The shallow shear-wave velocity structure of the subsurface is a key input for dam engineering, civil construction, and earthquake hazard assessments. Many commercial solutions lack sensitivity in resolving complex shallow Vs structure. Here we develop a frequency-time analysis approach for shallow active source seismic data, and demonstrate its sensitivity to common depth ranges of geotechnical investigations. We show the approach’s effectiveness in isolating the fundamental mode in group-velocity maps of Rayleigh waves, typically acquired in one-component geophone active surveys. We present a number of examples, ranging from construction to hydrogeological investigations, demonstrating FTAN’s ability to resolve complex shallow structures and its high visual correlation with independent geotechnical information, such as logs. Sensitivity kernel calculations show that FTAN has significantly more depth penetration than equivalent active techniques like refraction, at given shot-receiver distances, raising the possibility of processing legacy survey data for greater depth resolution and Vs structure.