Spanning nearly the entire circumference of the Pacific Ocean, a horseshoe shaped series of volcanic phenomena that make up the “Ring of Fire” are anchored at one end by New Zealand. Oceanic trenches and 452 volcanoes are dotted around the perimeter, where all but 3 of the world's 25 largest volcanic eruptions of the last 11,700 years have occurred.
Volcanic activity in the zone started about 2 million years ago and continues today. Geologically speaking, the three volcanoes are comparatively young, being less than 500,000 years old. While its commonplace to refer to three volcanoes, both the indigenous Maori and geologists alike consider Mount Ngauruhoe to be a vent, built up as part of Mount Tongariro’s volcanic system.
The history of Mount Ruapehu and Mount Tongariro began before the last ice age and eruptions of Mount Ngauruhoe are thought to have occurred around 2,500 years ago. Mount Ruapehu and Mount Ngauruhoe are two of the most active composite volcanoes in the world, with Mount Ruapehu last erupting in 1996 and Mount Ngauruhoe in 1975.
In Maori legend, the high priest, Ngatoroirangi was caught in a blizzard while climbing Mount Ngauruhoe. He prayed to his sisters in Hawaiki to send him fire to save him from freezing. The flames they sent south emerged first at White Island, then Rotorua and Taupo before finally bursting at Ngatoroirangi's feet. Thus Ngatoroirangi is credited with bringing volcanic activity to Aotearoa New Zealand, not as a curse upon the land, but as a blessing.