Volcanism of New Zealand

New Zealand's rocks record examples of almost every kind of volcanism observed on Earth, including some of the world's largest eruptions in geologically recent times.

[1] These include eruptions from Macauley Island and the Taupō, Whakamaru, Mangakino, Reporoa, Rotorua, and Haroharo calderas.

[8] Because its deposits, stretching from Gisborne to the Bay of Islands, were emplaced around the time that Māori permanently settled New Zealand, they have provided a useful archaeological marker.

Tarawera erupted again on 10 June 1886, spewing ash and debris over 16,000 km2 (6,200 sq mi), destroying the Pink and White Terraces and three villages, including Te Wairoa, and claiming the lives of perhaps 120 people.

[8] As well as the direct effects of explosions, lava, and pyroclastic flows, volcanoes pose various hazards to the New Zealand populace.

Twenty-two people died, either in the explosion or from injuries sustained, including two whose bodies were never found and were later declared dead.

It holds that the two first-named volcanoes competed for the love of the beautiful Pihanga and, after Tongariro succeeded, the defeated Taranaki moved to its lonely location near New Plymouth.

Another legend recounts the exploits of Ngātoro-i-rangi, a tohunga (priest) who arrived from the ancestral Māori homeland, Hawaiki, on the Arawa waka (canoe).

Fossilized footprints of perhaps second- or third-generation Polynesian colonists have been found in volcanic ash on islands in the Hauraki Gulf.

[19] The latest activity in the Kaikohe-Bay of Islands field, around 1300 to 1800 years ago, created four scoria cones at Te Puke (near Paihia).

[23] Remnants of these two ancient volcano belts are still exposed in many places, including Whangarei Heads, the Hen and Chickens Islands, around Whangaroa Harbour, Waipoua forest, and the Waitākere Ranges.

The field's many vents have produced a diverse array of explosion craters, scoria cones, and lava flows.

Currently dormant, the field is likely to erupt again within the next "hundreds to thousands of years" (based on past events), a short timeframe in geologic terms.

[25] Three volcanic fields erupted between 2.7 and 0.5 million years ago, migrating northwards from Mount Pirongia to the Bombay Hills.

Unlike typical hot spots such as the one underlying Hawaii, it does not seem to have stayed still, but instead is migrating northward at a faster pace than the surrounding Indo-Australian plate.

[33] Mayor Island / Tūhua is a peralkaline shield volcano with a caldera partly formed in a large eruption some 7000 years ago.

[36] Mount Ruapehu marks its southwestern end, and it continues up through Ngauruhoe, Tongariro, Lake Taupō, the Whakamaru, Mangakino, Maroa, Reporoa, and Rotorua calderas, the Okataina Volcanic Complex (including Mount Tarawera) and 85 kilometres beyond Whakaari / White Island to the submarine Whakatāne Seamount.

Beginning in the Sugar Loaf Islands, near New Plymouth, activity then shifted to Kaitake (580,000 years ago) and Pouakai (230,000 years ago) before creating the large stratovolcano called Mount Taranaki, (former name Mount Egmont), which last erupted in 1854, and its satellite vent, Fanthams Peak.

[37] This southeastward migration is the continuation of the 25 million year activity of the Northland-Mohakatino Volcanic Belt that extends mainly under the present Tasman Sea from the west of Northland down to Mount Taranaki.

[41] The Alpine Dyke Swarm of volcanic intusion took place about 25 million years ago and is located near Lake Wānaka in the Southern Alps.

[43] The Solander Islands, a small chain of uninhabited islets close to the western end of the Foveaux Strait, are the emergent portions of a large extinct andesitic volcano that last erupted around 50,000 to 150,000 years ago.

A band of granitic intrusions covering over 10,000 km2, the Median Batholith, stretches from Stewart Island / Rakiura through Fiordland, and again through the West Coast and Nelson after interruption by the Alpine Fault.

This was produced between 375 and 105 million years ago in the course of subduction-related volcanism in a long mountain range along the Gondwanan coast somewhat like today's Andes.

Ultramafic intrusions are found in Marlborough and north Canterbury, including at the summit of Tapuae-o-Uenuku, the country's highest mountain outside the Southern Alps.