The cascading Pink and White Terraces were buried by the eruption of Mt Tarawera. Up to then, they had been New Zealand's premier tourist attraction.
The research was carried out by GNS Science after a remote-controlled submarine discovered fragments of the terraces last year.
Project leader Cornel de Ronde says his team used a special form of sonar to create a high-resolution three-dimensional map of the lake.
Dr de Ronde says the map found no trace of the White Terraces but did reveal a large area of hard rock exactly where the Pink Terraces were before the eruption, buried under about two metres of sediment.
He says it is difficult to know how well they have been preserved, but there is some suggestion that a promotory may have shielded them.
Dr de Ronde says the survey also found new volcanic craters and spots where hundreds of tonnes of gas is being released under the lake surface.
He says this suggest Mt Tarawera is more active than Mt Ruapehu and monitoring equipment should be installed.