Mount Tongariro (; ) is a

compound volcano A complex volcano, also called a compound volcano or a volcanic complex, is a mixed landform consisting of related volcanic centers and their associated lava flows and pyroclastic rock. They may form due to changes in eruptive habit or i ...

in the

Taupō Volcanic Zone The Taupō Volcanic Zone (TVZ) is a volcanic area in the North Island of New Zealand that has been active for the past two million years and is still highly active. Mount Ruapehu marks its south-western end and the zone runs north-eastward thro ...

of the North Island of

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. It is located to the southwest of

Lake Taupō Lake Taupō (also spelled Taupo; mi, Taupō-nui-a-Tia or ) is a large crater lake in New Zealand's North Island, located in the caldera of the Taupō Volcano. The lake is the namesake of the town of Taupō, which sits on a bay in the lake's no ...

, and is the northernmost of the three active volcanoes that dominate the landscape of the central North Island.

Geology

Mount Tongariro is part of the Tongariro volcanic centre, which consists of four massifs made of

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predo ...

: Tongariro, Kakaramea-Tihia Massif,

Pihanga Pihanga is a andesitic volcanic peak in the North Island Volcanic Plateau, located to the north of Mount Tongariro, between Tongariro and Lake Taupo. Lake Rotoaira lies to the south-west of Pihanga, and the smaller Lake Rotopounamu is situated ...

, and Ruapehu at the southern end of the

North Island Volcanic Plateau The North Island Volcanic Plateau (often called the Central Plateau and occasionally the Waimarino Plateau) is a volcanic plateau covering much of central North Island of New Zealand with volcanoes, lava plateaus, and crater lakes. It contains ...

. The andesitic eruptions formed Tongariro, a steep stratovolcano, reaching a height of . Tongariro is composed of layers of both

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

and

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 re ...

and the eruptions that built the current stratovolcano commenced about 275,000 years ago. Tongariro consists of at least 12 cones. Ngāuruhoe, 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, the last episode in 1973 to 1975. Emerald Lakes from the summit of Red Crater

Emerald Lakes from the summit of Red Crater

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

fumarole A fumarole (or fumerole) is a vent in the surface of the Earth or other rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

s. There are many explosion craters on the massif; water has filled some of these to form the Blue Lake and the Emerald Lakes. The high altitude and severe alpine climate between March and October cause snowfall in the winter (there are commercial ski-fields at neighbouring Mount Ruapehu) and rain can freeze, causing verglas; in contrast in the mid to late summer, the mountains can be bare apart from remnant patches of snow in south-facing gullies. 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. Dating of

moraines A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice she ...

on western Tongariro show that valley glaciers were present at several times during the last glacial cycle, before melting away at the end of the Last Glacial Maximum approximately 18,000 years ago.

History

Mount Tongariro is in the

Tongariro National Park Tongariro National Park (; ) is the oldest national park in New Zealand,Department of Conservation"Tongariro National Park: Features", retrieved 21 April 2013 located in the central North Island. It has been acknowledged by UNESCO as a World H ...

, New Zealand's first national park and one of the earliest in the world. It was set aside (literally "made sacred") in 1887 by Te Heuheu Tukino IV (Horonuku), paramount chief of the

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the C ...

Ngati Tuwharetoa ''Ngati'' is a 1987 New Zealand feature film directed by Barry Barclay, written by Tama Poata and produced by John O'Shea. Production ''Ngati'' is of historical and cultural significance in New Zealand as it is the first feature film written an ...

iwi Iwi () are the largest social units in New Zealand Māori society. In Māori roughly means "people" or "nation", and is often translated as "tribe", or "a confederation of tribes". The word is both singular and plural in the Māori language, ...

and made a national park in order to preserve its natural beauty. The park also includes the peaks of Ngāuruhoe and Ruapehu, both of which lie to the southwest of Tongariro. The national park is a dual

World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...

for its outstanding natural and intangible cultural values. The

Tongariro Alpine Crossing The Tongariro Alpine Crossing in Tongariro National Park is a tramping track in New Zealand, and is among the most popular day hikes in the country. The Tongariro National Park is a World Heritage site which has the distinction of dual status, ...

hiking route passes between Tongariro and Ngāuruhoe. Mount Tongariro and its surroundings are also one of the several locations which Peter Jackson chose to shoot ''The Lord of the Rings'' film trilogy.

Eruptive history

The oldest recorded volcanism in the area was at 933,000 ± 46,000 years ago at Hauhungatahi, northwest of Ruapehu. There is then a gap in identified materials until a small lava inlier on the western side of Tongariro that has been dated at 512,000 ± 59,000 years ago and is essentially buried by more recent activity. The cone and ring-plain of the complex has multiple eruptive centres aligned with the Taupō volcanic rift and bounded by the

Waihi Waihi is a town in Hauraki District in the North Island of New Zealand, especially notable for its history as a gold mine town. The town is at the foot of the Coromandel Peninsula, close to the western end of the Bay of Plenty. The nearby re ...

and Poutu fault zones. The formation of these began about 304,000 years ago in the Tama lakes area and definitely was established by 230,000 years ago. The eruptive centres extend from the Te Maari craters in the northeast to the Tama Lakes in the southwest and include the more classic cone of Mount Ngāuruhoe which like North Crater, another symmetrical but smaller cone, required the absence of ice after the last ice age to form. Tongariro displays evidence for extensive Quaternary glaciation in the form of moraines and lava-ice interaction textures. However Pukeonake is off this axis, approximately 6 km west of the linear vent zone, but is considered to be a satellite vent. There was an intense period of large explosive eruptions around 11,000 years ago from multiple vents between Tongariro and Ruapehu (the Pahoka-Mangamate sequence).

2012 Te Māri eruptions

After a period of volcanic unrest that had resulted in an increase in alert level on 20 July 2012, at 11:50 pm (NZST,

UTC+12 UTC+12:00 is an identifier for a time offset from UTC of +12:00. As standard time (year-round) ''Principal cities: Petropavlovsk-Kamchatsky, Mata Utu, Majuro, Yaren, Funafuti, South Tarawa on Tarawa'' North Asia *Russia – Kamchatka Time ...

) on 6 August 2012, Mt Tongariro had what was initially believed to be a hydrothermal eruption after this increased activity. The eruption occurred at the Te Māri Craters, which had not had a major ash eruption since 1897 and had been dormant since September 1899. The eruption occurred in a new vent below the Upper Te Māri crater, and sent blocks as large as in size up to from the vent. An ash cloud high deposited ash into the surrounding area, especially to the east of the volcano. The ash cloud travelled in four hours.

NIWA The National Institute of Water and Atmospheric Research or NIWA ( mi, Taihoro Nukurangi), is a Crown Research Institute of New Zealand. Established in 1992, NIWA conducts research across a broad range of disciplines in the environmental scien ...

reported the ash cloud contained about of ash, and that the ash cloud was long and wide 39 minutes after the eruption. Ash and the smell of sulphur was reported in Napier and

Hastings Hastings () is a large seaside town and borough in East Sussex on the south coast of England, east to the county town of Lewes and south east of London. The town gives its name to the Battle of Hastings, which took place to the north-west ...

. The smell of sulphur was also reported in

Wellington Wellington ( mi, Te Whanganui-a-Tara or ) is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the second-largest city in New Zealand by metr ...

Nelson Nelson may refer to: Arts and entertainment * ''Nelson'' (1918 film), a historical film directed by Maurice Elvey * ''Nelson'' (1926 film), a historical film directed by Walter Summers * ''Nelson'' (opera), an opera by Lennox Berkeley to a lib ...

and Blenheim.

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to the east and State Highway 46 to the north of the mountain each received up to of ash cover, and were closed until the following morning due to ash and low visibility. A layer of ash thick settled on farmland east of Mount Tongariro. Particle sizes were between . The airspace within a radius of the mountain was closed after the eruption, but later reopened to

visual The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (th ...

flights only.

Air New Zealand Air New Zealand Limited () is the flag carrier airline of New Zealand. Based in Auckland, the airline operates scheduled passenger flights to 20 domestic and 30 international destinations in 18 countries, primarily around and within the Pacif ...

cancelled some flights in and out of Rotorua,

Taupō Taupō (), sometimes written Taupo, is a town on the north-eastern shore of Lake Taupō, New Zealand's largest lake, in the central North Island. It is the largest urban area of the Taupō District, and the second-largest urban area in the Wa ...

, Gisborne, Napier,

Wanganui Whanganui (; ), also spelled Wanganui, is a city in the Manawatū-Whanganui region of New Zealand. The city is located on the west coast of the North Island at the mouth of the Whanganui River, New Zealand's longest navigable waterway. Whang ...

and

Palmerston North Palmerston North (; mi, Te Papa-i-Oea, known colloquially as Palmy) is a city in the North Island of New Zealand and the seat of the Manawatū-Whanganui region. Located in the eastern Manawatu Plains, the city is near the north bank of the ...

due to the risk of volcanic ash clogging the engines on their aircraft serving those airports. No injuries were reported, and the only significant property damage was to the Department of Conservation's Ketetahi Hut, which is located west of the Te Māri Craters. There was no official evacuation but 24 people living along State Highway 46 fled their homes for fear of being isolated. Mount Tongariro erupted again at 1:20 pm on 21 November, ejecting an ash cloud 4000 metres into the air. Flights in the area were cancelled, as were several the following morning. Geologists had no warning before the eruption, saying it wasn't linked to warnings the week before of elevated activity at nearby Mount Ruapehu.

References

External links

Tongariro National Park
at the Department of Conservation
Tongariro Alpine Crossing
at the Department of Conservation
Tongariro Alpine Crossing photos
at Virtual Oceania {{DEFAULTSORT:Tongariro, Mount Active volcanoes Complex volcanoes Volcanic crater lakes Mountains of Waikato Stratovolcanoes of New Zealand Tongariro Volcanic Centre VEI-5 volcanoes

Mount Tongariro Mount Tongariro (; ) is a compound volcano in the Taupō Volcanic Zone of the North Island of New Zealand. It is located to the southwest of Lake Taupō, and is the northernmost of the three active volcanoes that dominate the landscape of th ...

Ruapehu District Taupō Volcanic Zone Pleistocene stratovolcanoes Holocene stratovolcanoes