We set up a portable three-component seismometer directly on the ground surface in Drummondville. No drilling, no heavy machinery — just a compact sensor that records ambient vibrations for 30 to 60 minutes per station. The equipment captures horizontal-to-vertical spectral ratios (HVSR) to identify the fundamental resonance frequency of the soil column. This non-invasive method works exceptionally well in Drummondville's glacial till and alluvial deposits overlying the St. Lawrence Lowlands bedrock. Before running the survey, we often cross-reference results with a MASW survey to obtain vs30/" data-interlink="1">shear wave velocity profiles, or integrate data from a dilatometer test for deeper stratigraphic detail. The whole field campaign typically takes one to two days for a standard residential lot.
A 2 Hz soil resonance in Drummondville's clay basins can amplify seismic waves by a factor of three — HVSR catches that risk before the design is locked.