Investigating structural controls on the heat flux and steam release from the Waiotapu Geothermal Field using the Landsat 9 dataset

Abstract

Geological (tectonic and volcanic) structures control the flow of hot fluids in rift settings. Geothermal fluids transported to the surface through permeable pathways bring heat energy associated with steam release that can be examined by mapping anomalously hot areas. This study explores the structural influence on the spatial pattern of the surface heat flux and the total heat and steam released from the ground at the Waiotapu geothermal field. We investigated structural fabrics and spatial patterns of surface heat flux from the Waiotapu geothermal field, the largest of 20 major high-temperature geothermal fields in the Taupo Volcanic Zone (TVZ), New Zealand. Landsat 9 datasets and ground measurements were processed and analysed using Python and QGIS to calculate land surface temperatures for the Waiotapu area and its surroundings. Land surface temperatures are used to estimate heat fluxes. The spatial distribution of heat fluxes at Waiotapu and its surroundings correlates well with mapped structural features using the 30 m-resolution Shuttle Radar Topography Mission (SRTM) DEM dataset. This indicates that tectonic and volcanic structures control the spread of heat flux anomalies. The total heat flux from the land surface and associated steam release at Waiotapu is calculated as 547.5 ± 20.1 MW. This high value underscores the role of the geothermal field contribution to the heat and steam budget of this rift and the overall importance of the Taupo Volcanic Zone influence on the atmosphere.