Basin-wide assessment of land deformation in the salar de atacama (2019–2024) and implications for monitoring under brine extraction

Recent satellite-based analyses (Delgado et al., 2024) have reported centimeter-scale subsidence in parts of the Salar de Atacama and raised concerns that continued brine extraction could lead to cumulative basin-scale ground lowering and associated environmental impacts. We evaluate whether basin-scale deformation is evident during 2019–2024 using Sentinel-1 Interferometric Synthetic Aperture Radar time series processed with a Small Baseline Subset approach. The six-year record provides millimeter-scale sensitivity to line-of-sight surface motion and allows us to test whether deformation compatible with subsidence is spatially extensive or confined to localized sectors. Results indicate that the Salar de Atacama does not exhibit basin-wide subsidence during 2019–2024. Deformation is spatially heterogeneous, with a slight basin-average motion toward the satellite of approximately + 0.38 cm/yr and localized areas of line-of-sight motion away from the satellite that may reflect minor subsidence where horizontal contributions are small. Areas overlapping evaporation ponds are interpreted cautiously because liquid surfaces reduce coherence, but deformation patterns outside these zones are spatially consistent. Overall, the observations do not provide evidence for basin-wide ground lowering over the study period; any linkage to brine extraction cannot be uniquely inferred from the available data. Continued monitoring should integrate satellite geodesy with hydrogeological and geological characterization, complementary viewing geometries and/or in situ geodetic measurements to better resolve deformation components and drivers.