Waiotapu Mud Pools

Mud pools form in geothermal areas where rising steam and gas from deep boiling fluids condense in shallow groundwater or rainwater. The gases make the water acidic, and attack the surface rocks, forming clay. The clay-rich soil mixes with the pond water to produce a muddy, steam-heated slurry, or mud pool. Also present are small quantities of sulphur which can be seen as black slicks on the surface.
The mud pools at Waiotapu (Maori for sacred waters) occupy the site of what was the largest mud volcano in New Zealand. The original cone, present until 1925, is now eroded and vigorously active water and mud fill the pool. The gases and steam rising to the surface mean the pools are in a constant state of movement, with mud bubbles forming at surface and erupting. At times repeated mud eruptions at a location can form small mud volcanoes.

The thickness of the mud will depend on how much rain has recently fallen. In dry conditions, the mud is thick and sticky, and more likely to allow for mud volcanoes. In wet periods, the mud is more fluid and the pool may look more like muddy boiling water. Have a look and see how much rain you think has fallen recently.
Spend some time trying to capture a perfect mud plop in a photo!
Located at the other end of the Waiotapu Loop Road is a small bridge where you can park and take a swim in a hot geothermal stream (don't put your head under the water). Also located on the Waiotapu Loop Road is the large Waiotapu geothermal area, with the famous Champagne Pool. This has an admission fee.