In Coventry, many site investigations hit an unexpected hard band of Mercia Mudstone or superficial glacial till that masks deeper bedrock, making standard borehole logs unreliable for foundation design. Seismic tomography resolves this by generating a 2D or 3D velocity model of the subsurface, distinguishing between weathered rock, stiff clay, and massive sandstone. Before committing to deep foundations or basement excavation, the team cross-references these velocity profiles with ground-truth data from an ensayo SPT to calibrate stiffness parameters. The method works particularly well across the city's variable drift deposits, where lateral changes in seismic velocity can indicate buried channels or solution features inherited from the Carboniferous limestone underneath. For a typical 15-storey residential block near the ring road, the survey covers a 200-metre line with 48 geophones spaced at 2 metres, producing a ray-path density that resolves anomalies down to 2-metre diameter.
Seismic tomography in Coventry delivers continuous velocity profiles that expose buried channels and rockhead variations, reducing borehole requirements by up to 40 percent.