North Island Volcanoes

DURING the same period in the North Island activity was even more intense and widespread. Thick lava-flows cover a great part of the centre of the island, and rising above this central plateau are the more recent cones of the Tongariro group. Mount Egmont, the almost perfect cone which dominates Taranaki, was formed at about the same time.

One of the most interesting volcanic areas is the Auckland Isthmus, where there are a large number of small cones so recent in origin that they retain their form perfectly. Of these Rangitoto is the largest and most famous. Still farther north Whangarei and the Bay of Islands were the scene of great volcanic activity.

Within historic times activity has been confined to the area comprising Ruapehu, Ngauruhoe, Tongariro, Tarawera, and White Island. Ruapehu (9,175 feet) must have been very active in Upper Tertiary times, but it is now more or less extinct. Nevertheless, at different times, notably in 1890 and 1906, the crater-lake has displayed violent geyser-like action. Its long history is perhaps not completed. Ruapehu’s neighbour, Ngauruhoe, is New Zealand’s most continuously active volcano, and mild eruptions occur every few years.

The most spectacular and disastrous eruption within recent times took place in 1886, when Mount Tarawera was split in two. A fissure some eight miles in length opened, and from a series of about twenty new craters an immense mass of fragmentary material was erupted. Ash-showers covered an area of 4,000 square miles and the eruption destroyed the famous Pink and White Terraces on Lake Rotamahana.

The volcanic districts of the centre of the North Island, from Ruapehu to Rotorua, have entered the dying stage of the volcanic cycle. The main activity has largely ceased, but hot springs, geysers, steam-jets, mud volcanoes, ‘ porridge-pots,’ and so forth still remain as signs of dying vulcanicity.