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Overview
Tuhinga 30: 178-208
ABSTRACT: The disappearance of Lake Rotomahana’s Pink and White Terraces in the 1886 Mt Tarawera eruption meant the loss of the ‘eighth natural wonder of the world’. The unique geothermal features were either destroyed or left unrecognisable, and other landmarks were eventually submerged. This led to conflicting opinions on the locations and fates of the terraces. In the current decade, the rediscovery of a pre-eruption geological feature led to a photogrammetric map by Ronald Keam predicting that extant terrace features would be submerged in the lake close to the shore (de Ronde et al. 2016a), while the discovery of a pre-eruption topographical sketch map by Ferdinand von Hochstetter resulted in a counter-claim that the terraces are buried onshore (Bunn & Nolden 2017). The projection of pre-eruption photographic sight lines onto a topographic map led to a third claim that the terrace sites were further offshore and consequently destroyed (Keir 2017). More recently, confirmation of the accuracy of a published map by Hochstetter led to the conclusion that the terrace locations lie within the confines of the current lake (Lorrey & Woolley 2018). To resolve this ‘battle of the maps’, we assembled a pre-eruption lake panorama and used spatial technology to project the current lake level onto the pre-eruption landscape and to determine terrace bearings. When plotted on a topographic map, those bearings intersect terrace bearings derived from another early photograph, confirming the terrace sites are within the current lake, relatively close to the shoreline. Furthermore, comparison of pre- and post-eruption photographs indicates that while some Pink Terrace features might be extant, this is unlikely to be true of the White Terrace.
KEYWORDS: Pink and White Terraces, Tarawera eruption, photogrammetry, forensic cartography, digital spatial technology, sight-line analysis, virtual horizon software, digital elevation model, bathymetric map.