Exploring geothermal potential with robust satellite techniques using MODIS LST data

Abstract

Thermal infrared remote sensing is an emerging technique for detecting geothermal anomalies in volcanically and tectonically active regions. This study evaluates its applicability for geothermal prospecting and thermal activity monitoring in southwestern Yunnan, China-a remote frontier characterized by dense vegetation and complex terrain. Despite its considerable geothermal potential, the region remains underexplored due to limited accessibility and the lack of long-term thermal monitoring. We applied Robust Satellite Techniques (RST) to 21 years (2003-2023) of MODIS nighttime Land Surface Temperature (LST) imagery. Thermal anomalies were extracted using the RETIRA index (threshold ≥ 4) with a cumulative frequency cutoff of ≥ 30. Anomalies were most prominent at intersections of active faults, with the most favorable geothermal zones occurring where anomalies coincided with mapped fault structures. A distinct W-shaped anomaly belt, consistent with previous surveys, was delineated in the Lianghe-Tengchong region. Of 61 known geothermal sites, 38 (∼63%) were detected using LST anomalies alone; this increased to 84% when fault data were incorporated. In Yingjiang County, anomalies aligned with historical seismic swarms, while in Longling, they corresponded with both earthquakes and hot springs, suggesting a fault-thermal-seismic relationship. Although hydrothermal alteration zones showed only partial spatial overlap with thermal anomalies, they further support the role of faults in facilitating subsurface heat transport. These findings demonstrate that RST, when applied to long-term MODIS LST data, provides an effective and scalable approach for geothermal exploration in tectonically active and data-scarce regions.