Preliminary Remote Spatial Analysis of Fairy Circles: an Approximation of Hypersectral and Geophysical Data from Hydrogen Seeps

We present a remote sensing analysis to identify potential concentrations of natural hydrogen by observing fairy circles. Utilising Principal Component Analysis (PCA), distinct features of these formations were delineated, indicating their differentiation from the surrounding environment. It was noted that such distinctiveness occasionally arose from the presence of water and similarities in topography, which also manifested in the PCA contours of the fairy circles. The role of water or humidity emerged as significant in the Thermal Infrared (TIR) response of fairy circles, typically displaying negative anomalies. However, this correlation appeared less straightforward in specific cases such as Brazil. Band ratio methods revealed a pronounced association with ferric iron (Fe+3) and a less conspicuous link with Alunite-Kaolinite. Additionally, vegetation indices primarily correlated with Normalised Difference Vegetation Index (NDVI) and Moisture Stress Index 1 (MSI1) in agricultural areas, and MSI1 and Water Index 1 (WI1) in water body regions, with other indices (e.g., OCVI, NDWI, and CIG) proved beneficial. Radiometric analysis suggested that low K/Th values were associated with this anomaly in Western Australia, whereas other radiogenic elements did not exhibit clear patterns in the areas studied. Future research directions are proposed, advocating utilising high-resolution geophysical data to gain deeper insights into the associations linked to fairy circles. The implementation of unsupervised and supervised classification algorithms was deemed crucial for identifying new formations, while longitudinal analysis would aid in understanding the evolving nature of these phenomena over time.