Maori tradition, has been constant for the last 200 years and the Maoris of the early days of New Zealand used this column of steam as a beacon to guide them with their canoes across Lake Taupo which is six miles distant.” An information leaflet of New Zealand Railways of 1940 speaks about the “Inferno of Karapiti”. The phenomenon was usually viewed at night. A piece of smouldering sacking was applied to the blowhole. Then the “jet, filled with smoke and burning shreds becomes a whirling inverted cone flashing with thousands of yellow sparks in a brilliant pyrotechnic display”. In 1950 the area was described as being mostly warm clay with small patches of hot ground and mudpools. “The Karapiti Blowhole was still impressive, though apparently much less intense than when Hochstetter saw it”. A most important change in the region has been the building of the Wairakei Power Station (150 MW) in the 1950s, about 2 km. north of the field. This reduced the pressure in the hot water systems below the earth surface. Since then much of the geothermal activity in the region has dramatically changed, as did the geothermal activity at Craters of the Moon. The geysers at Wairakei Geyser Valley totally disappeared, but the heat output at Craters of the Moon increased. A lot of hydrothermal eruptions occurred, which formed the craters. In 1950, the total heat output at Craters of the Moon was about 40 MW (megawatts). By 1958, it had increased to about 90 MW. In 1964 it was 420 MW. After 1964 the output declined to about 220 MW in 1979. The most recent estimate being about 200 MW in 2000. Heat output from the Karapiti Blowhole followed a similar pattern. In the 1950 it was 12 MW. It increased to a maximum of about 38 MW during the mid 1960s. Then it dropped to about 7 MW in 1978. The blowhole finally ceased altogether in 1987. Features of Craters of the Moon Craters of the Moon is a steamfield with a total of about of heated ground. It has an average altitude of 435 m. It has – of course – craters, but it also has fumaroles (“blowholes”) and a mudpool. Vegetation around the area of the Craters of the Moon is quite uncommon. Craters All the craters at The Craters of the Moon are the result of hydrothermal eruptions. The pressure