SIMON FRASER / SCIENCE PHOTO LIBRARY SIMON FRASER / SCIENCE PHOTO LIBRARY
Pohutu geyser. Superheated water and steam being ejected from Pohutu geyser. This geyser gushes water to a height of 20-30 metres, erupting at least once per hour. Beneath the surface cone is a deep natural chamber; when this is full the geyser erupts. The term geyser comes from the Icelandic "geysir" meaning roarer or gusher. Geysers occur in geothermal rock fissures where water in the chamber is superheated by the surrounding rocks, but is prevented from boiling by hydrostatic pressure. The water expands, spills from the cone, and as the pressure falls the superheated water suddenly boils and erupts. Pohutu geyser is at Whakarewarewa, New Zealand.
Model release not required. Property release not required.