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25-472: Lake Taupō (also spelled Taupo ; Māori : Taupō-nui-a-Tia or Taupōmoana ) is a large crater lake in New Zealand 's North Island , located in the caldera of Taupō Volcano . The lake is the namesake of the town of Taupō , which sits on a bay in the lake's northeastern shore. With a surface area of 616 km (238 sq mi), it is the largest lake by surface area in New Zealand , and

50-540: A correlation, to within a few years, of a year in which the sky was red over Rome and China . The eruption devastated much of the North Island and further expanded the lake. The area was uninhabited by humans at the time of the eruption, as New Zealand was not settled by Māori until about 1280. Possible climatic effects of the eruption would have been concentrated on the Southern Hemisphere due to

75-558: A food for the trout. A community of sponges and associated invertebrates live around the underwater geothermal vents. Tourism is a major component of Taupō's commercial sector. The busiest time for the industry is the high summer season around Christmas and New Year. The lake area has a temperate climate. Daily maximum temperatures recorded for Taupō range from an average of 23.3 °C in January and February to 11.2 °C in July, while

100-477: A minimum flow of 50 m/s (1,800 cu ft/s) in the Waikato River. The resource consent allows the level of the lake to be varied between 355.85 and 357.25 metres (1,167.5 and 1,172.1 ft) above sea level. Lake Taupō is in a caldera created mainly by a supervolcanic eruption which occurred approximately 25,600 years ago. According to geological records, the volcano has erupted 29 times in

125-583: A permanent crater lake about 100 m (330 ft) in diameter at an elevation of 6,390 m (20,965 ft) on its eastern side. This is most likely the highest lake of any kind in the world. Due to their unstable environments, some crater lakes exist only intermittently. Caldera lakes in contrast can be quite large and long-lasting. For instance, Lake Toba ( Indonesia ) formed after its eruption around 75,000 years ago. At around 100 kilometres (62 mi) by 30 kilometres (19 mi) in extent and 505 metres (1,657 ft) deep at its deepest point, Lake Toba

150-430: Is a feature of Lake Taupō , in the central North Island of New Zealand . The reef is named after Horomātangi (Horo-matangi), the tāniwha or water monster of the lake, who is said to reside in a cave adjacent to the nearby Motutaiko Island to the south. The name Horomatangi Reefs perhaps better reflects its complex inner and outer structure with the shallow reefs separated by very deep areas, so tends to be used in

175-416: Is reached between the rates of incoming and outgoing water. Sources of water loss singly or together may include evaporation , subsurface seepage, and, in places, surface leakage or overflow when the lake level reaches the lowest point on its rim. At such a saddle location, the upper portion of the lake is contained only by its adjacent natural volcanic dam ; continued leakage through or surface outflow across

200-562: Is the largest crater lake in the world. While many crater lakes are picturesque, they can also be deadly. Gas discharges from Lake Nyos in Cameroon suffocated 1,800 people in 1986, and crater lakes such as Mount Ruapehu 's (New Zealand) often contribute to destructive lahars . Certain bodies of water, although their formation is directly related to volcanic activity, are not usually referred to as crater lakes, including: Horomatangi Reef The Horomatangi Reef or reefs

225-591: The Hatepe eruption , it is believed to have ejected 100 cubic kilometres of material, of which 30 cubic kilometres was ejected in a few minutes. This was one of the most powerful eruptions in the last 5000 years (alongside the Minoan eruption in the 2nd millennium BCE, the Tianchi eruption of Baekdu around 1000 CE and the 1815 eruption of Tambora ), with a Volcanic Explosivity Index rating of 7; and there appears to be

250-598: The Waitahanui River , the Tongariro River , and the Tauranga Taupō River . It is a noted trout fishery with stocks of introduced brown and rainbow trout . The level of the lake is controlled by Mercury Energy , the owner of the eight hydroelectric dams on the Waikato River downstream of Lake Taupō, using gates built in 1940–41. The gates are used to reduce flooding, conserve water and ensure

275-410: The 40.2 km length of the lake is a challenge for open-water swimmers. In 2020, Michael Wells from Darwin, Australia, was the first to breaststroke across the lake. On the north-west side of Lake Taupō on the cliffs of Mine Bay, there are Māori rock carvings created in the late 1970s by Matahi Whakataka-Brightwell and John Randall. Carved in the likeness of Ngātoro-i-rangi , a navigator who guided

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300-517: The Te Arawa waka. Ngāti Tūwharetoa owns the bed of the lake and its tributaries. They grant the public free access for recreational use. Lake Taupō previously housed a Ngāti Tūwharetoa village known as Te Rapa near the springs of Maunga Kākaramea . It was covered in a landslide on 7 May 1846 which killed 60 people, including the iwi's chief Mananui Te Heuheu Tūkino II . Volcanic crater lake Lakes in calderas fill large craters formed by

325-519: The Tūwharetoa and Te Arawa tribes to the Taupō area over a thousand years ago according to Māori legend . The 10-metre-high carving is intended to protect Lake Taupō from volcanic activities underneath. The cliff has become a popular tourist destination with hundreds of boats and yachts visiting the spot yearly. Lake Taupō is a taonga (treasure or something special to the person) of Ngāti Tūwharetoa from

350-402: The caldera. The caldera later filled with water to form Lake Taupō, eventually overflowing to cause a huge outburst flood . Several later eruptions occurred over the millennia before the most recent major eruption, which was traditionally dated as about 181 CE from Greenland ice-core records. Tree ring data from two studies suggests a later date of 232 CE ± 5 and this is now accepted. Known as

375-413: The collapse of a volcano during an eruption. Lakes in maars fill medium-sized craters where an eruption deposited debris around a vent. Crater lakes form as the created depression, within the crater rim , is filled by water. The water may come from precipitation , groundwater circulation (often hydrothermal fluids in the case of volcanic craters) or melted ice . Its level rises until an equilibrium

400-545: The dam can erode its included material, thus lowering lake level until a new equilibrium of water flow, erosion, and rock resistance is established. If the volcanic dam portion erodes rapidly or fails catastrophically, the occurrence produces a breakout or outburst flood. With changes in environmental conditions over time, the occurrence of such floods is common to all natural dam types. These lakes may become soda lakes , many of which are associated with active tectonic and volcanic zones. A well-known crater lake, which bears

425-701: The geological literature, while the term reef tends to be used geographically. The reefs are at a high heat-output geothermal hot spot area within the Taupō Volcano . This is related to rhyolitic lava domes extruded after explosive volcanism. The explosive eruptions include the VEI 7 Hatepe eruption of 232 ± 10 CE that ejected over 120 km (29 cu mi) of material (also known as Horomatangi Reef Unit Y eruption) and its linear line of eruption centres, as well as its own namesake Horomatangi, Unit S VEI 6 eruption of about 1460 BCE. Accordingly

450-400: The lake include northern kōura or crayfish ( Paranephrops planifrons ) and kōkopu or whitebait ( Galaxias species). The lake is noted for stocks of brown trout ( Salmo trutta ) and rainbow trout ( Oncorhynchus mykiss ), introduced from Europe and California respectively in the late nineteenth century. There has also been a subsequent introduction of smelt ( Retropinnidae species) as

475-515: The last 30,000 years. It has ejected mostly rhyolitic lava , although Mount Tauhara formed from dacitic lava. Taupō has been active for 300,000 years with a very large event known as the Oruanui eruption occurring approximately 25,600 years ago. It was the world's largest known eruption over the past 70,000 years, ejecting 1170 cubic kilometres of material and causing several hundred square kilometres of surrounding land to collapse and form

500-631: The nighttime minimum temperatures range from 11.6 °C in February down to 2.2 °C in July. Rain falls in all seasons but is greatest in winter and spring, from June to December. Taupō hosts the Lake Taupo Cycle Challenge , a cycling tour around the lake which can take anywhere between four and ten hours. Skydiving is a popular local sport and tourist attraction. Taupō also hosts the ANZCO Ironman event. Crossing

525-492: The reef is perhaps best regarded as a complex volcano within the caldera of another complex volcano. There is one area of 500 m (1,600 ft) diameter dropping to a depth of over 164 m (538 ft) below mean lake level. Recent periods of volcanic unrest of the Taupō Volcano have been associated with earthquake swarms centred in the area of the Horomatangi Reef. From February to October 2022 during

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550-613: The same name as the geological feature, is Crater Lake in Oregon . It is located in the caldera of Mount Mazama . It is the deepest lake in the United States with a depth of 594 m (1,949 ft). Crater Lake is fed solely by falling rain and snow, with no inflow or outflow at the surface, and hence is one of the clearest lakes in the world. The highest volcano in the world, 6,893-m (22,615-ft) Ojos del Salado in Chile , has

575-529: The second largest freshwater lake by surface area in geopolitical Oceania after Lake Murray in Papua New Guinea . Motutaiko Island lies in the southeastern area of the lake. Lake Taupō has a perimeter of approximately 193 km (120 mi) and a maximum depth of 186 m (610 ft). It is drained by the Waikato River (New Zealand's longest river), and its main tributaries are

600-575: The site of occurrence of certain extremophile micro-organisms, that are capable of surviving in extremely hot environments. The volcano is considered active and is monitored by GNS Science. Much of the watershed of Lake Taupō is a beech and podocarp forest with associate understory ferns being Blechnum filiforme , Asplenium flaccidum , Doodia media , Hymenophyllum demissum , Microsorum pustulatum and Dendroconche scandens , and some prominent associate shrubs being Olearia rani and Alseuosmia quercifolia . Native faunal species in

625-623: The southerly position of Lake Taupō. Taupō's last known eruption occurred around 30 years later, with lava dome extrusion forming the Horomatangi Reefs , but that eruption was much smaller than the Hatepe eruption. Underwater hydrothermal activity continues near the Horomatangi vent, and nearby geothermal fields with associated hot springs are found north and south of the lake, for example at Rotokawa and Tūrangi . These springs are

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