Scientists are to launch two unmanned submarines in Lake Rotomahana to find out what happened to the Pink and White Terraces after the eruption in 1886 of Mt Tarawera.
They hope to launch the Automated Underwater Vehicles (AUVs) in the lake, near Rotorua, on 23 January.
Project leader Cornel de Ronde of GNS Science says researchers hope to spend about 10 days mapping the lake floor.
The AUVs will follow a pre-programmed path to help the team discover what happened to the terraces' hydrothermal system, he says.
The terraces were considered the eighth wonder of the world, until they were destroyed by the eruption of Mt Tarawera.