Residual Magnetization Accumulation Enables Rapid Pre‐Polarized Surface NMR Groundwater Detection

Abstract Surface nuclear magnetic resonance (SNMR) directly detects subsurface water, but its field application is constrained by the trade‐off between signal enhancement and survey throughput. Conventional pre‐polarization strengthens SNMR signals but requires long polarization pulses that markedly prolong acquisition. Here we show that repeated short pre‐polarization pulses can exploit inter‐cycle residual magnetization accumulation to sustain enhanced SNMR responses without long single‐cycle polarization. Theory and simulation indicate rapid early cycle buildup followed by convergence to a stable enhanced magnetization range. Forward modeling yields an initial amplitude of about 200 nV, close to the 213 nV obtained with conventional pre‐polarization, while reducing the excitation‐cycle duration from about 10 s to less than 1 s. Field experiments at a high‐noise groundwater site recover hydrogeologically consistent results and demonstrate that the shortened cycle can substantially reduce acquisition burden, providing a practical route toward higher‐throughput SNMR surveys for groundwater exploration in electromagnetically challenging environments.