Hear Graeme Hill's full interview with Dr. Cornel de Ronde with here.
The New Zealand and US scientists who found part of the Pink Terraces in January can today confirm they have also found parts of the White Terraces on the floor of Lake Rotomahana.
A scan of the lake floor collected on the last day of the 10-day project at Lake Rotomahana last summer shows the find.
Using new software, which became available after data collection had finished, the team found the sonar data contained images of hard, crescent-shaped structures on the lake floor. The crescents were in a similar location to where the White Terraces stood before Mt. Tarawera erupted in June 1886.
It is 125 years to the day since the Pink and White Terraces were buried by the eruption of Mt. Tarawera. They were New Zealand’s number one tourist attraction prior to the disaster.
Project Leader Cornel de Ronde, of GNS Science, said the images showed the lake floor completely covered by soft sediment and mud.
“The two places on the lake floor where we encountered hard, up-standing crescent-shaped features correspond to the locations of the Pink and White Terraces before the Tarawera eruption,” Dr de Ronde said.
“The sonar image that appears to show part of the White Terraces came to light after the project had finished. It shows a horizontal segment of terraces over 100 meters long, although we don’t know which part of the terraces it is.
“The rounded terrace edges are standing up from the lake floor by about a metre in some places. The sonar images of both sets of terraces are strikingly similar.”
The team managed to snap a number of colour photographs of parts of the Pink Terraces in January, but an underwater camera was not lowered over the White Terraces as they weren't aware of what the sonar data was showing at the time.
The fate of the remaining sections is unknown. The eruption may have completely destroyed them. Alternatively, they may be lying, preserved under thick sediment that sonar signals sent out by the two autonomous underwater vehicles (AUVs) used in the survey cannot penetrate.
Dr de Ronde said the discovery of remnants of both sets of terraces was an excellent result for the project.
“The project team was absolutely thrilled in January when we realised our AUVs had detected remnants of the Pink Terraces. Finding part of what we believe is the White Terraces as well has been surprising and very satisfying.
“The original aim of the project at Lake Rotomahana was to map the lake floor and investigate the extensive geothermal system under the lake and how it evolved from an on-land geothermal system to a submerged one. Anything else was a bonus,” Dr de Ronde said.
“It’s gratifying to be part of a science project that can answer a century-old mystery about the fate of the Pink and White Terraces.”