The International Building Code, as adopted by Newark, places a clear responsibility on the geotechnical engineer to characterize subsurface conditions before foundation design begins. In a city where 250-year-old brick sewers share space with brownfield parcels and buried estuarine clay, relying on a handful of boreholes leaves dangerous blind spots. The electrical resistivity / VES (vertical electrical sounding) method fills those gaps. By injecting a known current into the ground and measuring the resulting potential difference, the equipment maps how easily the soil transmits electricity. That property, resistivity, shifts dramatically between dry sand, saturated silt, saltwater-influenced clay, and hydrocarbon contamination. Newark's location along the Passaic River and Newark Bay means the water table sits high, and saline intrusion isn't theoretical, it shows up in the data. The survey delivers a continuous profile of subsurface layering, which helps the design team position additional SPT drilling exactly where the geophysics indicates a transition, not where the grid says a boring should go.
In Newark's brownfield corridors, resistivity soundings often catch a sharp conductivity spike at the fill-native interface that conventional borings miss entirely.
