Hydrosphere

Monitoring aquifers is essential to ensure the sustainable management of water resources, particularly in catchment areas near urban centers. Traditionally, aquifer monitoring relies on piezometric measurements or sensors such as tensiometers and neutron probes, which are difficult to maintain over long periods and offer limited spatial coverage.

Among the range of geophysical methods sensitive to changes in water content, passive seismic techniques; such as ambient seismic noise interferometry, offer an innovative solution for observing groundwater level variations with unparalleled spatial and temporal resolution, across multiple scales. Under certain conditions of seismic source stability, it becomes possible to reconstruct the seismic wavefield and detect subtle variations linked to poroelastic or fluid-related changes in the medium. This approach, now widely used in Earth sciences, demonstrates its full potential for non-invasive, high-resolution monitoring of the unsaturated zone and aquifers, at various scales, from laboratory experiments (Gaubert-Bastide et al., 2025), to near-surface monitoring using dense arrays (see Figure) or DAS (Gaubert-Bastide et al., 2022; Nziengui-Bâ et al., 2024), and even long-term observatory data (Mao et al., 2022).