The
Auckland volcanic field is a generally
monogenetic volcanic fieldA monogenetic volcanic field is a volcanic field of small, scattered volcanic vents. These volcanic fields, containing numerous monogenetic volcanoes, are noted for having only one short eruptive event at each volcano, as opposed to regular volcanoes that have several eruptions from the same vent...
in the
North IslandThe North Island is one of the two main islands of New Zealand, separated from the South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
of
New ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses , and numerous smaller islands, most notably Stewart Island/Rakiura and the Chatham Islands. The indigenous Māori named New Zealand Aotearoa, commonly translated as The Land of the Long White Cloud...
.
BasaltBasalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey.On Earth, most...
ic in nature, it underlies much of the
metropolitan areaA metropolitan area is a large population center consisting of a large metropolis and its adjacent zone of influence, or of more than one closely adjoining neighboring central cities and their zone of influence...
of
AucklandThe Auckland metropolitan area , in the North Island of New Zealand, is the largest and most populous urban area in the country with a population approaching 1.4 million residents, percent of the country's population. Demographic trends indicate that it will continue to grow faster than the rest...
. The field's many vents have produced a diverse array of explosion craters,
scoriaScoria is a textural term for macrovesicular volcanic rock. It is commonly, but not exclusively, basaltic or andesitic in composition. Scoria is light as a result of numerous macroscopic ellipsoidal vesicles, but most scoria has a specific gravity greater than 1, and sinks in water. The...
cones, and
lavaLava is molten rock expelled by a volcano during eruption. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at temperatures from 700 °C to 1,200 °C...
flows. Currently dormant, the field is likely to erupt again within the next "hundreds to thousands of years" (based on past events), a very short timeframe in geologic terms.
Volcanoes
The first vents erupted at the
DomainThe Auckland Domain is Auckland's oldest park, and at 75 hectares one of the largest in the city. Located in the central suburb of Grafton, the park lies mostly within the crater of the Pukekawa volcano.....
,
Albert ParkAlbert Park is a scenic park in central Auckland, bounded by Wellesley Street East, Princes Street, Bowen Avenue and Kitchener Street. From the entrance at the corner of Bowen Ave and Kitchener St, sealed footpaths climb steeply through native trees to the large flat area at the summit, where...
and
St HeliersSaint Heliers is a residential Auckland City suburb, located at the eastern end of the city, where the Tamaki estuary divides it from Manukau City.This area was originally called Glen Orchard after Lieutenant-Colonel William Taylor's farm...
between 60,000 and 140,000 years ago. Since then approximately 50 vents have erupted. Each eruptive vent has generally only had a geologically short period of activity. One exception is
Panmure BasinPanmure Basin is a volcanic crater or maar within the Auckland Volcanic Field in New Zealand. It is located to the south of Panmure town centre....
, where drilling has discovered a younger scoria cone buried under sediment within the larger and much older crater.
The most recent eruption (about 600 years ago and within historical memory of the local
MāoriThe Māori are the indigenous Polynesian people of New Zealand . The group probably arrived in southwestern Polynesia in several waves at some time before 1300...
iwis) was of Rangitoto, an island
shield volcanoA shield volcano is a large volcano with shallow-sloping sides. Shield volcanoes are formed from fluid lava that can travel long distances across slight inclines, resulting in their relatively flat, broad profile...
just east of the city, erupting 2.3 cubic kilometres of lava. The eruptions have tended to become bigger over time, with Rangitoto making up almost 60% of the field's entire volume of erupted material. All of the volcanoes are relatively small, most being less than 150 meters in height.
Lava flows
The field has produced voluminous lava flows, which cover much of the Auckland isthmus. One of the longest runs from
Three KingsThree Kings refers to both a suburb of Auckland, New Zealand, and the three-peaked volcano that it is named after. Three Kings should not be confused with the Three Kings Islands, located off the northern tip of New Zealand's North Island....
northward, almost crossing the
Waitemata HarbourThe Waitemata Harbour is the main access by sea to Auckland, New Zealand. For this reason it is often referred to as Auckland Harbour, despite the fact that it is only one of two harbours surrounding the city, and is crossed by the Auckland Harbour Bridge. The Waitemata forms the north and east...
to form
Meola ReefThe Meola Reef, or Te Tokaroa Reef in Māori is a lava flow forming a reef peninsula across part of Auckland's Waitemata Harbour, New Zealand. It was formed 20,000 years ago from the final portion of a 10 kilometer long lava flow that originated from the distant Three Kings volcano...
. More than 50
lava tubeLava tubes are natural conduits through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption. They can be actively draining lava from a source, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like...
s and other lava caves have been discovered, including the 290 metre long Wiri Lava Cave.
Usage
Several of the volcanic cones were occupied by substantial
MāoriThe Māori are the indigenous Polynesian people of New Zealand . The group probably arrived in southwestern Polynesia in several waves at some time before 1300...
paThe word pā traditionally refers to a Māori village or settlement. In contemporary Western usage, it has come to refer to a Māori hillfort from the 17th - 19th centuries, that was fortified with palisades and earthworks such as defensive terraces. Prior to the 1960s, any Māori settlement,...
before European settlement, and many terraces and other archeological remnants are still visible. Many of the cones have been levelled or strongly altered - in small part due to the historical
MāoriThe Māori are the indigenous Polynesian people of New Zealand . The group probably arrived in southwestern Polynesia in several waves at some time before 1300...
use, but mostly through relatively recent quarrying of construction materials (especially
scoriaScoria is a textural term for macrovesicular volcanic rock. It is commonly, but not exclusively, basaltic or andesitic in composition. Scoria is light as a result of numerous macroscopic ellipsoidal vesicles, but most scoria has a specific gravity greater than 1, and sinks in water. The...
). However several of the remaining volcanoes are now preserved as landmarks and parks. The cones are also protected by a 1915 law, the Reserves and Other Lands Disposal and Public Bodies Empowering Act 1915, which was passed due to early concern that the distinctive landscape was being eroded, especially by quarrying. While often ignored until the late 20th century, it has amongst other things minimised severe changes to Mount Roskill proposed by
Transit New ZealandTransit New Zealand was, from 1989 to 2008, the New Zealand Crown entity responsible for operating and planning the New Zealand State Highway network...
for the Southwestern Motorway.
In March 2007, New Zealand submitted the volcanic field, with several specifically named features, as a
World Heritage SiteA UNESCO World Heritage Site is a site that is on the list that is maintained by the international World Heritage Programme administered by the UNESCO World Heritage Committee, composed of 21 state parties which are elected by their General Assembly for a four-year term.A World Heritage Site is a...
candidate based on its unique combination of natural and cultural features. At that time, only 2% of more than 800 World Heritage Sites worldwide were in this "mixed" category.
Dangers
Since the field is not extinct, new volcanic events may occur at any time, though the usual period between events averages between hundreds and thousands of years. However, the effects of such an event, especially a full-scale eruption, would be substantial - ranging from
earthquakeAn earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph...
s, lava bombs,
ash fallVolcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
s, venting
volcanic gasVolcanic gases include a variety of substances given off by active volcanoes. These include gases trapped in cavities in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating directly from lava or indirectly through ground water heated by volcanic action.The sources...
to lava flows. These effects might continue for several months and cause substantial destruction and disruption. These might range from burial of substantial tracts of residential or commercial property to mid-to-long-term closures of major parts of the country's infrastructure, such as the Port of Auckland, the
State Highway networkThe New Zealand State Highway network is the major national highway network in New Zealand. Just under 100 roads in both the North and South Islands are State Highways...
or the Auckland Airport.
Various operative structures, plans and systems have been set up to prepare responses to renewed volcanic activity within the urban areas, mainly coordinated in the 'Auckland Volcanic Field Contingency Plan' of the
Auckland Regional CouncilThe Auckland Regional Council is the regional council of the Auckland Region. Its current chairman is Mike Lee, together with 12 other Councillors...
, which provides a framework for interaction of
civil defenseCivil defense, civil defence or civil protection is an effort to prepare non combatant's for military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...
and emergency services during an eruption. Auckland also has a Seismic Monitoring Network comprising six
seismometerSeismometers are instruments that measure and record motions of the ground, including those of seismic waves generated by earthquakes, nuclear explosions, and other seismic sources...
s (including one 250 m deep at Riverhead) and three repeaters within the
Auckland RegionThe Auckland Region is one of the sixteen regions of New Zealand, named for the city of Auckland, New Zealand's largest. It is the most populous region of New Zealand, as well as being the most prosperous in economic terms.-Geography:...
) that will pick up the small
tremorAn earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph...
s likely preceding any such volcanic activity. These tremors are likely to give some hours to some days of warning about an impending eruption and its approximate location.
List of volcanoes
The volcanoes within the field include:
- Albert Park
Albert Park is a scenic park in central Auckland, bounded by Wellesley Street East, Princes Street, Bowen Avenue and Kitchener Street. From the entrance at the corner of Bowen Ave and Kitchener St, sealed footpaths climb steeply through native trees to the large flat area at the summit, where...
- Ash Hill
- Browns Island
Browns Island or Motukorea is a small New Zealand island, in the Hauraki Gulf north of Musick Point, one of the best preserved volcanoes in the Auckland Volcanic Field. It erupted 8,000 to 12,000 years ago, exhibiting a range of activity including ash, lava and scoria eruptions...
(Motukorea)
- Crater Hill
- Green Hill
- Hampton Park
- Hopua
- Kohuora
- Lake Pupuke
Lake Pupuke is a heart-shaped freshwater lake occupying a volcanic explosion crater between the suburbs of Takapuna and Milford on the North Shore of Auckland, New Zealand. Separated from the sea by less than 200 m at one point, it has a circumference of about 4.5 km and reaches...
- Little Rangitoto
- Mangere Lagoon
Mangere Lagoon is a lagoon in the Manukau Harbour, New Zealand. It occupies a volcanic crater or maar which is part of the Auckland volcanic field...
- Mangere Mountain
Mangere Mountain is one of the largest volcanic cones in the Auckland Volcanic Field, with a peak 107 metres above sea level, and was the site of a major pā. Many of the pā's earthworks are still very evident...
- Manurewa
Manurewa is the southernmost major suburb of Manukau City, one of the four cities that make up the metropolitan area of Auckland in the North Island of New Zealand...
- Matakarua
- Maungataketake
- McLennan Hills
- Mount Albert
Mount Albert is a volcanic peak and suburban area in the city of Auckland, New Zealand.The peak, in parkland at the southern end of the suburb, is 135 metres in height, and is one of the many extinct cones which dot the city of Auckland, all of which are part of the Auckland Volcanic Field...
(Owairaka)
- Mount Cambria
- Mount Eden
Mount Eden is the name of a cinder cone and surrounding suburb in Auckland City, New Zealand, situated five kilometres south of the city centre. The mountain is the highest natural point in the whole of Auckland...
(Maungawhau)
- Mount Hobson
Mount Hobson is a volcano cone of the Auckland Volcanic Field in Auckland, New Zealand.Located in the Remuera suburb, to the east of the Newmarket commercial suburb, it has been extensively modified by human use, first by Māori use as a Pā and later by being used as a quarry, pasture land and...
(Remuwera)
- Mount Richmond
- Mount Roskill
- Mount Saint John
- Mount Smart
Mount Smart is a suburb and a former volcanic peak in Auckland, New Zealand. The cone was quarried over a period of 100 years and is now the site of Mount Smart Stadium....
- Mount Victoria
Mount Victoria is the highest volcano on Auckland's North Shore but rises to a mere 87 m. It erupted some 20,000 years ago, and its lava flows now line much of Devonport's waterfront...
- Mount Wellington
Mount Wellington is a peak and a suburb in Auckland City, New Zealand-The peak:Mount Wellington is a 137 metre volcanic peak located in the Auckland volcanic field of Auckland, New Zealand. It is the youngest onshore volcano of the Auckland volcanic field, having been formed by an eruption around...
(Maungarei)
- North Head
North Head is a volcanic headland within North Shore City, New Zealand, in the suburb of Devonport at the east end of the Waitemata Harbour ....
(Maungauika)
- One Tree Hill
One Tree Hill is a 182 metre volcanic peak located in Auckland, New Zealand. It is an important memorial place for both Māori and other New Zealanders...
(Maungakiekie)
- Onepoto
Onepoto may refer to:* Onepoto , a feature near Northcote in Auckland, New Zealand* Onepoto, New Zealand, a suburb of Porirua, New Zealand* Onepoto Bridge, a bridge in Auckland, New Zealand...
- Orakei Basin
- Otara Hill
- Otuataua
- Panmure Basin
Panmure Basin is a volcanic crater or maar within the Auckland Volcanic Field in New Zealand. It is located to the south of Panmure town centre....
- Pigeon Mountain
- Pukaki Lagoon
- Pukeiti
- Pukekawa
The Auckland Domain is Auckland's oldest park, and at 75 hectares one of the largest in the city. Located in the central suburb of Grafton, the park lies mostly within the crater of the Pukekawa volcano.....
(Auckland Domain volcano)
- Pukekiwiriki
- Puketutu Island
Puketutu Island is a volcanic island in the Manukau Harbour, New Zealand, and is part of the Auckland volcanic field. In the 1950s, its scoria cones were heavily quarried for fill to extend Auckland Airport nearby...
- Rangitoto Island
Rangitoto Island is a volcanic island in the Hauraki Gulf near Auckland, New Zealand. The 5.5 km wide island is an iconic and widely visible landmark of Auckland with its distinctive symmetrical shield volcano cone rising 260 metres high over the Hauraki Gulf...
- Robertson Hill (Sturges Park)
- Saint Heliers (Glover Park) - see Achilles Point
Achilles Point is a rocky point on the headland at the eastern end of the small sandy beach named Ladies Bay, Auckland, New Zealand. The name 'Te Pane o Horoiwi' can also sometimes refer to the whole headland between St Heliers and Tamaki River estuary...
- Styaks Swamp
- Tank Farm
Tank Farm is the name of a volcanic explosion crater in North Shore City, New Zealand, near the approaches to the Auckland Harbour Bridge....
(also known as 'Tuff Crater Lagoon')
- Taylor's Hill
- Te Pouhawaiki
- Three Kings
Three Kings refers to both a suburb of Auckland, New Zealand, and the three-peaked volcano that it is named after. Three Kings should not be confused with the Three Kings Islands, located off the northern tip of New Zealand's North Island....
- Waitomokia
External links
- NZ Institute of Geological and Nuclear Sciences Auckland Volcano page
- Auckland Regional Council - The Volcanoes of Auckland
- University of Auckland's Geology of Auckland page (with interactive maps, requiring Apple
Apple Inc. is an American multinational corporation that designs and manufactures consumer electronics and computer software products. The company's best-known hardware products include Macintosh computers, the iPod and the iPhone...
QuickTimeQuickTime is a multimedia framework developed by Apple Inc., capable of handling various formats of digital video, media clips, sound, text, animation, music, and interactive panoramic images. It is available for Mac OS classic , Mac OS X and Microsoft Windows operating systems...
).
Gallery
Rangitoto Island
Lake Pupuke and Takapuna
Devonport Volcanoes
Mt Eden
Mt Hobson and Mt StJohn
One Tree Hill
Three Kings, Mt Roskill and Mt Albert
Mt Wellington
Mangere
Basins