The Tongariro volcanic centre (TVC) has been shaped by the interaction of several natural processes. Some processes originate beneath the surface of the earth and have resulted in the building up of volcanic landscapes. However, climate processes operate on the surface, wearing down and shaping landforms.
Volcanism is a process that operates beneath the earth’s surface. It involves tectonic and volcanic processes responsible for building up relief features and mountains at the TVC. Mt Ruapehu, the highest point in the north Island of New Zealand at 2979 metres above sea level, is a distinct feature built by tectonic and volcanic processes. Over time the Pacific and Indo-Australian plates have collided causing eruptions and allowing for magma to rise to surface. During the eruption rock and materials are distinct and result in the building up of the landscape.
Ruapehu is a composite cone and has been built up of layers of lava and tephra. Pyroclastic flow, fast moving current of hot ash and rock, have resulted in the shaping of the landscape west of Ruapehu like Ngauruahoe and burnt and buried much of the land and vegetation on the east of which is now the Rangipo desert (see cross section in annotated diagram). Lahars are turbulent mixtures of water and volcanic debris which flow rapidly down the slope and have shaped parts of Ruapehu. During the 1953 Tangiwai disaster where 151 people died when a train was derailed, was a result of the heating up of the crater-lake on Ruapehu over time, causing mud and rocks with volumes of water from the Whangaehu river to not only destroy the railway line and people but in doing so, changed the nearby environment.
Mountain building affects climate. The TVC region lies between 39 and 39.5 degrees south of the equator and between 50 and 100 kilometres from the sea. Because of its latitude and distance