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Auckland volcanic field facts for kids

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Auckland Volcanic Field
Map of the Auckland Volcanic Field from 1859
Map of the field drawn by Hochstetter in 1859 and published in English in 1864
Highest point
Elevation 260 m (850 ft)
Geology
Age of rock Pleistocene and Holocene
Mountain type Volcanic Field
Type of rock Basalt
Last eruption c. 1400 CE

The Auckland volcanic field is a special area in Auckland, New Zealand. It is home to many different volcanoes. Auckland is the largest city in New Zealand, located on the North Island.

This area has about 53 volcanoes. Each volcano has erupted only once. They have created various landforms like big holes (called maars), flat rings of ash (tuff rings), rocky hills (scoria cones), and rivers of hardened rock (lava flows).

Even though each volcano erupts only once, an eruption can last for weeks or even years. The volcanoes here are fed by a type of molten rock called basaltic magma. This is different from the powerful, explosive volcanoes in the central North Island, like Mount Ruapehu and Lake Taupō. The Auckland volcanic field is currently quiet, or dormant. But it could become active again in the future.

What Makes the Auckland Volcanic Field Special?

The volcanic field stretches across a large area. It goes from Lake Pupuke and Rangitoto Island in the north. It reaches Matukutururu (Wiri Mountain) in the south. From west to east, it spans from Mount Albert to Pigeon Mountain.

The first volcano to erupt in this field was at Pupuke. This happened about 193,200 years ago. The most recent eruption was about 600 years ago. This was Rangitoto, an island volcano just east of the city. It was a huge eruption, sending out 0.7 cubic kilometres of lava. Rangitoto is much bigger than the other volcanoes. It makes up 41% of all the material that has erupted from the field. Most of the volcanoes in the field are quite small, usually less than 150 metres (490 feet) tall.

Lake Pupuke, near Takapuna, is a large hole made by a volcanic explosion. Other similar craters, like Orakei Basin, are now open to the sea.

The volcanoes have also created many large lava flows. These flows cover much of the Auckland area. One of the longest flows goes from Mt Saint John northwards. It almost crosses the Waitematā Harbour to form Meola Reef. More than 50 lava tubes (underground tunnels made by flowing lava) and other lava caves have been found. One example is the 290-metre (950-foot) long Wiri Lava Cave. Another long cave is the Cave of a Thousand Press-ups, near Maungakiekie/One Tree Hill. There are also impressive dips in the ground where lava caves have collapsed. These include the Puka Street Grotto and Hochstetter Pond in Onehunga.

For most of the last 200,000 years, the Earth has been in ice ages. During these times, sea levels were much lower because a lot of water was frozen in ice. The Waitemata and Manukau Harbours were dry land. Most volcanoes likely erupted on land. Rangitoto is an exception, as it erupted during the current warmer period between ice ages.

Volcanoes and People

TerracingonOneTreeHill
Terraces carved by Māori into the slopes of One Tree Hill

How People Have Used the Volcanoes

Many of the volcanic hills were once home to large Māori . These were fortified villages. You can still see terraces and other signs of these old settlements today. Many of the cones have been flattened or changed a lot. This was partly due to Māori use, but mostly because of recent quarrying. Quarrying is when rocks, especially scoria, are dug out for building materials.

However, several remaining volcanoes are now protected. They are important landmarks and parks. A law from 1915 helps protect these cones. This law was passed because people were worried that the unique landscape was being destroyed. This law has helped prevent big changes to places like Mount Roskill.

In 2007, New Zealand suggested that the Auckland volcanic field become a World Heritage Site. This is because it has a special mix of natural and cultural features. At that time, only 2% of World Heritage Sites were in this "mixed" category.

What Are the Dangers?

The volcanic field is not extinct, meaning it could erupt again. New volcanic events could happen at any time. Usually, there are hundreds or thousands of years between eruptions. However, if a big eruption happened, the effects would be serious. These could include fast-moving clouds of hot gas and ash (pyroclastic surges), earthquakes, flying rocks (lava bombs), ash falling from the sky, and volcanic gases. There could also be lava flows.

These effects might last for several months. They could cause a lot of damage and disruption. Homes and businesses could be buried. Important parts of the country's transport system, like the Port of Auckland, the State Highway network, or the Auckland Airport, might have to close. It's even possible that several volcanoes could erupt at the same time. There is evidence that eight volcanoes erupted within a 3,000-year period, between 31,000 and 28,000 years ago.

To prepare for volcanic activity, special plans and systems are in place. The Auckland Regional Council has an 'Auckland Volcanic Field Contingency Plan'. This plan helps civil defence and emergency services work together during an eruption. Auckland also has a network of six seismometers. These devices detect small tremors that usually happen before a volcanic eruption. This system could give people a few hours to several days of warning before an eruption, and help pinpoint its location.

The Auckland War Memorial Museum, which is built on the edge of the Pukekawa crater, has an exhibition about the volcanic field. It includes a "Puia Street multi-sensory visitor experience" that makes you feel like you're watching an eruption in Auckland.

In 2013, scientists found that Rangitoto was much more active in the past than they first thought. It was active on and off for about 1,000 years before its final eruptions around 550 years ago. Civil Defence officials said this discovery doesn't make living in Auckland more dangerous. However, it does change how they might plan an evacuation if needed.

List of Volcanoes

The volcanoes within the field are:

Volcanoes Age (thousand years) Height Location (Coordinates) Refs Images
Albert Park Volcano 145 Unclear 36°51′03″S 174°46′03″E / 36.8507°S 174.7675°E / -36.8507; 174.7675
Ash Hill 30.5 30 metres (98 ft) 37°00′10″S 174°52′03″E / 37.002754°S 174.867545°E / -37.002754; 174.867545
Boggust Park Crater 130 5 metres (16 ft) 36°57′19″S 174°48′49″E / 36.955413°S 174.813552°E / -36.955413; 174.813552
Cemetery Crater Unknown 33 metres (108 ft) 36°59′23″S 174°50′28″E / 36.989828°S 174.841082°E / -36.989828; 174.841082
Crater Hill 30.5 36°59′12″S 174°49′38″E / 36.986546°S 174.827135°E / -36.986546; 174.827135
Grafton Volcano 100 36°51′30″S 174°45′49″E / 36.858440°S 174.763624°E / -36.858440; 174.763624
Hampton Park Unknown 35 metres (115 ft) 36°57′03″S 174°53′44″E / 36.950925°S 174.89544°E / -36.950925; 174.89544
Kohuora 30.5 36°58′43″S 174°50′34″E / 36.97873°S 174.842691°E / -36.97873; 174.842691
Mangere Lagoon 50 36°57′25″S 174°46′39″E / 36.95702°S 174.77763°E / -36.95702; 174.77763
Matanginui/Green Mount 20 78 metres (256 ft) 36°56′24″S 174°53′54″E / 36.939911°S 174.898267°E / -36.939911; 174.898267
Matukutureia/McLaughlins Mountain 50 73 metres (240 ft) 37°00′49″S 174°50′46″E / 37.013511°S 174.845974°E / -37.013511; 174.845974
Maungakiekie/One Tree Hill 60 182 metres (597 ft) 36°54′0″S 174°46′59″E / 36.90000°S 174.78306°E / -36.90000; 174.78306
One Tree Hill, Auckland
One Tree Hill and its obelisk
Maungarahiri/Little Rangitoto 24.5 75 metres (246 ft) 36°52′31″S 174°48′35″E / 36.875407°S 174.809636°E / -36.875407; 174.809636
Maungarei/Mount Wellington 10 135 metres (443 ft) 36°53′35″S 174°50′47.6″E / 36.89306°S 174.846556°E / -36.89306; 174.846556
Maungataketake/Elletts Mountain 90 76 metres (249 ft) 36°59′41″S 174°44′51″E / 36.994635°S 174.747548°E / -36.994635; 174.747548
Maungauika/North Head 90 50 metres (160 ft) 36°49′40″S 174°48′43″E / 36.827751°S 174.81205°E / -36.827751; 174.81205
Maungawhau/Mount Eden 28 196 metres (643 ft) 36°52′37″S 174°45′50″E / 36.877°S 174.764°E / -36.877; 174.764
Mount Eden Crater Hollow Auckland
Crater of Maungawhau / Mount Eden
Motukorea/Browns Island 24 68 metres (223 ft) 36°49′50″S 174°53′41″E / 36.8306°S 174.8948°E / -36.8306; 174.8948
Mount Robertson/Sturges Park 24 78 metres (256 ft) 36°56′55″S 174°50′30″E / 36.948477°S 174.841726°E / -36.948477; 174.841726
Ōhinerau / Mount Hobson 34 143 metres (469 ft) 36°52′40″S 174°47′10″E / 36.877814°S 174.786156°E / -36.877814; 174.786156
Ohuiarangi/Pigeon Mountain 24.5 55 metres (180 ft) 36°53′20″S 174°54′11″E / 36.888846°S 174.903116°E / -36.888846; 174.903116
Orakei Basin 120 Sea level 36°52′02″S 174°48′47″E / 36.867124°S 174.81308°E / -36.867124; 174.81308
Otahuhu/Mount Richmond 30 50 metres (160 ft) 36°55′57″S 174°50′22″E / 36.932562°S 174.839451°E / -36.932562; 174.839451
Ōtuataua 15 64 metres (210 ft) 36°59′10″S 174°45′15″E / 36.98611°S 174.75417°E / -36.98611; 174.75417
Ōwairaka / Mount Albert 120 135 metres (443 ft) 36°53′26″S 174°43′12″E / 36.890475°S 174.720097°E / -36.890475; 174.720097
Puhinui Craters 50 22 metres (72 ft) 37°00′53″S 174°49′59″E / 37.01465°S 174.83296°E / -37.01465; 174.83296
Pukaki Lagoon 65 Sea Level 36°58′59″S 174°48′37″E / 36.982998°S 174.810226°E / -36.982998; 174.810226
Pukeiti 15 30 metres (98 ft) 36°59′02″S 174°45′26″E / 36.983756°S 174.757183°E / -36.983756; 174.757183
Pukekawa/Auckland Domain 100 36°51′33″S 174°46′33″E / 36.859158°S 174.775808°E / -36.859158; 174.775808
Puketāpapa / Mount Roskill 105 110 metres (360 ft) 36°55′S 174°44′E / 36.917°S 174.733°E / -36.917; 174.733
Pukewairiki 130+ 30 metres (98 ft) 36°56′39″S 174°51′57″E / 36.944078°S 174.865887°E / -36.944078; 174.865887
Pupuke 190 −57 metres (−187 ft) 36°46′48″S 174°45′58″E / 36.780115°S 174.766184°E / -36.780115; 174.766184
Rangitoto Island 0.6 260 metres (850 ft) 36°47′12″S 174°51′36″E / 36.786742°S 174.860115°E / -36.786742; 174.860115
Rangitoto from Achilles Point
Rangitoto Island on the horizon
Rarotonga / Mount Smart 20 87 metres (285 ft) (quarried) 36°55′6″S 174°48′45″E / 36.91833°S 174.81250°E / -36.91833; 174.81250
Styaks Swamp 20 36°56′10″S 174°54′01″E / 36.936138°S 174.900155°E / -36.936138; 174.900155
Takaroro / Mount Cambria 40 30 metres (98 ft) (quarried) 36°49′28″S 174°48′07″E / 36.824444°S 174.801933°E / -36.824444; 174.801933
Takarunga / Mount Victoria 35 87 metres (285 ft) 36°49′36″S 174°47′56″E / 36.8266°S 174.7990°E / -36.8266; 174.7990
Taurere / Taylors Hill 30 56 metres (184 ft) 36°51′51″S 174°52′12″E / 36.864223°S 174.869943°E / -36.864223; 174.869943
Te Apunga-o-Tainui / McLennan Hills 41 45 metres (148 ft) (quarried) 36°55′45″S 174°50′47″E / 36.929208°S 174.846468°E / -36.929208; 174.846468
Te Hopua-a-Rangi / Gloucester Park 20+ Sea level (reclaimed) 36°55′46″S 174°47′05″E / 36.9295°S 174.784734°E / -36.9295; 174.784734
Te Kopua Kai-a-Hiku / Panmure Basin 25 Sea level 36°54′18″S 174°50′58″E / 36.90495°S 174.849343°E / -36.90495; 174.849343
Te Kopua-o-Matakamokamo / Tank Farm 180 36°48′07″S 174°45′12″E / 36.8020°S 174.7533°E / -36.8020; 174.7533
Onepoto 185 36°48′29″S 174°45′03″E / 36.80818°S 174.75085°E / -36.80818; 174.75085
Te Kōpuke / Mount Saint John 75 126 metres (413 ft) 36°53′00″S 174°46′49″E / 36.883431°S 174.780196°E / -36.883431; 174.780196
Te Motu-a-Hiaroa/Puketutu 30 65 metres (213 ft) 36°57′55″S 174°44′50″E / 36.965186°S 174.747248°E / -36.965186; 174.747248
Te Pane-o-Mataaho/Māngere Mountain 50 106 metres (348 ft) 36°56′59″S 174°46′59″E / 36.9496°S 174.7831°E / -36.9496; 174.7831
Te Pou Hawaiki 28 Quarried 36°52′57″S 174°46′00″E / 36.88247°S 174.766726°E / -36.88247; 174.766726
Te Puke ō Tara / Otara Hill Unknown 89 metres (292 ft) (quarried) 36°56′50″S 174°53′54″E / 36.947105°S 174.898363°E / -36.947105; 174.898363
Te Tātua-a-Riukiuta / Three Kings 28.5 133 metres (436 ft) 36°54′11″S 174°45′17″E / 36.902926°S 174.754651°E / -36.902926; 174.754651
Te Tauoma / Purchas Hill 10 50 metres (160 ft) (quarried) 36°53′14″S 174°50′51″E / 36.887138°S 174.847476°E / -36.887138; 174.847476
Waitomokia / Mt Gabriel 20.3 20 metres (66 ft) (quarried) 36°58′37″S 174°46′13″E / 36.976981°S 174.770336°E / -36.976981; 174.770336
Whakamuhu/Saint Heliers/Glover Park – see Achilles Point 160 Sea level 36°50′36″S 174°51′50″E / 36.843390°S 174.863800°E / -36.843390; 174.863800
Wiri Mountain / Matukutūruru 30 80 metres (260 ft) (quarried) 37°00′26″S 174°51′30″E / 37.007334°S 174.858441°E / -37.007334; 174.858441

See also

Kids robot.svg In Spanish: Campo volcánico de Auckland para niños

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