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Central America Volcanic Arc
The Central American Volcanic Arc (often abbreviated to CAVA) is a chain of volcanoes which extends parallel to the Pacific coastline of the Central American Isthmus, from Mexico to Panama. This volcanic arc, which has a length of 1,100 kilometers (680 mi)Rose, W., Conway, F., Pullinger, C., Deino, A. and McIntosh, W., 1999. An improved age framework for late Quaternary silicic eruptions in northern Central America. ''Bulletin of Volcanology'', 61(1-2), pp.106-120. is formed by an active subduction zone, with the Cocos Plate subducting underneath the Caribbean Plate.Álvarez-Gómez, J., Meijer, P., Martínez-Díaz, J. and Capote, R., 2008. Constraints from finite element modeling on the active tectonics of northern Central America and the Middle America Trench. ''Tectonics'', 27(1) The region has been volcanically and geologically active for at least the past several million years. Numerous volcanoes are spread throughout various Central American countries; many have been active i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central America Volcanic Belt
Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as Middle Africa * Central America, a region in the centre of America continent * Central Asia, a region in the centre of Eurasian continent * Central Australia, a region of the Australian continent * Central Belt, an area in the centre of Scotland * Central Europe, a region of the European continent * Central London, the centre of London * Central Region (other) * Central United States, a region of the United States of America Specific locations Countries * Central African Republic, a country in Africa States and provinces * Blue Nile (state) or Central, a state in Sudan * Central Department, Paraguay * Central Province (Kenya) * Central Province (Papua New Guinea) * Central Province (Solomon Islands) * Central Province, Sri Lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Year
A year or annus is the orbital period of a planetary body, for example, the Earth, moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by change in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the planet, four seasons are generally recognized: spring, summer, autumn and winter. In tropical and subtropical regions, several geographical sectors do not present defined seasons; but in the seasonal tropics, the annual wet and dry seasons are recognized and tracked. A calendar year is an approximation of the number of days of the Earth's orbital period, as counted in a given calendar. The Gregorian calendar, or modern calendar, presents its calendar year to be either a common year of 365 days or a leap year of 366 days, as do the Julian calendars. For the Gregorian calendar, the average length of the calendar yea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santa María (volcano)
Santa María Volcano is a large active volcano in the western highlands of Guatemala, in the Quetzaltenango Department near the city of Quetzaltenango. The volcano was known as Gagxanul in the local K'iche' language, which means "Naked Volcano or Mountain", before the 16th century Spanish conquest of the region. The VEI-6 eruption of Santa María Volcano in 1902 was one of the three largest eruptions of the 20th century, after the 1912 Novarupta and 1991 Mount Pinatubo eruptions. It is also one of the five biggest eruptions of the past 200 (and most likely 300) years. Geological history Santa María Volcano is part of the Sierra Madre range of volcanoes, which extends along the western edge of Guatemala, separated from the Pacific Ocean by a broad plain. The volcanoes are formed by the subduction of the Cocos Plate under the Caribbean Plate, which led to the formation of the Central America Volcanic Arc. Eruptions at Santa María are estimated to have begun about 103 ka. C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1902
Events January * January 1 ** The Nurses Registration Act 1901 comes into effect in New Zealand, making it the first country in the world to require state registration of nurses. On January 10, Ellen Dougherty becomes the world's first registered nurse. ** Nathan Stubblefield demonstrates his wireless telephone device in Kentucky, United States. * January 8 – A train collision in the New York Central Railroad's Park Avenue Tunnel kills 17 people, injures 38, and leads to increased demand for electric trains and the banning of steam locomotives in New York City. * January 23 – Hakkōda Mountains incident: A snowstorm in the Hakkōda Mountains of northern Honshu, Japan, kills 199 during a military training exercise. * January 30 – The Anglo-Japanese Alliance is signed. February * February 11 – Police and universal suffrage demonstrators are involved in a physical altercation in Brussels, Belgium. * February 15 – The Berl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
October 25
Events Pre-1600 * 285 (or 286) – Execution of Saints Crispin and Crispinian during the reign of Diocletian, now the patron saints of leather workers, curriers, and shoemakers. * 473 – Emperor Leo I acclaims his grandson Leo II as ''Caesar'' of the East Roman Empire. *1147 – Seljuk Turks defeat German crusaders under Conrad III at the Battle of Dorylaeum. * 1147 – ''Reconquista'': After a siege of four months, crusader knights reconquer Lisbon. *1415 – Hundred Years' War: Henry V of England, with his lightly armoured infantry and archers, defeats the heavily armoured French cavalry in the Battle of Agincourt. 1601–1900 *1616 – Dutch sea-captain Dirk Hartog makes the second recorded landfall by a European on Australian soil, at the later-named Dirk Hartog Island off the West Australian coast. *1747 – War of the Austrian Succession: A British fleet under Admiral Edward Hawke defeats the French at the Second Battle of Cape Finis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotopes Of Argon
Argon (18Ar) has 26 known isotopes, from 29Ar to 54Ar and 1 isomer (32mAr), of which three are stable (36Ar, 38Ar, and 40Ar). On the Earth, 40Ar makes up 99.6% of natural argon. The longest-lived radioactive isotopes are 39Ar with a half-life of 268 years, 42Ar with a half-life of 32.9 years, and 37Ar with a half-life of 35.04 days. All other isotopes have half-lives of less than two hours, and most less than one minute. The least stable is 29Ar with a half-life of approximately seconds. The naturally occurring 40K, with a half-life of 1.248 years, decays to stable 40Ar by electron capture (10.72%) and by positron emission (0.001%), and also transforms to stable 40Ca via beta decay (89.28%). These properties and ratios are used to determine the age of rocks through potassium–argon dating. Despite the trapping of 40Ar in many rocks, it can be released by melting, grinding, and diffusion. Almost all of the argon in the Earth's atmosphere is the product of 40K decay, since 99 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotopes Of Carbon
Carbon (6C) has 15 known isotopes, from to , of which and are stable. The longest-lived radioisotope is , with a half-life of years. This is also the only carbon radioisotope found in nature—trace quantities are formed cosmogenically by the reaction + → + . The most stable artificial radioisotope is , which has a half-life of . All other radioisotopes have half-lives under 20 seconds, most less than 200 milliseconds. The least stable isotope is , with a half-life of . List of isotopes , - , , style="text-align:right" , 6 , style="text-align:right" , 2 , , [] , proton emission, 2p , Subsequently decays by double proton emission to for a net reaction of → + 4 , 0+ , , , - , rowspan=3, , rowspan=3 style="text-align:right" , 6 , rowspan=3 style="text-align:right" , 3 , rowspan=3, , rowspan=3, , β+ () , , rowspan=3, 3/2− , rowspan=3, , rowspan=3, , - , β+α () , Immediately decays by proton emission to for a net reaction of → ... [...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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during 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 and hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Dome
In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth are lava dome forming. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day) The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite. Existence of lava domes has been suggested for some domed structures on ... [...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 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 ', and Latin ', meaning " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
