The North Island of Aoteroa (New Zealand) is bursting with volcanic and geothermal activity. In some areas of the island you have the impression of walking on an unstable carpet floating over boiling water, which occasionally bursts out, giving rise to geysers, bubbling mud, steam. The reason for this anomalous thermal regime lies on the behaviour of the tectonic plates that are found in the area. The Pacific Plate, which is subducting underneath the Australian Plate, to the north east of New Zealand, is currently retreating very rapidly. As a result of this retreat (a process that geologists call slab rollback) the overlying plate, which contains also the North Island of New Zealand, has to stretch. This stretching results in thinning of the crust and of the lithosphere, which brings hotter rocks closer to the surface. These hotter rocks can generate magmas, which erupt to the surface and create volcanoes, and be the engine behind the geothermal activity.

Champagne pool, in Waiotapu 

The Taranaki volcano (in the far distance) seen from Ruapehu, which, at 2797 meters of altitude, is the highest vocano in New Zealand.