Page 313 - Volcano and Geothermal Tourism

290 Oceania

Figure 19.1 Artist’s view of the White Terraces at Lake Rotomahana before they were
destroyed in 1886
Source: Blomfield, 1888

world’s biggest and most destructive eruption ever areas of more intensive and long-lived activity,
(the Oranui eruption produced 1170km of whose position (and the composition of the lavas
3
tephra). That event dwarfed the AD186 eruption. erupted) can be related geologically to the large-
Still active, the Rotorua–Central Plateau area scale movement (subduction) of the Indo-
contains many thermal reserves with examples of Australian and Pacific tectonic plates. Most New
boiling mud pools, hot springs, geysers, thermal Zealand volcanism in the last 1.6 million years has
rivers, boiling lakes, steam vents (fumaroles) and occurred in the TVZ. This is an elongated area
volcanic terraces. It is these that attract tourists to that extends from White Island to Mt Ruapehu
the region, and it is these along with the active (Figure 19.2) – a 250km-long zone of intense
volcanoes themselves that pose the extreme volcanism that marks the boundary of the
hazards for those tourists and their host Australian and Pacific tectonic plates. The TVZ is
communities that are the subject of this book. extremely active on a world scale: it includes three
Geological background frequently active polygenetic volcanoes (Ruapehu,
Tongariro/Ngauruhoe, White Island), and two
Simkin and Siebert (1994) credit the North Island major calderas (Okataina and Taupo). In a
of New Zealand as containing the world’s largest continuation of this chain of volcanic activity out
concentration of youthful rhyolitic andesite to the north, much of the seabed is made up of
volcanoes. However, like Japan the volcanoes here seamounts and small islands, including 16
are not randomly scattered but are grouped into submarine volcanoes.

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