Tongariro (6,458 ft), after which Tongariro National Park is named, is a truncated multiple volcano 9 miles long and 5 miles wide at its base with a summit 5 miles long and 2 miles wide. It is a multiple volcano in that the broad summit contains a considerable number of small craters including North Crater, South Crater, Central Crater, West Crater, Red Crater, Te Mari Craters, and Oturere Crater. It appears likely that these are later centres of activity within the rim of the remains of an earlier multiple volcano disrupted by explosion and collapse. A reconstruction of the form of the old volcano suggests that there were four craters forming an elongated volcano aligned north-west. On the northern slopes of Tongariro are a number of small explosion craters. Since 1840 there have been eruptions from three centres on Tongariro. Red Crater erupted ash in 1855 and steam in 1859. Variations of considerable extent in steam emissions, still continuing, have been reported. Te Mari consists of two craters. The lower, called Sulphur Lagoon, is filled with water and, according to the Maoris, has been frequently active in the past. The upper, formed during an eruption in 1869, emitted ash up to 1896 but since then its only activity has been fumarolic. A lava flow was erupted from the upper crater, probably in the 1880s.
To the west of Te Mari and somewhat lower (4,500 ft) is an area of fumaroles and hot springs, Ketetahi. Although Sir George Grey claimed to have reached the summit of Tongariro on 31 December 1866, it was probably Ngauruhoe that he climbed, seeing nothing but mist. The first definite ascent was made by Sir James Hector on 23 November 1867. Earlier attempts by travellers to climb the mountain were frustrated by the Maoris who regarded it as tapu.
Tongariro is traditionally the belly of the fish that Maui caught and there are many Maori legends concerning the mountain. Sir George Grey records that Ngatoroirangi, the archpriest of Arawa canoe, saw the summit of Tongariro and commenced to climb to it. Before he left his followers, he bade them to fast until his return. When he was nearly at the top, his followers disobeyed him and Ngatoroirangi all but perished. Almost at his last gasp, he prayed to his gods in Hawaiki to send fire and produce a volcano in the mountain. His prayers were heard, and the gods sent fire which came to him by way of Whakaari (White Island), Moutohora, Okakaru, the Rotorua thermal district, Tarawera, Paeroa, Orakeikorako, and Taupo. It travelled underground, spouting up at these places, and finally ascended to the top of Tongariro to revive him. The Tuwharetoa tribe has a variant of this legend, which explains the birth of the volcanoes and the naming of Tongariro and Ngauruhoe. According to this version, Ngatoroirangi had visited the Taupo – National Park district in order to lay claim to the territory. Near Rangipo he met Hapekituarangi who, he discovered, was on a similar errand. In order to forestall his rival, Ngatoroirangi decided to climb Tongariro and thus lay claim to whatever lands he could view from the summit. After rendering the mountain tapu to his rival, he began his climb. When he reached the summit he was chilled almost to death by the strong south wind. Weakened by the cold and the strenuous climb, he called aloud to his ancestral spirits and to his powerful sisters, Kuiwai and Haungaroa, who were in Hawaiki, to send fire to warm him. His call was answered, in the manner described by Grey. The name, Tonga-riro, commemorates the cold south wind, which chilled Ngatoroirangi.
by Bernard John Foster, M.A., Research Officer, Department of Internal Affairs, Wellington and Thomas Ludovic Grant-Taylor, M.SC., New Zealand Geological Survey, Lower Hutt.