Auckland Volcanic Field
Encyclopedia
Monogenetic volcanic field
A 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 Island
North Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
of New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. Basalt
Basalt
Basalt 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...
ic in nature, it underlies much of the metropolitan area
Metropolitan area
The term metropolitan area refers to a region consisting of a densely populated urban core and its less-populated surrounding territories, sharing industry, infrastructure, and housing. A metropolitan area usually encompasses multiple jurisdictions and municipalities: neighborhoods, townships,...
of Auckland
Auckland
The Auckland metropolitan area , in the North Island of New Zealand, is the largest and most populous urban area in the country with residents, percent of the country's population. Auckland also has the largest Polynesian population of any city in the world...
.
The field's many vents have produced a diverse array of explosion craters, scoria
Scoria
Scoria is a volcanic rock containing many holes or vesicles. It is most generally dark in color , and basaltic or andesitic in composition. Scoria is relatively low in mass as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity...
cones, and lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. 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...
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 vent erupted at Onepoto VolcanoOnepoto (volcanic crater)
Onepoto is the name of a volcanic explosion crater in North Shore City, New Zealand. It is a part of the Auckland volcanic field.Located near the approaches to the Auckland Harbour Bridge, it was created by a series of eruptions approximately 250,000 years ago...
248,000 ± 28,000 years ago. Since then approximately 50 vents have erupted. Each eruptive vent has generally only had a geologically short period of activity.
The most recent eruption (about 600 years ago and within historical memory of the local Māori iwi) was of Rangitoto, an island shield volcano
Shield volcano
A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their large size and low profile, resembling a warrior's shield. This is caused by the highly fluid lava they erupt, which travels farther than lava erupted from more explosive volcanoes...
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.
Lake Pupuke
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. The heart shape is a result of its formation by the linking of two circular craters - a larger one forming most of the lake...
, on the North Shore near Takapuna
Takapuna
Takapuna is a central, coastal suburb of North Shore City, located in the northern North Island of New Zealand, at the beginning of a south-east-facing peninsula forming the northern side of the Waitemata Harbour...
, is a volcanic explosion crater. A few similar craters such as Orakei Basin are open to the sea.
Lava flows
The field has produced voluminous lava flows, which cover much of the Auckland isthmus. One of the longest runs from Mt Saint JohnMount Saint John, New Zealand
Mount Saint John is one of the volcanic scoria cones in the Auckland Volcanic Field. It has a peak 126 metres above sea level and a crater around 150 m wide. It was the site of a pā, and has retained Māori earthworks from that era such as kumara pits and terracing...
northward, almost crossing the Waitemata Harbour
Waitemata Harbour
The quite famous 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...
to form Meola Reef
Meola Reef
The 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 tube
Lava tube
Lava 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
Wiri Lava Cave
Wiri lava cave is one of Auckland's longest lava caves at around 290 metres. It is part of Matukutūruru volcano, in the Auckland volcanic field. Features such as lava stalactites mean it is considered of international importance...
.
The second longest individual cave in the Auckland field is the cave of a Thousand Pressups to the east of One Tree Hill.It is 270m long.
Human context
Usage
Many of the volcanic cones were occupied by substantial Māori paPa (Maori)
The word pā can refer to any Māori village or settlement, but in traditional use it referred to hillforts fortified with palisades and defensive terraces and also to fortified villages. They first came into being about 1450. They are located mainly in the North Island north of lake Taupo...
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 Māori use, but mostly through relatively recent quarrying of construction materials (especially scoria
Scoria
Scoria is a volcanic rock containing many holes or vesicles. It is most generally dark in color , and basaltic or andesitic in composition. Scoria is relatively low in mass as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity...
). 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 Zealand
Transit New Zealand
Transit 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 Site
World Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...
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 pyroclastic surges, earthquakeEarthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
s, lava bombs, ash fall
Volcanic ash
Volcanic 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 gas
Volcanic gas
|250px|thumb|right|Image of the [[rhyolitic]] [[lava dome]] of [[Chaitén Volcano]] during its 2008-2010 eruption.Volcanic gases include a variety of substances given off by active volcanoes...
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 network
New Zealand State Highway network
The 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. One possibility is that more than one volcano may erupt in Auckland at one time. There is strong evidence that five erupted within a span of 50 years or less, approximately 32,000 years ago.
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 Council
Auckland Regional Council
The Auckland Regional Council was the regional council of the Auckland Region. Its predecessor the Auckland Regional Authority was formed in 1963 and became the ARC in 1989...
, which provides a framework for interaction of civil defense
Civil defense
Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from 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 seismometer
Seismometer
Seismometers are instruments that measure motions of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources...
s (including one 250 m deep at Riverhead) and three repeaters within the Auckland Region
Auckland Region
The Auckland Region was one of the sixteen regions of New Zealand, named for the city of Auckland, the country's largest urban area. With one third of the nation's residents, it was by far the biggest population and economy of any region of New Zealand, but the second-smallest land area.On 1...
) that will pick up the small tremor
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
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.
Auckland Museum
Auckland War Memorial Museum
The Auckland War Memorial Museum is one of New Zealand's most important museums and war memorials. Its collections concentrate on New Zealand history , natural history, as well as military history.The museum is also one of the most iconic Auckland buildings, constructed in the neo-classicist...
, itself built on the crater rim of Pukekawa
Auckland Domain
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 contains all of the explosion crater and most of the surrounding tuff ring of the Pukekawa volcano....
, has an exhibition on the Auckland volcanic field, including the "Puia Street multi-sensory visitor experience" which simulates a grandstand view of an eruption in Auckland.
List of volcanoes
- Albert Park VolcanoAlbert Park, AucklandAlbert 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 Crater, 32,000 yrs old
- Auckland Domain/PukekawaAuckland 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 contains all of the explosion crater and most of the surrounding tuff ring of the Pukekawa volcano....
- Boggust Park CraterBoggust Park CraterBoggust Park Crater is a volcano in Auckland, New Zealand. Located in the Favona area of the Mangere suburb, it is one of Auckland city's older volcanoes. It was first recognised as a volcano in 2011...
- Cemetery CraterCemetery CraterCemetery Crater is one of the volcanoes in the Auckland Volcanic Field. It is an explosion crater roughly wide, located east of Crater Hill. Hard to see even in early aerial photos due to its shallowness, it is now covered by housing.Hayward, B.W., Kenny, J.A., and Grenfell, H.R. . ". Geoscience...
- Crater HillCrater HillCrater Hill is one of the volcanoes of the Auckland Volcanic Field. It consists of an explosion crater about 600m wide, partly filled with water....
, 32,000 yrs old - Grafton VolcanoGrafton VolcanoGrafton Volcano is a buried volcano in New Zealand's Auckland volcanic field that underlies much of the Auckland suburb of Grafton. First recognised in 2010, it includes the Outhwaite Park scoria cone that was first mapped by Hochstetter and inferred by later geologists to be a late phase vent of...
- Green Mount/MatanginuiGreen Hill, New ZealandGreen Hill is one of the volcanoes in the Auckland Volcanic Field. It's scoria cone had a peak 78 metres above sea level , and had a grove of Karaka trees. The hill was the site of a pā. It was quarried from 1870 onwards, and has been mostly quarried away. The site is now Greenmount landfill...
- Hampton ParkHampton Park, New ZealandHampton Park is one of the volcanoes in the Auckland Volcanic Field. A small scoria cone reaching 35 m above sea level, with a shallow crater around 50 m wide, which has been modified by quarrying. The scoria cone sits in the centre of a much larger explosion crater - the eastern arc of the...
- KohuoraKohuoraKohuora is one of the volcanoes in the Auckland Volcanic Field. An explosion crater around 600 m wide, 30 m deep and with an irregular V-shape indicating it was formed by at least three explosion crater vents...
, 32,000 yrs old - Lake Pupuke/Pupuke MoanaLake PupukeLake 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. The heart shape is a result of its formation by the linking of two circular craters - a larger one forming most of the lake...
, ~200,000 yrs old - Little Rangitoto/MaungarahiriLittle RangitotoLittle Rangitoto is one of the volcanoes in the Auckland Volcanic Field. This scoria cone had a peak 75 m above sea level before it was mostly quarried away. The quarry site is now Little Rangitoto Reserve, having been partly filled with refuse in the 1950s...
- Mangere LagoonMangere LagoonMangere 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/Te Pane a MataahoMangere MountainMangere Mountain is one of the largest volcanic cones in the Auckland Volcanic Field, with a peak 106 metres above sea level, and was the site of a major pā. Many of the pā's earthworks are still very evident. It offers spectacular panoramic views of Auckland.The mountain features two large craters...
- Matukutureia/McLaughlin Mountain
- Maungataketake/Elletts MountainMaungataketakeMaungataketake is one of the volcanoes in the Auckland Volcanic Field. It had a 76 m high scoria cone, beside a 100 m wide crater, before they were quarried away. It was the site of a pā...
- McLennan Hills/Te Apunga o TainuiMcLennan HillsMcLennan Hills is one of the volcanoes in the Auckland Volcanic Field. It was a group of cratered scoria mounds up to 45 m high, before it was quarried away. A 1940 aerial photo shows a crater around 100 m wide, one around 50 m wide, and 2 or 3 smaller craters...
, ~40,000 yrs old
- Motukorea/Browns IslandBrowns Island, AucklandBrowns 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. The age of eruption is currently unknown. Due to centuries of cultivation, little native bush remains except on the north-eastern...
- Mount Albert/Te Ahi ka roa a Raka/OwairakaMount Albert, New ZealandMount Albert is a volcanic peak and suburban area in the city of Auckland, New Zealand. The suburb was Auckland's second, after Remuera, and was mostly settled by well-off families in the late 1800s and early 1900s...
- Mount Cambria/TakararoMount CambriaMount Cambria is one of the volcanoes in the Auckland Volcanic Field. Located north-east of Mt Victoria, it's 30m scoria cone was quarried away. The site is now Cambria Reserve...
- Mount Eden/MaungawhauMount EdenMount 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...
, 28,000 yrs old - Mount Hobson/OhinerangiMount Hobson, AucklandMount Hobson is a 143 m high volcanic cone in 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...
(Remuwera) - Mount Richmond/OtahuhuMount RichmondMount Richmond is one of the volcanoes of the Auckland Volcanic Field. A group of scoria mounds up to 50 m high, it has two 50 m wide craters...
, 32,000 yrs old - Mount Robertson/Sturges ParkRobertson HillRobertson Hill is one of the volcanoes in the Auckland Volcanic Field. It's scoria cone reaches 78 metres above sea level . The scoria cone crater was reshaped into an oval sports field with terraced seating...
- Mount Roskill/Puketapapa
- Mount Saint John/Te KopukeMount Saint John, New ZealandMount Saint John is one of the volcanic scoria cones in the Auckland Volcanic Field. It has a peak 126 metres above sea level and a crater around 150 m wide. It was the site of a pā, and has retained Māori earthworks from that era such as kumara pits and terracing...
- Mount Smart/RarotongaMount SmartMount Smart is one of the volcanoes in the Auckland Volcanic Field. Quarrying removed almost all of the scoria cone, which was 87 m high . It was the site of a pā and was known as Rarotonga...
- Mount Victoria/TakarungaMount Victoria, AucklandMount Victoria is the highest volcano on Auckland's North Shore, rising to 87 m. Its age is currently unknown. Its lava flows now line much of Devonport's waterfront...
- Mount Wellington/MaungareiMount Wellington, Auckland-The volcano: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 10,000 years ago...
, 10,000 yrs old - North Head/MaungauikaNorth Head, New ZealandNorth Head is a volcanic cone forming a headland within North Shore City, New Zealand, in the suburb of Devonport at the east end of the Waitemata Harbour ....
- One Tree Hill/MaungakiekieOne Tree Hill, New ZealandOne 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...
- Onepoto Basin/Te Kopua o MatakerepoOnepoto (volcanic crater)Onepoto is the name of a volcanic explosion crater in North Shore City, New Zealand. It is a part of the Auckland volcanic field.Located near the approaches to the Auckland Harbour Bridge, it was created by a series of eruptions approximately 250,000 years ago...
, ~250,000 yrs old - Orakei BasinOrakei BasinOrakei Basin is one of the volcanoes in the Auckland Volcanic Field. It has an explosion crater around 700 m wide, with a surrounding tuff ring. After eruption about 85,000 yrs ago, it became a freshwater lake that had an overflow stream in the vicinity of present Orakei Rd bridge...
, ~85,000 yrs old - Otara Hill/Te Puke o Taramainuku/Smales HillOtara HillOtara Hill is one of the volcanoes in the Auckland Volcanic Field. Its scoria cone reached 89 m above sea level before it was quarried away. The hill was the site of a pā...
- OtuatauaOtuatauaOtuataua is one of the volcanoes in the Auckland Volcanic Field. The scoria cone reached 64 m above sea level but was mostly quarried away, leaving the base of the cone with a large depression in it...
- Panmure Basin/Te Kopua Kai a HikuPanmure BasinThe Panmure Basin, also sometimes known as the Panmure Lagoon, is a tidal estuary within a volcanic crater or maar in New Zealand's Auckland Volcanic Field. It is located to the south of Panmure town centre....
- Pigeon Mountain/O Huiarangi
- Puhinui CratersPuhinui CratersThe Puhinui Craters are located in Auckland's Puhinui Reserve and are part of New Zealand's Auckland Volcanic Field. They were first recognised as volcanic craters in 2011. A cluster of three small maar craters like these is unique in the Auckland Volcanic Field. Their ages are unknown but most...
- Pukaki Lagoon/Te Pukaki Tapu o PoutukekaPukaki LagoonPukaki Lagoon is one of the volcanoes in the Auckland Volcanic Field. It has a 600 m wide explosion crater, with a surrounding tuff ring. After eruption about 65,000 yrs ago the crater filled with freshwater and became a lake. It was breached by the sea as sea-level rise after the end of the...
, ~65,000 yrs old - Pukeiti/Puketapapakanga a Hape
- Pukewairiki/Highbrook Park
- Puketutu Island/Te Motu a HiaroaPuketutu IslandPuketutu Island is a volcanic island in the Manukau Harbour, New Zealand, and is part of the Auckland volcanic field. European settlers called it Weekes' Island, but this was eventually removed again in favour of the historical Māori name....
, 32,000 yrs old - Purchas Hill/Te TauomaPurchas HillPurchas Hill is one of the volcanoes in the Auckland Volcanic Field. It was a twin-cratered scoria cone around 50 m high, located north of Mount Wellington, before it was quarried away. The scoria cone sat in the middle of its large explosion crater with surrounding tuff ring...
, 10,000 yrs old - Rangitoto, 600 yrs old
- Saint Heliers/Whakamuhu/Glover Park - see Achilles PointAchilles PointAchilles 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 SwampStyaks SwampStyaks Swamp is one of the volcanoes in the Auckland Volcanic Field. An explosion crater around 200 m wide with a surrounding tuff ring. Located north of Green Hill. The crater once contained a swamp but is now covered by industrial development.-References:...
- Tank Farm/Te Kopua o MatakamokamoTank FarmTank 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 - Taylors Hill/Taurere, 32,000 yrs old
- Te Hopua a Rangi/Gloucester Park
- Te Pou Hawaiki
- Three Kings/Te Tatua a RiukiutaThree Kings, New ZealandThree 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.- Suburb :...
, 28,500 yrs old - Waitomokia/Moerangi/Mt GabrielWaitomokiaWaitomokia is one of the volcanoes in the Auckland Volcanic Field. Its wide tuff crater contained three small scoria cones up to high, one with a crater, which were quarried away.-References:...
- Wiri Mountain/Te Manurewa o TamapahoreMatukutururuMatukutūruru is one of the volcanoes in the Auckland Volcanic Field. It had a scoria cone reaching 80 metres above sea level , which was quarried away. The lava flows created 290m long Wiri Lava Cave...
, 32,000 yrs old
External links
- NZ Institute of Geological and Nuclear Sciences Auckland Volcano page
- Auckland Museum pages about Auckland volcanic field
- Auckland Regional Council - The Volcanoes of Auckland
- University of Auckland's Geology of Auckland page (with interactive maps, requiring AppleApple ComputerApple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
QuickTimeQuickTimeQuickTime is an extensible proprietary multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. The classic version of QuickTime is available for Windows XP and later, as well as Mac OS X Leopard and...
).