Wai-O-Tapu is a highly active geothermal field in the North Island of New Zealand in the Taupo Volcanic Zone. It covers about 18 square kilometres (6.9 sq miles). Its name comes from the Maori word for ‘sacred waters’. The area has been protected as a scenic reserve since 1931 but is operated as a tourist business, in spite of which there are several areas where visitors are allowed to roam freely.
The reserve has been sculptured by geothermal activity resulting in some unique volcanic features. Calderas and rock pits, as well as natural hot water streams and pools are located throughout the area. Constantly bubbling hot springs are brilliantly coloured due to the chemicals in the water. Some are suitable for bathing, but others are highly acidic.
Wai-O-Tapu has New Zealand’s largest remaining sinter terrace after the eruption in 1886 of Mount Tarawera which destroyed the former Pink and White Terraces, believed to have been the largest sinter terraces in the world. Sinter terraces are formed when hot springs splash silica rich water around their shore line which because of the heat quickly evaporates, and over time forms beautiful, sculptural terraces.