The ground conditions between Matapihi and Bethlehem can shift dramatically over just a few hundred metres. On the harbour side, you often encounter soft estuarine silts and high groundwater, while moving inland toward the Kaimai foothills reveals layers of volcanic ash and ignimbrite. This variability makes a single borehole insufficient for site characterization. We apply electrical resistivity and VES surveys to map these transitions continuously across a site. The method measures how soil and rock resist current flow, which changes with porosity, saturation, and clay content. For Tauranga’s mix of pumiceous sands and underlying rhyolite, we often pair resistivity lines with a CPT test to tie geophysical signatures to direct penetration data, giving you a defensible ground model before any earthworks begin.
Resistivity gives us a continuous profile where boreholes only provide points—critical when mapping paleochannels or ash layers that shift laterally beneath Tauranga.
