chapter  19
13 Pages

Volcanic Landscapes of New Zealand: M. Cooper

ByNew Zealand M. Cooper

The biggest and most dangerous volcano in Aotearoa-New Zealand and the world is actually Taupo, which presently has the country’s largest lake in its caldera and is in the Rotorua-Central Plateau area of the North Island (Froggatt, n.d). This volcano, which has been in existence for more than 65,000 years last erupted in the year AD186, and erupts approximately once every 2000 years. The AD186 eruption was over 50 times the magnitude of the recent Mt St Helens eruption in the USA (Mt St Helens removed 3km3 of earth, and Krakatoa (the biggest eruption in recent times) in Indonesia moved 8km3 in 1887, but Taupo removed 110km3 in AD186). This eruption is regarded by volcanologists as the largest of the last 5000 years, and was recorded by Chinese and Roman chroniclers (e.g. Herodian of Antioch, 1961) The Chinese apparently actually heard the eruption and made a record of the brilliant sunsets that lasted for approximately six months (Wilson et al, 1980). Prior to this eruption, about 22,000 years ago Taupo experienced the

Introduction Tectonically, Aotearoa-New Zealand lies on the rim of the Pacific Plate which meets the IndoAustralian Plate at this point on the Earth’s surface. Similar geological processes occur here as with Japan, the west coast of the United States and the rest of the Pacific Rim. However those at work in the North Island of New Zealand are a result of the Pacific Plate sliding under the Indo-Australian Plate, while those of the South Island are a result of the two plates directly meeting each other. This latter collision has created the Southern Alps mountain range. In the North Island, the result of the geological process is volcanic activity and this is centred in Rotorua and the Central Plateau area of the Island, collectively known as the Taupo Volcanic Zone (TVZ). Mt Tongariro, which gives its name to the national park that is the primary focus of this chapter, Mt Ngauruhoe and Mt Ruapehu are the three main volcanoes at the Central Plateau end of the TVZ. These volcanoes are active – Mt Ruapehu as recently as 1995 and 1996 and Mt Ngauruhoe in 1972 – and it is this fact that both creates and constrains the patterns of tourism found in this area.