In St. John's, many of the older neighborhoods sit on a thin veneer of glacial till draped over steeply dipping Ordovician shales and sandstones. You see it clearly during excavation on the Southside Hills—what looks like solid ground can mask a highly variable bedrock surface just a few meters down. We rely on electrical resistivity testing and VES to map that hidden interface without poking dozens of boreholes. The marine clay pockets in the Waterford Valley also show a distinct low-resistivity signature, which helps us delineate compressible zones before foundation design begins. For deeper infrastructure, like the buried utilities along Kenmount Road, a seismic refraction survey sometimes complements the resistivity lines when we need both a velocity model and a resistivity profile to confirm weathered versus competent rock.
Resistivity profiling in St. John’s provides a non-invasive way to map bedrock depth and saline water boundaries, two of the most common geotechnical concerns across the Avalon Peninsula.
