Integrating satellite remote sensing and proximal data to investigate the role of brittle tectonics in the distribution of geothermal surface manifestations. Insights from the Parco Naturalistico delle Biancane - Larderello geothermal field (Southern Tuscany, Italy)

Geothermal surface manifestations (e.g., fumaroles, hot springs, geysers, mud-pots, mineral alterations) and thermal anomalies are some of the main indicators of a potential geothermal field. They can be detected by Thermal Infrared (TIR) Remote Sensing satellite data (e.g., Landsat 8 and ECOSTRESS). In this work, we propose a methodology involving image processing techniques combined with field data to investigate the distribution of thermal anomalies and their relationship with the morpho-structural domains related to the tectonic framework in the “Parco Naturalistico delle Biancane” (PNB) area in Southern Tuscany (Italy). A multiscale approach was applied, analyzing spatial distributions of geothermal domains in relation to structural elements, in order to contribute to understanding how tectonics controls the circulation and geothermal fluid upwelling. An automatic lineament domain analysis has been applied to Digital Elevation Models (DEM), Land Surface Temperature (LST) maps, and high-resolution FLIR thermal images from drones. The data allowed analysis at different spatial resolutions (SR): DEM and LST (30 m resolution) for regional-scale comparisons of structural and thermal fields, and FLIR thermal maps (0.25 m resolution) to explore local-scale relationships between structural features and thermal anomalies observed in the field. Surface temperature maps, derived from satellite and drone data, highlight thermal lineaments and thermal fractures parallel to SW-NE and NW-SE structural systems, which control the upwelling of geothermal fluids. These thermal anomalies are bounded by an N-S structural system (i.e. faults). The study demonstrates that remote sensing techniques can effectively derive heat flow and thermal lineament maps, reflecting fluid circulation contributions. This methodology provides critical insights into the tectonic controls on geothermal systems, offering valuable tools for geothermal resource exploration and assessment. Moreover, it demonstrates the potential of upcoming TIR satellite missions—such as NASA-ASI Surface Biology and Geology SBG-TIR, ISRO–CNES TRISHNA, USGS-NASA Landsat Next, and ESA’s LSTM mission—to enhance the detection and characterization of geothermal features.