Auckland volcanic field
| Auckland Volcanic Field | |
|---|---|
 Map of the field drawn by Hochstetter in 1859 and published in English in 1864 | |
| Highest point | |
| Elevation | 260 m (850 ft) |
| Coordinates | 36°52′37″S 174°45′50″E / 36.877°S 174.764°ECoordinates: 36°52′37″S 174°45′50″E / 36.877°S 174.764°E |
| 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 an area of monogenetic volcanoes covered by much of the metropolitan area of Auckland, New Zealand's largest city, located in the North Island. The approximately 53 volcanoes[1] in the field have produced a diverse array of maars (explosion craters), tuff rings, scoria cones, and lava flows. With the exception of Rangitoto, no volcano has erupted more than once, but eruptions lasted for various periods ranging from a few weeks to several years.[2] Rangitoto erupted twice; the first eruption occurred about 600 years ago, followed by a second eruption approximately 50 years later.[3] The field is fuelled entirely by basaltic magma, unlike the explosive subduction-driven volcanism in the central North Island, such as at Mount Ruapehu and Lake Taupō.[4] The field is currently dormant, but could become active again.[5]
Features[]
The field ranges from Lake Pupuke and Rangitoto Island in the north to Matukutururu (Wiri Mountain) in the south, and from Mount Albert in the west to Pigeon Mountain in the east.
The first vent erupted at Pupuke 193,200 ± 2,800 years ago.[6] The most recent eruption (about 600 years ago[7] and within historical memory of the local Māori) was of Rangitoto, an island shield volcano just east of the city, erupting 0.7 cubic kilometres of lava. The last volcano to erupt was much bigger than all others, with Rangitoto making up 41 per cent of the field's entire volume of erupted material. [8] The field's volcanoes are relatively small, with most less than 150 metres (490 ft) in height.
Lake Pupuke, on the North Shore near Takapuna, is a volcanic explosion crater. A few similar craters such as Orakei Basin are open to the sea.
The field has produced voluminous lava flows that cover much of the Auckland isthmus. One of the longest runs from Mt Saint John northward, almost crossing the Waitematā Harbour to form Meola Reef.[9] More than 50 lava tubes and other lava caves have been discovered, including the 290-metre (950 ft)-long Wiri Lava Cave.[10] The second-longest individual cave in the Auckland field, some 270 metres (890 ft) in total length, is the Cave of a Thousand Press-ups to the east of Maungakiekie/One Tree Hill.[11] Two impressive depressions caused by lava cave collapses are the Puka Street Grotto and the nearby Hochstetter Pond, also known as Grotto Street Pond, in Onehunga.[12][13]
For most of the 200,000 years that the field has been erupting, the planet has been in glacial periods (ice ages) where sea levels were much lower due to water being locked up as ice, and the Waitemata and Manukau Harbours were dry land. All the volcanoes probably erupted on land except for Rangitoto, which erupted during the current interglacial (warmer) period.[14]
Human context[]
Mythology[]
Tāmaki Māori myths describe the creation of the volcanic field as a creation of Mataaho (the guardian of the earth's secrets) and his brother Rūaumoko (the god of earthquakes and volcanoes), made as punishment against a tribe of patupaiarehe, supernatural beings living in the Waitākere Ranges, who used deadly magic from the earth to defeat a war party of patupaiarehe from the Hunua Ranges.[15][16] In some traditions, the fire goddess Mahuika creates the volcanic field as a way to warm Mataaho, after his wife leaves and takes his clothing.[17][18] Because of their close association to Mataaho, the volcanic features can be collectively referred to as Nga Maunga a Mataaho ("The Mountains of Mataaho"),[15] or Ngā Huinga-a-Mataaho ("the gathered volcanoes of Mataaho").[18] Many of the volcanic features of Māngere can be referred to as Nga Tapuwae a Mataoho ("The Sacred Footprints of Mataoho"), including Māngere Lagoon, Waitomokia, Crater Hill, Kohuora, Pukaki Lagoon and Robertson Hill.[17][19] Many of the Māori language names of volcanic features in the field refer to Mataaho by name, including Te Pane o Mataaho (Māngere Mountain), Te Tapuwae a Mataoho (Robertson Hill) and Te Kapua Kai o Mataoho (the crater of Maungawhau / Mount Eden).
Usage[]
Many of the volcanic cones were occupied by substantial Māori pā (fortifications) before European settlement, and many terraces and other archeological remnants are still visible.[20] 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). However several of the remaining volcanoes are now preserved as landmarks and parks.[7] The warmer northern sides of the mountains were also popular among early European settlers for housing.[20] In the 1880s, Takarunga / Mount Victoria and Maungauika / North Head were developed as military installations due to fears of a Russian invasion.[20] 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 for the Southwestern Motorway.[21]
In March 2007, New Zealand submitted the volcanic field, with several specifically named features, as a World Heritage Site candidate based on its unique combination of natural and cultural features.[7] At that time, only 2 per cent of more than 800 World Heritage Sites worldwide were in this "mixed" category.
For most of Auckland's European history, the mountains have been administered variously by the New Zealand Crown, the Auckland Council (or its former bodies including the Auckland City Council and Manukau City Council) or the Department of Conservation.[20] After the was passed, ownership of 14 major mountains across the region was transferred to the Tūpuna Maunga o Tāmaki Makaurau Authority, a collective of thirteen iwi and hapū with traditional ties to Tāmaki Makaurau (the Auckland region).[20][22] The authority administers the mountains for the common benefit of Tāmaki Māori and other residents of Auckland.[20]
Dangers[]
Since the field is not extinct, new volcanic events may occur at any time, though the usual period between events is, on average, somewhere between hundreds to thousands of years. However, the effects of such an event—especially a full-scale eruption—would be substantial, ranging from pyroclastic surges to earthquakes,[23] lava bombs, ash falls, and the venting volcanic gas, as well as lava flows. These effects might continue for several months, potentially causing substantial destruction and disruption, ranging from the burial of substantial tracts of residential or commercial property, to the mid-to-long-term closures of major parts of the country's infrastructure such as the Port of Auckland, the State Highway network, or the Auckland Airport.[5] It is possible that several volcanoes could erupt simultaneously. There is strong evidence that eight erupted within a span of 3000 years or so, between 31,000 and 28,000 years ago.
Various operative structures, plans and systems have been set up to prepare responses to volcanic activity within the urban areas, mainly coordinated in the Auckland Volcanic Field Contingency Plan[24] of the Auckland Regional Council, which provides a framework for interaction of civil defence and emergency services during an eruption. Auckland also has a seismic monitoring network comprising six seismometers—including one 250 metres (820 ft) deep at Riverhead—and three repeaters within the region that will detect the small tremors likely to precede any volcanic activity.[25] This is likely to give between a few hours and several days' warning of an impending eruption, and its approximate location.[23]
Auckland War Memorial Museum, itself built on the crater rim of Pukekawa, has an exhibition on the field, including the "Puia Street multi-sensory visitor experience", which simulates a grandstand view of an eruption in Auckland.[26]
In 2013, scientists said new studies showed Rangitoto had been much more active in the past than previously thought, suggesting it had been active on and off for around 1000 years before the final eruptions around 550 years ago.[27] Civil Defence officials said the discovery did not make living in Auckland any more dangerous, but did change their view of how an evacuation might proceed.[28]
List of volcanoes[]
The volcanoes within the field are:[2][29][30]
See also[]
- List of volcanoes in New Zealand
- Volcanism in New Zealand
- Stratigraphy of New Zealand
References[]
- ^ a b c d Hayward, Bruce W.; Kenny, Jill A.; Grenfell, Hugh R. (2011). "More volcanoes recognised in Auckland Volcanic Field" (PDF). Geoscience Society of New Zealand Newsletter (5): 11–16. Retrieved 19 April 2013.[permanent dead link]
- ^ a b Hayward, Bruce W.; Murdoch, Graeme; Maitland, Gordon (2011). Volcanoes of Auckland: The Essential Guide. Auckland University Press. ISBN 978-1-86940-479-6.
- ^ Needham, A.J.; Lindsay, J.M.; Smith, I.E.M.; Augustinus, P.; Shane, P.A. (April 2011). "Sequential eruption of alkaline and sub-alkaline magmas from a small monogenetic volcano in the Auckland Volcanic Field, New Zealand". Journal of Volcanology and Geothermal Research. 201 (1–4): 126–142. doi:10.1016/j.jvolgeores.2010.07.017.
- ^ Ian E.M. Smith and Sharon R. Allen. Auckland volcanic field geology. Volcanic Hazards Working Group, Civil Defence Scientific Advisory Committee. Retrieved 30 March 2013. Also published in print as Volcanic hazards at the Auckland volcanic field. 1993.
- ^ a b Beca Carter Hollings & Ferner (2002). Contingency Plan for the Auckland Volcanic Field, Auckland Regional Council Technical Publication 165. Accessed 12 May 2008.
- ^ Leonard, G. S., Calvert, A. T., Hopkins, J. L., Wilson, C. J., Smid, E. R., Lindsay, J. M., & Champion, D. E. (2017). High-precision 40Ar/39Ar dating of Quaternary basalts from Auckland Volcanic Field, New Zealand, with implications for eruption rates and paleomagnetic correlations. Journal of Volcanology and Geothermal Research [1] 343:60-74
- ^ a b c Auckland Volcanic Fields submission (from the UNESCO World Heritage Centre, 30 March 2007. Accessed 4 May 2007)
- ^ Kereszturi, G., Németh, K., Cronin, S. J., Agustín-Flores, J., Smith, I. E., & Lindsay, J. (2013). A model for calculating eruptive volumes for monogenetic volcanoes—Implication for the Quaternary Auckland Volcanic Field, New Zealand. Journal of Volcanology and Geothermal Research, [2] 266:16-33.
- ^ Hayward, Murdoch, Maitland (2011). pp. 134–135.
- ^ David Lomas (Winter 2006). "Cave new world". Heritage New Zealand. Accessed 4 May 2007.
- ^ Kermode, Les (March 1994). "New Zealand lava caves worth preserving for their geologic and geomorphic features" (PDF). Geoscience Reports of Shizuoka University. 20: 15–24. Archived from the original (PDF) on 3 August 2016. Retrieved 6 December 2011.
- ^ Hayward, Murdoch, Maitland (2011). pp. 17–18.
- ^ "Geology". The Onehunga Grotto. 9 May 2008. Retrieved 25 April 2013.
- ^ Hayward, Murdoch, Maitland (2011). pp. 2–3.
- ^ a b "Mataaho". maori.org.nz. Archived from the original on 1 December 2020. Retrieved 12 September 2021.
- ^ Pegman, David M (August 2007). "The Volcanoes of Auckland" (PDF). Manukau City Council. Mangere Mountain Education Centre. Archived from the original (PDF) on 1 December 2020. Retrieved 6 October 2021.
- ^ a b "The History of Our Marae". Makaurau Marae. Retrieved 1 September 2021.
- ^ a b Taonui, Rāwiri (10 February 2015). "Tāmaki tribes". Te Ara: The Encyclopedia of New Zealand. Ministry for Culture and Heritage. Retrieved 15 September 2016.
- ^ Graham, George (1979). "George Graham's Maori Place Names of Auckland". Records of the Auckland Institute and Museum. 16: 11-39.
- ^ a b c d e f Tūpuna Maunga o Tāmaki Makaurau Authority (23 June 2016). "Integrated Management Plan" (PDF). Auckland Council. Retrieved 6 October 2021.
- ^ "The volcanic hills are being destroyed..." – City of Fire, insert magazine in The New Zealand Herald, 15 February 2008
- ^ New Zealand Government (31 July 2014). "Ngā Mana Whenua o Tāmaki Makaurau Collective Redress Act 2014". Retrieved 13 September 2021.
- ^ a b "When the earth starts to shake". City of Fire, insert magazine in The New Zealand Herald, 15 February 2008.
- ^ "Auckland Volcanic Field Contingency Plan" (PDF). Archived from the original (pdf) on 23 September 2015.
- ^ New recorder boosts earthquake, volcano warnings, The New Zealand Herald, NZPA, 11 May 2008. Accessed 12 May 2008.
- ^ "Volcanoes". Auckland War Memorial Museum. Retrieved 28 September 2017.
- ^ "Rangitoto more active than thought – study". 3 News NZ. 11 April 2013.
- ^ "Officials downplay volcano danger". Newshub. 12 April 2013.
- ^ Lindsay, J.M.; Leonard, G.S.; Smid, E.R.; Hayward, B.W. (December 2011). "Age of the Auckland Volcanic Field: a review of existing data". New Zealand Journal of Geology and Geophysics. 54 (4): 379–401. doi:10.1080/00288306.2011.595805. S2CID 129707270.
- ^ Hayward, B.W. (2019). Volcanoes of Auckland. A Field Guide. Auckland University Press. p. 334. ISBN 978-1-86940-901-2.
- ^ Hopkins, Jenni L.; Smid, Elaine R.; Eccles, Jennifer D.; Hayes, Josh L.; Hayward, Bruce W.; McGee, Lucy E.; van Wijk, Kasper; Wilson, Thomas M.; Cronin, Shane J.; Leonard, Graham S.; Lindsay, Jan M.; Németh, Karoly; Smith, Ian E. M. (3 July 2021). "Auckland Volcanic Field magmatism, volcanism, and hazard: a review". New Zealand Journal of Geology and Geophysics. 64 (2–3): 213–234. doi:10.1080/00288306.2020.1736102.
- ^ Searle, E. J. (May 1962). "The volcanoes of Auckland city". New Zealand Journal of Geology and Geophysics. 5 (2): 193–227. doi:10.1080/00288306.1962.10423108.
- ^ Mountain, Māngere. "Mangere Mountain History Formation | Mangere Mountain". Māngere Mountain. Retrieved 28 April 2019.
Further reading[]
- Lava and Strata: A guide to the volcanoes and rock formations of Auckland. Homer, Lloyd; Moore, Phil & Kermode, Les; Landscape Publications and the Institute of Geological and Nuclear Sciences, 2000. ISBN 0-908800-02-9.
- "Probabilistic assessment of future vent locations and eruption styles for the Auckland Volcanic Field, New Zealand". Magill, Christina R; McAneney, K.J.; Proceedings of the 2003, Portsmouth, UK, 7–12 September 2003.
- Volcanic risk ranking for Auckland, New Zealand. I: Methodology and hazard investigation. Magill, Christina R.; Blong, Russell; Bulletin of Volcanology, Volume 67, Issue 4, April 2005, Pages 331 – 339, DOI 10.1007/s00445-004-0374-6, accessed 2006-07-14.
- City of Volcanoes: A geology of Auckland. Searle, Ernest J.; revised by Mayhill, R.D.; Longman Paul, 1981. First published 1964. ISBN 0-582-71784-1.
- "Facies analysis of pyroclastic deposits within basaltic tuff-rings of the Auckland volcanic field, New Zealand (abstract)". Sharon R. Allen, Vivienne F. Bryner, Ian E. M. Smith, Peter F. Ballance, New Zealand Journal of Geology and Geophysics, 1996, Vol. 39: 309–327.
- Volcanoes of Auckland: A Field Guide. Hayward, B.W.; Auckland University Press, 2019, 335 pp. ISBN 0-582-71784-1.
External links[]
 |
Wikimedia Commons has media related to Auckland volcanic field. |
- Volcanic hazards, Auckland Council
- "Auckland field". Global Volcanism Program. Smithsonian Institution.
- "Volcanoes". Auckland War Memorial Museum. Retrieved 28 September 2017.
- Geology: Rocks and minerals, School of Geography, Geology and Environmental Science, University of Auckland (with interactive maps, requiring Apple QuickTime).
- Auckland volcanic field
- Potentially active volcanoes
- Monogenetic volcanic fields
- Geography of Auckland
- Landforms of the Auckland Region
- Mountains of the Auckland Region