1.
Mount Tongariro
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Mount Tongariro is a compound volcano in the Taupo Volcanic Zone of the North Island of New Zealand. It is located 20 kilometres to the southwest of Lake Taupo, Mount Tongariro is part of the Tongariro volcanic centre, which consists of four massifs made of andesite, Tongariro, Kakaramea, Pihanga, and Ruapehu. The andesitic eruptions formed Tongariro, a stratovolcano, reaching a height of 1,978 metres. Tongariro is composed of layers of lava and tephra and first erupted 275,000 years ago. Tongariro consists of at least 12 cones, Ngauruhoe, while often regarded as a separate mountain, is geologically a cone of Tongariro. It is also the most active vent, having erupted more than 70 times since 1839, activity has also been recorded at other vents in recent history. Te Māri Craters erupted in 2012, for the first time since 1897, red Crater last erupted ash in 1926 and contains active fumaroles. There are many craters on the massif, water has filled some of these to form the Blue Lake. Unlike nearby Mt. Ruapehu, no glaciers exist on Tongariro today, however, geomorphological evidence in the form of moraines and cirques indicates the former presence of mountain glaciers. Mount Tongariro is in the Tongariro National Park, New Zealands first national park and it was set aside in 1887 by Te Heuheu Tukino IV, paramount chief of the Māori Ngati Tuwharetoa iwi and made a national park in order to preserve its natural beauty. The park also includes the peaks of Ngauruhoe and Ruapehu, both of which lie to the southwest of Tongariro, the national park is a dual World Heritage Site for its outstanding natural and intangible cultural values. The popular hiking route called Tongariro Alpine Crossing passes between Tongariro and Ngauruhoe, Mount Tongariro and its surroundings are also one of the several locations which Peter Jackson chose to shoot the The Lord of the Rings film trilogy. At 11,50 pm on 6 August 2012, Mt Tongariro had what was believed to be a hydrothermal eruption after a month of increased activity. The eruption occurred at the Te Māri Craters, which had dormant since 1897. The eruption occurred in a new vent below the Upper Te Māri crater, an ash cloud 6.1 kilometres high deposited ash into the surrounding area, especially to the east of the volcano. The ash cloud travelled 250 kilometres in four hours, NIWA reported the ash cloud contained about 10,000 cubic metres of ash, and that the ash cloud was 25 kilometres long and 15 kilometres wide 39 minutes after the eruption. Ash and the smell of sulphur was reported in Napier and Hastings, the smell of sulphur was also reported in Wellington, Nelson and Blenheim. A layer of ash 10–15 mm thick settled on farmland 5 to 10 kilometres east of Mount Tongariro, particle sizes were between 2 and 3mm
2.
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
3.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
4.
North Island
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The North Island or Te Ika-a-Māui is one of the two main islands of New Zealand, separated from the slightly larger but much less populous South Island by Cook Strait. The islands area is 113,729 square kilometres, making it the worlds 14th-largest island and it has a population of 3,596,200. Twelve main urban areas are in the North Island, about 77% of New Zealands population lives in the North Island. Although the island has been known as the North Island for many years, in 2009 the New Zealand Geographic Board found that, along with the South Island, after a public consultation, the board officially named the island North Island or Te Ika-a-Maui in October 2013. In prose, the two islands of New Zealand are called the North Island and the South Island, with the definite articles. It is normal to use the preposition in rather than on, for example Hamilton is in the North Island, maps, headings, tables and adjectival expressions use North Island without the. According to Māori mythology, the North and South Islands of New Zealand arose through the actions of the demigod Māui, Māui and his brothers were fishing from their canoe when he caught a great fish and pulled it from the sea. While he was not looking his brothers fought over the fish and this great fish became the North Island and thus a Māori name for the North Island is Te Ika-a-Māui. The mountains and valleys are believed to have formed as a result of Māuis brothers hacking at the fish. Until the early 20th Century, an alternative Māori name for the North Island was Aotearoa, in present usage, Aotearoa is a collective name for New Zealand as a whole. The sub-national GDP of the North Island was estimated at US$102.863 billion in 2003, the island has an extensive flora and bird population, with numerous National Parks and other protected areas. Nine local government regions cover the North Island and all its adjacent islands, healthcare in the North Island is provided by fifteen District Health Boards. Organised around geographical areas of varying sizes, they are not coterminous with the Local Government Regions
5.
New Zealand
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New Zealand /njuːˈziːlənd/ is an island nation in the southwestern Pacific Ocean. The country geographically comprises two main landmasses—the North Island, or Te Ika-a-Māui, and the South Island, or Te Waipounamu—and around 600 smaller islands. New Zealand is situated some 1,500 kilometres east of Australia across the Tasman Sea and roughly 1,000 kilometres south of the Pacific island areas of New Caledonia, Fiji, because of its remoteness, it was one of the last lands to be settled by humans. During its long period of isolation, New Zealand developed a distinct biodiversity of animal, fungal, the countrys varied topography and its sharp mountain peaks, such as the Southern Alps, owe much to the tectonic uplift of land and volcanic eruptions. New Zealands capital city is Wellington, while its most populous city is Auckland, sometime between 1250 and 1300 CE, Polynesians settled in the islands that later were named New Zealand and developed a distinctive Māori culture. In 1642, Dutch explorer Abel Tasman became the first European to sight New Zealand, in 1840, representatives of Britain and Māori chiefs signed the Treaty of Waitangi, which declared British sovereignty over the islands. In 1841, New Zealand became a colony within the British Empire, today, the majority of New Zealands population of 4.7 million is of European descent, the indigenous Māori are the largest minority, followed by Asians and Pacific Islanders. Reflecting this, New Zealands culture is derived from Māori and early British settlers. The official languages are English, Māori and New Zealand Sign Language, New Zealand is a developed country and ranks highly in international comparisons of national performance, such as health, education, economic freedom and quality of life. Since the 1980s, New Zealand has transformed from an agrarian, Queen Elizabeth II is the countrys head of state and is represented by a governor-general. In addition, New Zealand is organised into 11 regional councils and 67 territorial authorities for local government purposes, the Realm of New Zealand also includes Tokelau, the Cook Islands and Niue, and the Ross Dependency, which is New Zealands territorial claim in Antarctica. New Zealand is a member of the United Nations, Commonwealth of Nations, ANZUS, Organisation for Economic Co-operation and Development, Pacific Islands Forum, and Asia-Pacific Economic Cooperation. Dutch explorer Abel Tasman sighted New Zealand in 1642 and called it Staten Landt, in 1645, Dutch cartographers renamed the land Nova Zeelandia after the Dutch province of Zeeland. British explorer James Cook subsequently anglicised the name to New Zealand, Aotearoa is the current Māori name for New Zealand. It is unknown whether Māori had a name for the country before the arrival of Europeans. Māori had several names for the two main islands, including Te Ika-a-Māui for the North Island and Te Waipounamu or Te Waka o Aoraki for the South Island. Early European maps labelled the islands North, Middle and South, in 1830, maps began to use North and South to distinguish the two largest islands and by 1907, this was the accepted norm. The New Zealand Geographic Board discovered in 2009 that the names of the North Island and South Island had never been formalised and this set the names as North Island or Te Ika-a-Māui, and South Island or Te Waipounamu
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
7.
Volcano
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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. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology, at the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Most divergent plate boundaries are at the bottom of the oceans, therefore, most volcanic activity is submarine, black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the temperature of the overlying mantle wedge. This magma tends to be very viscous due to its high content, so it often does not reach the surface. When it does reach the surface, a volcano is formed, typical examples of this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume and this theory is currently under criticism, however. The most common perception of a volcano is of a mountain, spewing lava and poisonous gases from a crater at its summit, however. The features of volcanoes are more complicated and their structure. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have features such as massive plateaus
8.
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
9.
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
10.
Taupo Volcanic Zone
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The Taupo Volcanic Zone is a highly active volcanic V-shaped area in the North Island of New Zealand that is spreading east–west at the rate of about 8 mm per year. It is named after Lake Taupo, the caldera of the largest volcano in the zone. There are numerous volcanic vents and geothermal fields in the zone, with Mount Ruapehu, Mount Ngauruhoe, the zones largest eruption since the arrival of Europeans was that of Mount Tarawera in 1886, which killed over 100 people. Early Maori would also have been affected by the much larger Kaharoa eruption from Tarawera around 1300 AD, the last major eruption from Lake Taupo, the Hatepe eruption, occurred in 181 AD. It is believed to have first emptied the lake then followed that feat with a flow that covered about 20,000 square kilometres of land with volcanic ash. A total of 120 km3 of material is believed to have been ejected, the date of this activity is known since the ash expulsion was sufficiently large to turn the sky red over Rome and China. Taupo erupted an estimated 1,170 km3 of material in its Oruanui eruption 26,500 years ago and this was Earths most recent eruption reaching VEI-8, the highest level on the Volcanic Explosivity Index. The Rotorua caldera has been dormant longer, with its main eruption occurring about 240,000 years ago, the Taupo Volcanic Zone is approximately 350 kilometres long by 50 kilometres wide. Mount Ruapehu marks its end, while the submarine Whakatane volcano is considered its northeastern limit. It forms a portion of the active Lau-Havre-Taupo back-arc basin. Although the back-arc basin continues to propagate to the southwest, with the South Wanganui Basin forming an initial back-arc basin, South of Kaikoura the plate boundary changes to a transform boundary with oblique continental collision uplifting the Southern Alps in the South Island. A subduction zone reappears southwest of Fiordland, at the corner of the South Island. Solander Island is an extinct volcano associated with subduction zone. Recent scientific work indicates that the Earths crust below the Taupo Volcanic Zone may be as little as 16 kilometres thick, a film of magma 50 kilometres wide and 160 kilometres long lies 10 kilometres under the surface. The geological record indicates some of the volcanoes in the area erupt infrequently but have large, violent. There is also some possible rifting in the Taupo Volcanic Zone, see also List of volcanoes in New Zealand#Taupo Volcanic Zone. The following Volcanic Centers belong to the Taupo Volcanic Zone, Rotorua, Okataina, Maroa, Taupo, Tongariro and Mangakino. The Okareka Embayment and the Tarawera Volcanic Complex are inside the Haroharo Caldera which in turn is inside the Okataina Ring Structure, from Newhall, the Waikato River course follows roughly the northern Maroa caldera rim on one side
