Page 315 - Volcano and Geothermal Tourism

292 Oceania

Figure 19.3 Mt Ngauruhoe, the tallest peak of the Tongariro complex on the North Island of New Zealand
Source: Photo courtesy of Don Swanson

preceding 300 years. Deposits around the base 10,000 years, but the Rotorua–Whakarawarewa
record intermittent activity at this site over the last area is internationally recognized for the hot
130,000 years, and while these eruptions have not springs, geysers and other geothermal features that
occurred at regular intervals there has been a support a significant tourist industry.
moderate or major sized eruption on average White Island-Whakaari, the northernmost
every 340 years, with numerous smaller events at active volcano in the TVZ, is the summit of a large
more frequent intervals. There is therefore no (16 by 18km) submarine volcano which has
evidence to suggest Mt Taranaki has finally ceased grown up from the sea floor at between 300 and
erupting – rather it must be regarded as an active 400 metres depth. Only half the height and a very
volcano in a state of quiescence and is one of a small proportion of the volume of this volcano are
number of volcanoes in New Zealand where above sea level. Sitting 48km offshore, the island
future eruptions are to be expected (Newhall and has been built up by continuous volcanic activity
Dzurisin, 1988). over the past 150,000 years. The island has a
The Rotorua caldera lies near the western history of long periods of continuous hydrothermal
margin of the TVZ. This formed as a result of the activity and steam release, punctuated by small-to-
eruption of 200km (dense-rock equivalent) of medium eruptions (White Island Tours, 2010).
3
Mamaku ignimbrite from a lava dome collapse Between 1976 and 1993 White Island was more
over 10,000 years ago. Subsequent lava dome active than at any time in the past few hundred
eruptions in the caldera, from one to ten cubic years, and ash from its 1998 eruptions was
kilometres in volume, have not been dated, but recorded as far inland as Rotorua. The volcano’s
have formed several crater lakes that are now activity is often visible to people in Bay of Plenty
tourist attractions. No eruptions (other than with gas and ash plumes rising as high as ten
hydrothermal explosions) are known from the past kilometres on clear, still days. Craters and fumaroles

Ch19.indd 292 3/28/2010 1:31:53 PM