In linear infrastructure projects, such as bridges, the spatial variability of soil properties—particularly in soft lacustrine clays like those in northern Bogotá—significantly influences foundation design. Due to the limited penetration of active methods, passive surface wave techniques, specifically SPAC, were applied to characterize deep soil layers. Surveys at three sites used L-shaped and linear arrays with 1 Hz and 4.5 Hz geophones spaced at 4 m. Ambient noise recordings yielded clear dispersion curves between 0.8 and 20 Hz. Non-linear inversion provided 1D shear-wave velocity (Vs) profiles down to 100 m depth. Transitions from colluvium to bedrock were identified at 45 m and 80 m, dipping 12°–16° westward. Vs profiles align well with borehole and geological data.
