Mapping Large‐Scale Deep Soil Moisture Variations Using Ambient Seismic Noise

Abstract Soil moisture is an essential ecosystem resource and a major control of the Earth's hydrological cycle and energy balance, closely interacting with the climate system. However, investigating deep soil moisture dynamics at large scales presents significant challenges due to the sparse distribution and limited spatial representativeness of in situ monitoring networks, while various remote sensing methods mainly address surface soil moisture within the top few centimeters. This study illustrates how seismic waves can effectively detect variations in deep soil moisture. We examine continuous seismic data from 791 stations across South‐Central Europe for the period 2016–2020. Our findings confirm a strong correlation between variations in seismic velocity and deep soil moisture content. Notably, the seismic observations pinpoint areas impacted by severe soil moisture deficits related to the 2016–2017 European drought event. The seismic method presented in this study offers new opportunities in addressing the observational gap of this critical environmental parameter.