishes invited reviews that cover advances achieved during the past two or three years. The target readership is the earth science community, the broader scientific community, and the general public. Abstracting and indexing This journal is abstracted and indexed in: According to the 2020 ''Journal Citation Reports'', the journal has a 2019 impact factor of 4.58. ''Geophysical Research Letters'' was also the 5th most cited publication on climate change between 1999 and 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basaltic Andesite
Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central America and the Andes of South America. Description Basaltic andesite is a fine-grained (aphanitic) igneous rock that is moderately low in silica and low in alkali metal oxides. It is not separately defined in the QAPF classification, which is based on the relative percentages of quartz, alkali feldspar, plagioclase feldspar, and feldspathoids, but would fall in the basalt-andesite field. This corresponds to rock in which feldspathoid makes up less than 10% and quartz less than 20% of the total QAPF fraction, and in which at least 65% of the feldspar is plagioclase. Basaltic andesite would be further distinguished from basalt and andesite by a silica content between 52% and 57%. Although classification by mineral content is preferred by the ... [...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] |
Andesite
Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende. Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. Along with basalts, andesites are a component of the Martian crust. The name ''andesite'' is derived from the Andes mountain range, where this rock type is found in abundance. It was first applied by Christian Leopold von Buch in 1826. Description Andesite is an aphanitic (fine-grained) igneous rock that is intermediate in its content of silica and low in alkali metals. It has less than 20% quartz and 10% feldspathoid by volume, with at least 65% of the fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subaerial
In natural science, subaerial (literally "under the air"), has been used since 1833,Subaerial in the Merriam-Webster dictionary. notably in and , to describe features and events occurring or formed on or near the 's land surface. They are thus exposed to Earth's atmosphere. This may be contrasted with '' subaqueous'' events or features located below a water surface, '' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Geophysical Union
The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international fields within the Earth and space sciences. The geophysical sciences involve four fundamental areas: atmospheric and ocean sciences; solid-Earth sciences; hydrologic sciences; and space sciences. The organization's headquarters is located on Florida Avenue in Washington, D.C. History The AGU was established in December 1919 by the National Research Council (NRC) to represent the United States in the International Union of Geodesy and Geophysics (IUGG), and its first chairman was William Bowie of the United States Coast and Geodetic Survey (USCGS). For more than 50 years, it operated as an unincorporated affili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eos (magazine)
''Eos, Transactions, American Geophysical Union'', is a weekly magazine of Earth science published by John Wiley & Sons for the American Geophysical Union (AGU). The magazine, based in Washington, DC, publishes news, book reviews, AGU journal and meeting abstracts, meeting programs and reports, a comprehensive meetings calendar, and announcements of grants, fellowships, and employment opportunities, as well as peer-reviewed articles on current research and on the relationship of geoscience to social and political questions. Since 2015 it is published in magazine form and is available electronically. A hardcover edition of ''Eos'' is published once each year and contains the articles, news, and editorials from the tabloid issues. ''Eos'' accepts both display and classified advertising. History ''Transactions of the American Geophysical Union'' began publication as proceedings of the organization's meetings. In 1920, the first volume was reprinted from volume 6, number 10 of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldera
A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is gone. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a Volcanic crater, crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur each century, the formation of a caldera is a rare event, occurring only a few times per century. Only seven caldera-forming collapses are known to have occurred between 1911 and 2016. More recently, a caldera collapse occurred at Kīlauea, Hawaii in 2018. Etymology The term ''caldera'' comes from Spanish language, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Island
Geologically, a high island or volcanic island is an island of volcanic origin. The term can be used to distinguish such islands from low islands, which are formed from sedimentation or the uplifting of coral reefs (which have often formed on sunken volcanos). Definition and origin There are a number of "high islands" that rise no more than above sea level, often classified as "islets or rocks", while some low islands, such as Banaba, Henderson Island, Makatea, Nauru, and Niue, as uplifted coral islands, rise over above sea level. The two types of islands are often found in proximity to each other, especially among the islands of the South Pacific Ocean, where low islands are found on the fringing reefs that surround most high islands. Volcanic islands normally arise above a hotspot. Habitability High islands above a certain size usually have fresh groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Boundary
A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more Plate tectonics, lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a plane where many earthquakes occur, called the Wadati–Benioff zone. These collisions happen on scales of millions to tens of millions of years and can lead to volcanism, earthquakes, Orogeny, orogenesis, destruction of lithosphere, and Deformation (geology), deformation. Convergent boundaries occur between oceanic-oceanic lithosphere, oceanic-continental lithosphere, and continental-continental lithosphere. The geologic features related to convergent boundaries vary depending on crust types. Plate tectonics is driven by convection cells in the mantle. Convection cells are the result of heat generated by the radioactive decay of elements in the mantle escaping to the surface and the return of cool materials from the surfac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
