The BLiSS model: Four-way triangulation of a buried 293-m horizon at the White Terrace site, Taupō Volcanic Zone

Rex Bunn 

Following the 1886 Mount Tarawera eruption, the Pink and White Terraces, New Zealand’s Eighth Wonder of the World, were widely assumed to have been destroyed and/or submerged in the new Lake Rotomahana, which formed in the Rotomahana crater. This research records how independent historical, geological, topographic, and geophysical evidence can be combined to solve a problem that none of these could solve alone. This study presents an interdisciplinary forensic examination of the Te Tarata (White Terrace) site using a four-way triangulation model, i.e., BLiSS—engineering boreholes, high-resolution light detection and ranging, passive seismic (horizontal-to-vertical spectral ratio) exploration, and Ferdinand Hochstetter’s and Josiah Martin’s terrestrial survey datasets (together with altimetry). The convergence of these four independent datasets is consistent with a structural boundary at 293 m above sea level, corresponding to the pre-eruption Rotomahana Basin surface. This research suggests that the 1859 Rotomahana Basin landscape, including the White Terrace location, remains largely in situ, enrobed with hydrothermal ejecta. These findings are consistent with Nairn’s canonical eruption geometry of the Tarawera eruption. The pattern of fissures, vents, and surge directions that Nairn mapped across the basin was incapable of accounting for the destruction of the White Terrace at its surveyed location. The four research skeins conclude that at the White Terrace latitude, longitude, and altitude coordinates, the pre-eruption landscape remains largely unaffected by eruptive changes, apart from burial on the Lake Rotomahana floor, which was ejected over the coordinates by a sequence of hydrothermal eruptions. The White Terrace coordinates appear to be buried beneath tens of metres of soft hydrothermal sediments.