Over 75 million years ago the New Zealand landmass split away from Australia. Over millions of years the land has been twisted, folded, faulted and shaped. It has been split open by volcanoes, covered under thick layers of ash, and layered with ocean sediment as the sea has alternately risen and fallen. The results of these ancient forces can be seen all around us. The City of Dunedin is built on an ancient volcano that has been extinct for about 10 million years. The hills of Port Chalmers are formed from a long extinct volcano. Auckland city is built on and around a series of volcanic cones.

This section covers New Zealand volcanoes which have erupted in the last few thousand years. If you think that just means White Island and Ruapehu you are in for a surprise.

Most of the world's volcanoes are located near the boundaries of crustal plates. In New Zealand from White Island to Mount Ruapehu a group of active volcanoes across the North Island marks the zone where the Pacific plate descends into the mantle. The Australian and Pacific plates are constantly moving towards each other at between 40mm to 60mm a year. As surface rocks are carried deeper, they melt in the subsurface heat, forming pockets of molten magma which rise towards the surface.

If the magma is rich in silica it is thick and viscous, and the volcanoes it produces are often highly explosive. Violent volcanic eruptions may create huge craters and produce massive flows of incandescent dust and gases which solidify to form ignimbrite. Such rocks cover much of the central North Island. Some explosive volcanoes have blasted out enough volcanic dust to coat the entire country, even as far away as the Chatham Islands.

If the magma which forms is richer in magnesium and iron it is usually hotter and more fluid, but less explosive. In the North island the lava solidifies to form andesite. Andesitic volcanoes usually erupt both lava and volcanic ash, building classic cone-shaped mountains such as Mount Taranaki (Egmont).

To find out more about New Zealand's recent volcanic past click on the links below. All but one of these links will take you outside the NZMIA site.

You will find lots of information about New Zealand volcanoes on the website of The Institute of Geological and Nuclear Sciences. The information in the paragraphs above and the photographs on this page have been sourced with permission from GNS.
http://www.gns.cri.nz

or go straight to the volcano section at http://www.gns.cri.nz/earthact/volcanoes/index.html

An overview of New Zealand volcanoes and links to other information can be accessed on the GNS site at:
http://www.gns.cri.nz/earthact/volcanoes/nzvolcanoes/nzvolcanoes.html

This is an excellent site which includes current activity statistics for New Zealand volcanoes, what to do in an eruption, information on how GNS monitors volcanic activity. The photo gallery is excellent and very up to date.

On the same site you should also check out the Kids' Jump Station http://www.gns.cri.nz/news/kids/index.html which links to both the GNS site and external sites. You can download White Island wallpaper for your computer or a White Island screensaver.

This site is a must view, and the best site for up to date information about New Zealand volcanoes.

…White Island …

White Island is New Zealand's only active marine volcano. It is uninhabited, and with good reason. About 100 years ago miners lived on the island. They mined the sulphur ejected from the many vents on the island which is essentially the top of a much larger volcano sticking out of the ocean. Frequent earth tremors and billowing acidic clouds would have made working conditions far from pleasant. In 1914 a large landslide during the night killed the 10 men on the island and destroyed buildings and equipment. Rescuers arriving soon after found only the foundations of buildings and some scattered equipment. The men had presumably been washed out to sea.

Today White Island is a tourist attraction. Boats from the Bay of Plenty take visitors on a day trip to view the remains of the sulphur plant, the steaming crater lake, and steaming vents and boiling pools of water. Helicopters from Tauranga, Rotorua and Whakatane land at Crater Bay. Divers know that the thermally heated waters around the island encourage the growth of a huge variety of fish. Anglers regularly visit the area. Although it has been a killer in the past, right now White Island is an important part of the Bay of Plenty tourism industry.

You can find out more about White Island at:
http://volcano.und.nodak.edu/vwdocs/current_volcs/new_zealand/white.html

Details current activity on White Island off the Bay of Plenty coast. Includes recent photos.

The Smithsonian Institute Global Volcanism Program website also has information on White Island. This material is suited to senior students.
http://www.volcano.si.edu/gvp/volcano/region04/newzeal/whiteisl/var.htm

You can find out the current alert status of White Island on the GNS site
http://www.gns.cri.nz/earthact/volcanoes/index.html

The GNS site also includes maps and information about White Island.
http://www.gns.cri.nz/earthact/volcanoes/nzvolcanoes/newwhitei.html

http://www.geo.mtu.edu/volcanoes/new.zealand/ruapehu/images.html

http://www.geo.mtu.edu/volcanoes/new.zealand/ruapehu/media.html

http://www.geo.mtu.edu/volcanoes/new.zealand/ruapehu/satellite.html

These are links to sections of the Michigan Technological University Volcanoes Page.

http://www.geo.mtu.edu/volcanoes/new.zealand/ruapehu/

Also from the MTU Volcanoes Page, this link is a time capsule of the 1996 Ruapehu eruption. It provides a range of information, photos, Quicktime movies and plenty of links to other sites. A lot of the information on this site is taken from transcripts and official reports. Best suited to senior students.

http://volcano.und.nodak.edu/vwdocs/volc_images/img_ruapehu_crater_lake.html

A link to the Volcano World site page on Ruapehu. Includes an excellent photo of the area taken from the Space Shuttle.

The GNS site provides more detail.
http://www.gns.cri.nz/earthact/volcanoes/nzvolcanoes/okatbook.htm

From the Volcano World site
http://volcano.und.nodak.edu/vwdocs/volc_images/img_tarawera.html

…Taranaki (Egmont) …

Geological evidence suggests that Taranaki erupts every 300-350 years. It is thought that it will be the next significant eruption in New Zealand.
The GNS site has detailed information about Taranaki.
http://www.gns.cri.nz/earthact/volcanoes/nzvolcanoes/egmont.htm

The Volcano World site also features Taranaki.
http://volcano.und.nodak.edu/vwdocs/volc_images/img_egmont.html

…Tangiwai …

Tangiwai isn't a volcano. It's the name given to the disaster which resulted in the loss of 151 lives in 1953 as a mudslide caused by activity on Ruapehu washed away a rail bridge on the Tangiwai River.

Read about the Tangiwai rail disaster on the New Zealand History site
http://www.nzhistory.net.nz/Gallery/Tangiwai/Tangiwai1.htm

From the Volcano World site
http://volcano.und.nodak.edu/vwdocs/volc_images/img_tangiwai.html

…Ngauruhoe …

This active andesite volcano is younger than all the others. geologically it is still a baby at just over two thousand years old. Like Taranaki, its classic snow covered shape makes it a favourite with tourists and photographers.
From the Volcano World site
http://volcano.und.nodak.edu/vwdocs/volc_images/img_ngauruhoe.html

…Mayor Island (Tuhua) …

Tuhua is well known for its big game fishing, less well known as a volcano. It is 6300 years since the last big eruption. The island has been isolated from the mainland for at least 15,000 years and is the only caldera of its type close to New Zealand.
See the information on Mayor Island on the GNS site.
http://www.gns.cri.nz/earthact/volcanoes/nzvolcanoes/mayorisland.htm

…Volcanoes of Auckland, part of the GIS in Schools Project …

http://www.arc.govt.nz/volcanic/index.htm
Great resources for Years 7 and above. An excellent Social Studies resource. This site contains information about Maori heritage, effects on agriculture and water resources, likely eruption scenarios and many other topics. If you live in the Auckland region this site will have immediate relevance.

Senior students can access the GNS site for detailed information about Auckland's volcanoes.
http://www.gns.cri.nz/earthact/volcanoes/nzvolcanoes/auckland.htm

Taupo Facts & Figures

• The effects of the Taupo eruption were seen in the sky as far away as Europe.
• The Taupo eruption is the most violent eruption in the world in the last 5000 years.
• Taupo is the most frequently active and productive rhyolite volcano in the world.
• Taupo caldera occupies an area about the same size as metropolitan Auckland.
• The Oruanui eruption produced enough material to produce three Ruapehu-sized cones.
• Floods associated with the eruption reached the coast down all major North Island rivers, burying the sites of present day Napier, Hastings and Wanganui.
• Pyroclastic flows destroyed 20,000 square kilometres of the central North Island, including rain forest that had been largely undisturbed since the last Ice Age
• If the same eruptions were to occur today, fall deposits would cause chaos from Hamilton to Palmerston North and damage or destroy buildings from Rotorua to Gisborne.
• The eruption devastated an area now populated by over 200,000 people.

It is not possible to predict when the next eruption will occur at Taupo, or what size it will be. From the information available there does not seem to be a relationship between the size of the eruption and the time since the last eruption. The next eruption might be next month, next year or in several thousand years. It might produce a small lava dome or it might destroy the central North Island as it has done in the past. All that is certain is that the volcano will erupt again.

In 1998 the JAGO minisubmarine explored Lake Taupo and for the first time we were able to see what was on the lake bed. This section of the NZMIA website details the JAGO exploration and backgrounds the formation of Lake Taupo. Includes explanations and diagrams.

The GNS site has extensive material on the Taupo Volcanic Zone.
http://www.gns.cri.nz/earthact/volcanoes/nzvolcanoes/taupo.htm

[coal]
[ironsands]
[JAGO]
[industrial minerals]
[aggregates]
[GNS]
[volcanoes]
[base & precious metals]
[rehabilitation]

[site map]
[overview]
[about NZMIA]
[minerals industry in New Zealand]
[resources for schools]
[research & development]
[mineral moments]
[what's new?]
[downloads]
[links to other sites]