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Taupō Volcanic Zone

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Vorlage:Citations missing

Mount Ngauruhoe
Lady Knox Geyser, Wai-O-Tapu geothermal area
Satellite photo of Lake Taupo
Whakaari/White Island
Craters of the Moon geothermal area
Composite satellite image of Mount Ruapehu

The Taupo Volcanic Zone is a highly active volcanic area in the North Island of New Zealand. It is named after Lake Taupo, the flooded caldera of the largest volcano in the zone.

Activity

There are numerous volcanic vents and geothermal fields in the zone, with Mount Ruapehu, Mount Ngauruhoe and White Island erupting most frequently. The zone's largest eruption since the arrival of Europeans was that of Mount Tarawera in 1886, which killed over 100 people. Early Māori would also have been affected by the much larger Kaharoa eruption from Tarawera around 1300 CE.[1]

The last major eruption from Lake Taupo, the Hatepe eruption, occurred in 181 CE. It is believed to have first emptied the lake then followed that feat with a pyroclastic flow that covered about 20,000 square kilometres of land with volcanic ash. A total of 120 km³ of material is believed to have been ejected, and over 30 km³ of material is estimated to have been ejected in just a few minutes. The date of this activity is known since the ash expulsion was sufficiently large to turn the sky red over Rome and China (as documented in Hou Han Shu).

Taupo erupted an estimated 1,170 km³ of material in its Oruanui eruption 26,500 years ago. This was Earth's most recent eruption reaching VEI-8, the highest level on the Volcanic Explosivity Index.

The Rotorua caldera has been dormant longer, producing its most recent giant eruption about 240,000 years ago, although lava dome extrusion has occurred within the last 25,000 years.[2]

Extent and geological context

The Taupo Volcanic Zone is approximately 350 kilometres long by 50 kilometres wide. Mount Ruapehu marks its southwestern end, while the submarine Whakatane volcano (85 kilometres beyond White Island) is considered its northeastern limit.[3]

It forms a southern portion of the active Lau-Havre-Taupo back-arc basin, which lies behind the Kermadec-Tonga subduction zone.[4] Volcanic activity continues to the north-northeast, along the line of the Taupo Volcanic Zone, through several undersea volcanoes (known as Clark, Tangaroa, the Silents and the Rumbles), then shifts eastward to the parallel volcanic arc of the Kermadec Islands and Tonga. Although the back-arc basin continues to propagate to the southwest, with the South Wanganui Basin forming an initial back-arc basin, volcanic activity has not yet begun in this region.[5] The Taupo Volcanic Zone can therefore be seen as the southwestern end of the Pacific Ring of Fire, which marks out the subduction zones around the Pacific Ocean.

South of Kaikoura the plate boundary changes to a transform boundary with oblique continental collision uplifting the Southern Alps in the South Island. A subduction zone reappears southwest of Fiordland, at the southwestern corner of the South Island, although here the subduction is in the opposite direction. Solander Island is an extinct volcano associated with this subduction zone, and the only one that protudes above the sea.

Scientific study

Recent scientific work indicates that the earth's crust below the Taupo Volcanic Zone may be as little as 16 kilometres thick. A film of magma 50 kilometres (30 mi) wide and 160 kilometres (100 mi) long lies 10 kilometres under the surface.[6][7] The geological record indicates that some of the volcanoes in the area erupt infrequently but have large, violent and destructive eruptions when they do. There is also some possible rifting in the Taupo Volcanic Zone.

Volcanoes, lakes and hydrothermal areas

See also List of volcanoes in New Zealand#Taupo Volcanic Zone.

The following Volcanic Centers belong to the Taupo Volcanic Zone:

Rotorua, Okataina, Maroa, Taupo, Tongariro and Mangakino.[8][9]

The Mangakino Volcanic Center is the westernmost and oldest rhyolitic caldera volcano in the Taupo Volcanic Zone.[10] The Waikato River flows from the Mount Ruapehu to the Lake Taupo, about 40 km from the lake it flows West, into the artificial Lake Ohakuri. This lake drowned two thirds of the Orakei Korako (Vorlage Coord: Einbindungsfehler
Bitte verwende Vorlage:Coordinate.Koordinaten fehlen! Hilf mit.) hydrothermal area and then it goes through the Mangakino Volcanic Center, finally heading towards Hamilton (Vorlage Coord: Einbindungsfehler
Bitte verwende Vorlage:Coordinate.Koordinaten fehlen! Hilf mit.).

Other important features of the TVZ include the Whakatane, Ngakuru and Ruapehu grabens.

See also

References

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  1. ↑ David Lowe, Polynesian settlement and impacts of volcanism on early Maori society, pp. 50-55 in Lowe, D.J. (ed), Guidebook for ‘Land and Lakes’ field trip, New Zealand Society of Soil Science Biennial Conference, Rotorua. New Zealand Society of Soil Science, Lincoln.
  2. ↑ http://www.volcano.si.edu/world/volcano.cfm?vnum=0401042A
  3. ↑ Gamble, J. A., I. C. Wright and J. A. Baker: Seafloor geology and petrology in the oceanic to continental transition zone of the Kermadec-Havre-Taupo Volcanic Zone arc system, New Zealand. In: New Zealand Journal of Geology and Geophysics. 36. Jahrgang, 1993, S. 417–435 (rsnz.org).
  4. ↑ L. M. Parson and I. C. Wright: The Lau-Havre-Taupo back-arc basin: A southward-propagating, multi-stage evolution from rifting to spreading. In: Tectonophysics. 263. Jahrgang, 1996, S. 1–22, doi:10.1016/S0040-1951(96)00029-7.
  5. ↑ P. Villamor and K. R. Berryman: Evolution of the southern termination of the Taupo Rift, New Zealand. In: New Zealand Journal of Geology & Geophysics. 49. Jahrgang, 2006, S. 23–37 (org.nz).
  6. ↑ Central North Island sitting on magma film Paul Easton, The Dominion Post, 15 September 2007. Retrieved 2008-03-16
  7. ↑ W. Heise, H.M. Bibby and T.G. Caldwell: Imaging magmatic Processes in the Taupo Volcanic Zone (New Zealand) with Magnetotellurics. In: Geophysical Research Abstracts. 9. Jahrgang, 2007 (cosis.net [PDF]). 01311.
  8. ↑ Cole, J.W., 1990, Structural control and origin of volcanism in the Taupo volcanic zone, New Zealand: Bulletin of Volcanology, v. 52, 445-459.
  9. ↑ [1] New Zealand
  10. ↑ Krippner, Stephen J. P., Briggs, Roger M., Wilson, Colin J. N., Cole, James W.; Petrography and geochemistry of lithic fragments in ignimbrites from the Mangakino Volcanic Centre: implications for the composition of the subvolcanic crust in western Taupo Volcanic Zone, New Zealand; New Zealand Journal of Geology and Geophysics, 1998, Vol. 41: 187-199
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