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Summit
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A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. Mathematically, a summit is a maximum in elevation. The topographic terms acme, apex, peak, and zenith are synonymous, the UIAA definition is that a summit is independent if it has a prominence of 30 metres or more, it is a mountain if it has a prominence of at least 300 metres. This can be summarised as follows, A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top, Summit may also refer to the highest point along a line, trail, or route. In many parts of the western United States, the term refers to the highest point along a road, highway. For example, the highest point along Interstate 80 in California is referred to as Donner Summit while the highest point on Interstate 5 is Siskiyou Mountain Summit, geoid Hill List of highest mountains Maxima and minima Nadir Summit accordance Peak finder
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Topographic prominence
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It is a measure of the independence of a summit. A peaks key col is a point on this contour line. By convention, the prominence of Mount Everest, the Earths highest mountain, is taken to equal the elevation of its summit above sea level, if the peaks prominence is P metres, to get from the summit to any higher terrain one must descend at least P metres. Together with the convention for Mount Everest, this implies that the prominence of any island or continental highpoint is equal to its elevation above sea level, for every ridge connecting the peak to higher terrain, find the lowest point on the ridge. The key col is defined as the highest of these cols, the prominence is the difference between the elevation of the peak and the elevation of the key col. The following mental exercise may illustrate the meaning of topographic prominence, imagine you are standing at the top of a peak and imagine that an imaginary sea level rises to your feet. Now slowly lower the sea level and an imaginary island appears beneath your feet. Your island will grow and will merge with other islands that emerge, the parent peak may be either close or far from the subject peak. The summit of Mount Everest is the parent peak of Aconcagua at a distance of 17,755 km, the key col may also be close or far from the subject peak. The key col for Aconcagua is the Bering Strait at a distance of 13,655 km, the key col for the South Summit of Mount Everest is about 100 m distant. Prominence is interesting to many mountaineers because it is a measurement that is strongly correlated with the subjective significance of a summit. Peaks with low prominences are either subsidiary tops of some higher summit or relatively insignificant independent summits, peaks with high prominences tend to be the highest points around and are likely to have extraordinary views. Only summits with a sufficient degree of prominence are regarded as independent mountains, for example, the worlds second-highest mountain is K2. While Mount Everests South Summit is taller than K2, it is not considered an independent mountain because it is a subsummit of the main summit, many lists of mountains take topographic prominence as a criterion for inclusion, or cutoff. John and Anne Nuttalls The Mountains of England and Wales uses a cutoff of 15 m, in the contiguous United States, the famous list of fourteeners uses a cutoff of 300 ft /91 m. Also in the U. S.2000 feet of prominence has become a threshold that signifies that a peak has major stature. This generates lists of peaks ranked by prominence, which are different from lists ranked by elevation. Such lists tend to emphasize isolated high peaks, such as range or island high points, one advantage of a prominence-ranked list is that it needs no cutoff, since a peak with high prominence is automatically an independent peak
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Ultra-prominent peak
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An ultra-prominent peak, or Ultra for short, is defined as a mountain summit with a topographic prominence of 1,500 metres or more. There are approximately 1,524 such peaks on Earth, some peaks, such as the Matterhorn and Eiger, are not Ultras because they are connected to higher mountains by high cols and therefore do not achieve enough topographic prominence. The term Ultra is due to earth scientist Stephen Fry, from his studies of the prominence of peaks in Washington in the 1980s and his original term was ultra major mountain, referring to peaks with at least 5,000 ft of prominence. Currently,1,515 Ultras have been identified worldwide,637 in Asia,355 in North America,209 in South America,119 in Europe,84 in Africa,69 in Australasia and 39 in Antarctica. Many of the worlds largest mountains are Ultras, including Mount Everest, K2, Kilimanjaro, Mont Blanc, on the other hand, others such as the Eiger and the Matterhorn are not Ultras because they do not have sufficient prominence. In British Columbia, some of the mountains listed do not even have generally recognized names, a number of Ultras have yet to be climbed, with Sauyr Zhotasy, Mount Siple, and Gangkar Puensum being the most likely candidates for the most prominent unclimbed mountain in the world. All of the Seven Summits are Ultras by virtue of the fact that they are the points of large landmasses. Each has its key col at or near sea level, resulting in a value almost equal to its elevation. List of peaks by prominence gives the 125 most prominent peaks worldwide
4.
West New Britain Province
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West New Britain is a province of Papua New Guinea on the islands of New Britain. The area of the province in 20,387 km², West New Britain produces palm oil for export. There are seven major tribes, the Nakanai, Bakovi, Kove, Unea, Maleu, Kaulong and Arowe, people from West New Britain are widely referred to as Kombes throughout Papua New Guinea, in metonymic reference to the significant Kove people. There are substantial oil palm plantations on the north coast of the province especially in the Kimbe region, the Walindi dive resort near Kimbe is a significant tourist destination for overseas visitors to Papua New Guinea. There are two districts in the province, each district has one or more Local Level Government areas. For census purposes, the LLG areas are subdivided into wards, the province and each district is represented by a Member of the National Parliament. There is one provincial electorate and each district is an open electorate, the following table lists Members before and after the 2007 general election
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Papua New Guinea
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Its capital, located along its southeastern coast, is Port Moresby. The western half of New Guinea forms the Indonesian provinces of Papua, Papua New Guinea is one of the most culturally diverse countries in the world. There are 852 known languages in the country, of which 12 have no known living speakers, most of the population of more than 7 million people live in customary communities, which are as diverse as the languages. It is also one of the most rural, as only 18 percent of its live in urban centres. The country is one of the worlds least explored, culturally and geographically and it is known to have numerous groups of uncontacted peoples, and researchers believe there are many undiscovered species of plants and animals in the interior. Papua New Guinea is classified as an economy by the International Monetary Fund. Strong growth in Papua New Guineas mining and resource sector led to the becoming the sixth fastest-growing economy in the world in 2011. Growth was expected to slow once major resource projects came on line in 2015, mining remains a major economic factor, however. Local and national governments are discussing the potential of resuming mining operations in Panguna mine in Bougainville Province, nearly 40 percent of the population lives a self-sustainable natural lifestyle with no access to global capital. Most of the still live in strong traditional social groups based on farming. Their social lives combine traditional religion with modern practices, including primary education, at the national level, after being ruled by three external powers since 1884, Papua New Guinea established its sovereignty in 1975. This followed nearly 60 years of Australian administration, which started during the Great War and it became an independent Commonwealth realm with Queen Elizabeth II as its head of state and became a member of the Commonwealth of Nations in its own right. Archaeological evidence indicates that humans first arrived in Papua New Guinea around 42,000 to 45,000 years ago and they were descendants of migrants out of Africa, in one of the early waves of human migration. Agriculture was independently developed in the New Guinea highlands around 7000 BC, a major migration of Austronesian-speaking peoples to coastal regions of New Guinea took place around 500 BC. This has been correlated with the introduction of pottery, pigs, in the 18th century, traders brought the sweet potato to New Guinea, where it was adopted and became part of the staples. Portuguese traders had obtained it from South America and introduced it to the Moluccas, the far higher crop yields from sweet potato gardens radically transformed traditional agriculture and societies. Sweet potato largely supplanted the previous staple, taro, and resulted in a significant increase in population in the highlands. In 1901, on Goaribari Island in the Gulf of Papua, missionary Harry Dauncey found 10,000 skulls in the islands Long Houses, traders from Southeast Asia had visited New Guinea beginning 5,000 years ago to collect bird of paradise plumes
6.
Stratovolcano
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A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a profile and periodic explosive eruptions and effusive eruptions. The lava flowing from stratovolcanoes typically cools and hardens before spreading far due to high viscosity, the magma forming this lava is often felsic, having high-to-intermediate levels of silica, with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as 15 km, stratovolcanoes are sometimes called composite volcanoes because of their composite layered structure built up from sequential outpourings of eruptive materials. They are among the most common types of volcanoes, in contrast to the less common shield volcanoes, two famous stratovolcanoes are Krakatoa, best known for its catastrophic eruption in 1883 and Vesuvius, famous for its destruction of the towns Pompeii and Herculaneum in 79 CE. Both eruptions claimed thousands of lives, in modern times, Mount Saint Helens and Mount Pinatubo have erupted catastrophically. Existence of stratovolcanoes has not been proved on other bodies of the solar system with one exception. Their existence was suggested for some isolated massifs on Mars, e. g. Zephyria Tholus, stratovolcanoes are common at subduction zones, forming chains along plate tectonic boundaries where oceanic crust is drawn under continental crust or another oceanic plate. The release of water from hydrated minerals is termed dewatering, and occurs at pressures and temperatures for each mineral. The magma then rises through the crust, incorporating silica-rich crustal rock, when the magma nears the top surface, it pools in a magma chamber under or within the volcano. There, the low pressure allows water and other volatiles dissolved in the magma to escape from solution, as occurs when a bottle of carbonated water is opened. Once a critical volume of magma and gas accumulates, the obstacle of the cone is overcome. In recorded history, explosive eruptions at subduction zone volcanoes have posed the greatest hazard to civilizations. Subduction-zone stratovolcanoes, such as Mount St. Helens, Mount Etna and Mount Pinatubo, typically erupt with explosive force, as a consequence, the tremendous internal pressures of the trapped volcanic gases remain in the pasty magma. Following the breaching of the chamber, the magma degasses explosively. The gases and water out with speed and force. Since 1600 CE, nearly 300,000 people have killed by volcanic eruptions. Most deaths were caused by flows and mudflows, deadly hazards that often accompany explosive eruptions of subduction-zone stratovolcanoes
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Volcanic arc
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A volcanic arc is a chain of volcanoes formed above a subducting plate, positioned in an arc shape as seen from above. Offshore volcanoes form islands, resulting in an island arc. Generally, volcanic arcs result from the subduction of a tectonic plate under another tectonic plate. The oceanic plate is saturated with water, and volatiles such as water drastically lower the point of the mantle. As the oceanic plate is subducted, it is subjected to greater and greater pressures with increasing depth and this pressure squeezes water out of the plate and introduces it to the mantle. Here the mantle melts and forms magma at depth under the overriding plate, the magma ascends to form an arc of volcanoes parallel to the subduction zone. The Hawaiian Islands form a typical hotspot chain, the islands to the northwest are smaller and more lush than the recently created Hawaii island itself. Hotspot volcanoes are known as intra-plate volcanoes, and the islands they create are known as Volcanic Ocean Islands. Volcanic arcs do not generally such a simple age-pattern. There are two types of volcanic arcs, oceanic arcs form when oceanic crust subducts beneath other oceanic crust on an adjacent plate, continental arcs form when oceanic crust subducts beneath continental crust on an adjacent plate, creating an arc-shaped mountain belt. In some situations, a subduction zone may show both aspects along its length, as part of a plate subducts beneath a continent and part beneath adjacent oceanic crust. Volcanoes are present in almost any mountain belt, but this does not make it a volcanic arc, often there are isolated, but impressively huge volcanoes in a mountain belt. For instance, Vesuvius and the Etna volcanoes in Italy are part of separate, the active front of a volcanic arc is the belt where volcanism develops at a given time. Active fronts may move over time, changing their distance from the trench as well as their width. This loss of water is due to the destabilization of the mineral chlorite at approximately 40–60 km depth. On the subducting side of the arc is a deep and narrow oceanic trench. This trench is created by the pull of the relatively dense subducting plate pulling the leading edge of the plate downward. Multiple earthquakes occur along this boundary with the seismic hypocenters located at increasing depth under the island arc
8.
Volcanic belt
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A volcanic belt is a large volcanically active region. Other terms are used for areas of activity, such as volcanic fields. Volcanic belts are found above zones of high temperature where magma is created by partial melting of solid material in the Earths crust. These areas usually form along tectonic plate boundaries at depths of 10–50 km, the deeply deformed and eroded remnants of ancient volcanic belts are found in volcanically inactive regions such as the Canadian Shield. It contains over 150 volcanic belts that range from 600 to 1200 million years old and these are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that form what are known as greenstone belts. They are thought to have formed at ancient oceanic spreading centers, the Abitibi greenstone belt in Ontario and Quebec, Canada is one of the worlds largest greenstone belts. Volcanic belts may be formed by multiple tectonic settings, an oceanic plate ordinarily slides underneath a continental plate, this often creates an orogenic zone with many volcanoes and earthquakes. In a sense, subduction zones are the opposite of divergent boundaries, areas where material rises up from the mantle, Volcanic belts may also be formed by hotspots, which is a location on the Earths surface that has experienced active volcanism for a long period of time. These volcanic belts are called volcanic chains, but more recently some geologists, such as Gillian Foulger view upper-mantle convection as a cause. This in turn has re-raised the antipodal pair impact hypothesis, the idea that pairs of opposite hot spots may result from the impact of a large meteor. Geologists have identified some 40-50 such hotspots around the globe, with Hawaii, Réunion, Yellowstone, Galápagos, and Iceland overlying the most currently active. An example of a volcanic belt is the Anahim Volcanic Belt in British Columbia, Canada. Most hotspot volcanoes are basaltic because they erupt through oceanic lithosphere, as a result, they are less explosive than subduction zone volcanoes, which have high water contents. Where hotspots occur under continental crust, basaltic magma is trapped in the less dense continental crust and these rhyolites can be quite hot and form violent eruptions, despite their low water content. For example, the Yellowstone Caldera was formed by some of the most powerful explosions in geologic history. Andean Volcanic Belt Garibaldi Volcanic Belt Taupo Volcanic Zone Plate tectonics
9.
Types of volcanic eruptions
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Several types of volcanic eruptions—during which lava, tephra, and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed, some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions, the most well-observed are magmatic eruptions, which involve the decompression of gas within magma that propels it forward. Phreatomagmatic eruptions are another type of eruption, driven by the compression of gas within magma. Within these wide-defining eruptive types are several subtypes, the weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions, subglacial and phreatic eruptions are defined by their eruptive mechanism, and vary in strength. An important measure of strength is Volcanic Explosivity Index, an order of magnitude scale ranging from 0 to 8 that often correlates to eruptive types. Explosive eruptions are characterized by gas-driven explosions that propels magma and tephra, effusive eruptions, meanwhile, are characterized by the outpouring of lava without significant explosive eruption. Volcanic eruptions vary widely in strength, on the one extreme there are effusive Hawaiian eruptions, which are characterized by lava fountains and fluid lava flows, which are typically not very dangerous. On the other extreme, Plinian eruptions are large, violent, volcanoes are not bound to one eruptive style, and frequently display many different types, both passive and explosive, even the span of a single eruptive cycle. Volcanoes do not always erupt vertically from a crater near their peak. Some volcanoes exhibit lateral and fissure eruptions, notably, many Hawaiian eruptions start from rift zones, and some of the strongest Surtseyan eruptions develop along fracture zones. Scientists believed that pulses of magma mixed together in the chamber before climbing upward—a process estimated to several thousands of years. But Columbia University volcanologists found that the eruption of Costa Rica’s Irazú Volcano in 1963 was likely triggered by magma that took a route from the mantle over just a few months. The volcanic explosivity index is a scale, from 0 to 8 and it is used by the Smithsonian Institutions Global Volcanism Program in assessing the impact of historic and prehistoric lava flows. It operates in a way similar to the Richter scale for earthquakes, the vast majority of volcanic eruptions are of VEIs between 0 and 2. Volcanic eruptions by VEI index Magmatic eruptions produce juvenile clasts during explosive decompression from gas release, Hawaiian eruptions are a type of volcanic eruption, named after the Hawaiian volcanoes with which this eruptive type is hallmark. Hawaiian eruptions are the calmest types of events, characterized by the effusive eruption of very fluid basalt-type lavas with low gaseous content
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