Volcanology of New Zealand

Volcanology of New Zealand is the scientific study of volcanoes and volcanic phenomena in New Zealand. Volcanism has been responsible for many of the country's geographical features, especially in the North Island and the country's outlying islands.

While the land's volcanic history dates back to before the Zealandia microcontinent rifted away from Gondwana 60–130 million years ago, activity continues today with minor eruptions occurring every few years. This recent activity is primarily due to the country's position on the boundary between the Indo-Australian and Pacific Plates, a part of the Pacific Ring of Fire, and particularly the subduction of the Pacific Plate under the Indo-Australian Plate.

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.

None of the South Island's volcanoes are active.

New Zealand has been the site of many large explosive eruptions during the last two million years, including several of supervolcano size. These include eruptions from Macauley Island and the Taupo, Whakamaru, Mangakino, Reporoa, Rotorua, and Haroharo calderas.

Two relatively recent eruptions from the Taupo volcano are perhaps the best known. Its Oruanui eruption was the world's largest known eruption in the past 70,000 years, with a Volcanic Explosivity Index (VEI) of 8. It occurred around 26,500 years ago and deposited approximately 1,200 km³ of material.Tephra from the eruption covered much of the central North Island with ignimbrite up to 200 metres (650 feet) deep, and most of New Zealand was affected by ash fall, with even an 18 cm (7 inch) ash layer left on the Chatham Islands, 1,000 km (620 mi) away. Later erosion and sedimentation had long-lasting effects on the landscape, causing the Waikato River to shift from the Hauraki Plains to its current course through the Waikato to the Tasman Sea. New Zealand's largest lake, Lake Taupo, fills the caldera formed in this eruption.

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