The Volcanic Plateau stretches south-west from the Bay of Plenty coast to Mt Ruapehu in the central North Island. About 180 kilometres from the coast to the mountain, and 100 kilometres wide at most, it is bounded to the east by the North Island main ranges, and to the west by older formations – the Mamaku Plateau and the Hauhungaroa Range.
Unpredictable and fascinating, the Volcanic Plateau is New Zealand’s main area of volcanic activity. In this zone, the Pacific tectonic plate is sinking beneath the Australian Plate. At a certain depth its rocks heat and produce volcanic activity, which erupts at the surface in minor ways (steam vents, mud pools and hot springs), and major ways (volcanic eruptions, collapsing mountains and lake formation).
The region of eruption sites known as the Taupō Volcanic Zone stretches from Whakaari (White Island) in the Bay of Plenty to Mt Ruapehu. This ‘line of fire’ is part of the huge ‘ring of fire’ around the Pacific Ocean.
The Volcanic Plateau itself is the product of massive eruptions from the Taupō Volcanic Zone. These deposited layers of ash and rocks over about a sixth of the North Island. The area is considered a plateau, rather than a plain, because it is well above sea level – 280 metres at Rotorua, rising to 370 metres at Taupō.
The Kāingaroa Forest area, in particular, is as flat as the Canterbury Plains. Standing in that landscape, one does not look up to mountains, nor out to sea or a lake, but across an even terrain with a wide horizon.
The volcanoes at the plateau’s southern end, Tongariro (1,967 metres), Ngāuruhoe (2,291 metres) and Ruapehu (2,797 metres), are three of the four highest summits in the North Island. The Desert Road section of State Highway 1, skirting the eastern side of these mountains, reaches 1,074 metres – the highest point of any main road in the North Island.
A volcano-formed landscape
There are many lakes on the Volcanic Plateau. Apart from recent man-made ones, they are the result of volcanic activity. Lake Taupō (357 m above sea level) is both New Zealand’s biggest lake and its largest volcano.
The upper course of the Waikato River, New Zealand’s longest, has also been shaped by volcanism. It rises on the slopes of Mt Ruapehu and, as the Tongariro River, flows into Lake Taupō. From Taupō to Waipapa on the edge of the plateau, it cuts down deeply into recent volcanic deposits.
Volcanism has given the plateau its geothermal springs, drifting steam and pervasive aroma of sulfur – also described as a smell of rotten eggs. These can be experienced most intensely on still, cold nights, as a bather races from a changing room through frosty sulfur-scented air to the languor of an outdoor hot pool. Hot springs and related volcanic activity are found throughout New Zealand, but nowhere in such concentrations as on the Volcanic Plateau.
Descendants of the early arrivals from Polynesia settled around the shores of the Rotorua lakes and Lake Taupō – particularly where they could take advantage of geothermally heated water and steam, as well as the lakes’ fresh water.
All the hapū (sub-tribes) in the region can trace their lineage to the Te Arawa canoe, which made landfall at Maketū, in the Bay of Plenty. The name Te Arawa usually describes the people who live around Rotorua, whilst those at Taupō identify with their ancestor Tūwharetoa.
For 19th-century Pākehā, the Volcanic Plateau was both appealing and difficult. It was open country, relatively easy to traverse, and had a fascinating geology and landscape. But its soils were not suited to farming – and there was no gold.
The government developed a tourist town at Rotorua, and from 1900, anglers from around the world came to fish for trout in the region’s lakes and rivers. From the 1920s, better roads, timber, electricity and improvements to soil saw the whole region develop.
Towns and local government
Rotorua and Taupō are the main urban centres of the Volcanic Plateau.
The region comprises the Rotorua and Taupō local government districts. Rotorua district lies partly within the territory served by the Bay of Plenty regional council. The rest of Rotorua district and Taupō are served by the Waikato regional council. While Tokoroa, Kawerau and Murupara are on the plateau geographically, they are not within either district. Tokoroa is in the South Waikato district and Kawerau and Murupara are part of eastern Bay of Plenty. The summit of Ruapehu is on the regional boundary.