Hyperspectral Imaging Techniques in Search of Geologic Hydrogen: A Review

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New energy sources are crucial for powering next-generation transportation and supplying reliable energy in remote regions. Hydrogen is an attractive energy carrier because its utilization produces only water as a byproduct. However, conventional industrial hydrogen production, primarily via steam methane reforming, is carbon-intensive and associated with substantial CO2 emissions. This has motivated increasing interest in naturally occurring and stimulated geologic hydrogen as a potentially low-carbon resource. Geologic hydrogen is commonly generated through serpentinization, a water–rock reaction in which ultramafic rocks interact with water, producing serpentinite and molecular hydrogen (H2). The identification of geological environments favorable for hydrogen generation and migration is therefore of growing importance. Hyperspectral imaging (HSI) provides detailed spectral information that enables the detection and characterization of surface minerals and alteration products associated with serpentinization and related processes. This article reviews the applications of HSI techniques for indirect geologic hydrogen exploration. Hyperspectral data can assist in mapping iron-rich and serpentinized lithologies, identifying alteration halos, and detecting vegetation stress or compositional changes potentially linked to hydrogen seepage. These capabilities are applicable across multiple platforms, including airborne HSI, drill-core analysis, and underwater hyperspectral systems. In addition, spectral anomalies observed near so-called “sub-circular depressions” —sub-circular barren features whose origin remains debated—are discussed in the context of potential hydrogen seepage. Together, these approaches highlight the potential of HSI as a complementary tool for indirect geologic hydrogen exploration.