Northeast of Ruapehu, Mt Ngauruhoe (2287m) is the North Island's youngest volcano. Its first eruptions are thought to have occurred 2500 years ago. Until 1975 Ngauruhoe had erupted at least every nine years, including a 1954 eruption that lasted 11 months and disgorged six million cu metres of lava. Ngauruhoe is a conical, single-vent volcano with perfectly symmetrical slopes – which is the reason that it was chosen to star as Mt Doom in Peter Jackson's Lord of the Rings .
