The Shape Of Our Land - AS Science 0952

Mt Ruapehu

The Maori definition for Mount Ruapehu is an ‘exploding-pit of noise’, a phrase that is suitable for this 2787-metre-tall volcano. Mt Ruapehu, is Stratovolcano, the highest active volcano in New Zealand and the most dangerous of the Plateau Volcano area, which covers the South-West from the Bay of Plenty to Mount Ruapehu in Central North Island. Consisting of six cones, and six creators. All of these surface features seen today are the result and combination of internal and external geological processes.

Internal Processes

Mt Ruapehu, formed by the edge of the Pacific Plate subducting under the edge of the Australian Plate, by collisions and movement. The Pacific Plate is made up of ocean crust which is the thinnest but densest, therefore it subducts under the Australian Plate. Water gets subducted with the ocean crust. The deeper the crust-rocks and water subduct, the hotter they get. When the Pacific Plate crust has subducted deep enough, about 20km deep, the water and crust rocks melt from the heat a pool of molten magma forms. This is assisted by the super steam water squeezed out from the subducted crust, this lowers the melting point of the crust rocks. Earth is made up of five major layers including the inner core, outer core, mantle, upper mantle and crust. The upper mantle of the Earth is approximately 1100C, a temperature so hot that the rock melts. This mixture of melted and partially melted crust rocks is called magma, which forces it way up through the cracks and erupts to form a volcano because of high pressure. The amount of silica in the magma and the depth of the crust through which the magma travels determines the scale of the volcano eruption. Mt Ruapehu is the highest peak in North Island at 2797m high; its height is made up of alternating skin layers of ash and lava Magma flow.

Mt Ruapehu volcanic features are formed by collisions and movement of tectonic plates in the Earth’s crust deep down. Creating molten rock, ash, and gases. This creates positive pressure in the earth, the pressure causing the matter to escape from an opening on the earth’s surface.

Earth is made up of five major layers including the inner core, outer core, mantle, upper mantle and crust. The upper mantle of the Earth is approximately 1100C, a temperature so hot that the rock melts to form a molten layer, causing the pieces of the Earth’s

External Processes

Mt Ruapehu has two large commercial ski fields, Whakapapa and Turoa. Whakapapa the largest ski area in New Zealand is situated on the northwest slopes of Mt Ruapehu. Turoa has a unique volcanic zone compared to other areas, it is situated on the Western-Slopes of Mt Ruapehu. Over 280,000 people from New Zealand and overseas, visit Mt Ruapehu each year (PRE covid-19).

All known volcanoes (including Lake Taupo) in New Zealand are monitored by GNS Science, a ‘alert level’ is determined based on its activity data. Mt. Ruapehu has, “2 web cameras, 10 seismographs and 6 microphones detect volcanic explosions, and 9 continuous GPS stations record ground deformation. Water and gas monitoring of the crater lake and airborne gas monitoring is also carried out regularly.” Impediment, maintained, monitored by GNS science 24/7; Volcanoes are monitored simply by cameras or visually in person. The Alert Level can determine whether is safe to visit a volcano.

Lake Taupo

Taupo is a ‘supervolcano’ located in the Taupo Volcanic Zone, in Central North Island of New Zealand. It is one of the worlds’ most frequently active and productive rhyolite caldera volcanoes. Taupo lake is a “caldera” volcano creator that has filled with water, one of the biggest lakes in New Zealand. The current volcano magma chamber is between 6 and 8 km below the lake surface.

Internal Geological Processes

Lake Taupo, formed by the edge of the Pacific Plate subducting under the edge of the Australian Plate, helped by gravity. The Pacific Plate is made up of ocean crust which is the thinnest but densest, therefore it subducts under the Australian Plate. Lake Taupo sits on a magma chamber 6-8km below the lake surface. Water gets subducted with the ocean crust. The deeper the crust-rocks and water subduct, the hotter they get. When the Pacific Plate crust has subducted deep enough, about 20km deep, the water and crust rocks melt from the heat a pool of molten magma forms. This is assisted by the super steam water squeezed out from the subducted crust, this lowers the melting point of the crust rocks. This mixture of melted and partially melted crust rocks is called magma, which forces it way up through the cracks and erupts to form a volcano because of high pressure. The amount of silica in the magma and the depth of the crust through which the magma travels determines the scale of the volcano eruption. Lake Taupo volcano is scilla-rich This type of volcano is called a “Caldera '' volcano, named after Spanish caldera, and Latin caldaria, meaning "cooking pot". This type of volcano “Caldera'' volcano produces viscous rhyolite and Silica-rich magma; it has more violent eruptions than cone volcanoes that are shorter. After a large eruption the Magma ``pot-chamber” is emptied, structural support for the layer/s above the magma chamber is lost. The ground surface then collapses downward into the emptied or partially emptied magma “Pot-like-chamber”, leaving a massive depression at the surface. Therefore filling with water, making NZ’s largest lake, Lake Taupo. Caldera collapses are very rare; there are only seven Caldera collapses known to have occurred since 1900, the total area that can collapse may be hundreds of square kilometres. Lake Taupo has a perimeter of approximately 193 kilometres and a maximum depth of 186 metres. It is drained by the Waikato River (New Zealand's longest river).

External Processes

All known volcanoes (including Lake Taupo) in New Zealand are monitored by GNS Science, a ‘alert level’ is determined based on its activity data. Lake Taupo has, “7 seismographs and 6 continuous GPS stations, and lake levelling at 22 sites.” Impediment, maintained, monitored by GNS science 24/7; Volcanoes are monitored simply by cameras or visually in person. The Alert Level can determine whether it is safe to visit a volcano.