Drummondville sits on the St. Lawrence Lowlands, a region underlain by thick Champlain Sea clay deposits that can amplify seismic waves unpredictably. With a population exceeding 79,000 and growing, the city faces moderate seismic hazard from the Western Quebec Seismic Zone, where historical events like the 1944 Cornwall-Massena earthquake (magnitude 5.8) remind us that ground motion cannot be ignored. Our team has been performing site response analysis here for over a decade, and we consistently find that the deep clay layers shift the natural period of the soil column, which means standard code-based design spectra often underestimate the actual shaking at the surface. That is why we integrate field measurements, such as the [MASW survey](/masw-vs30/) for shear-wave velocity profiles, with laboratory resonant column tests to capture the stiffness degradation and damping characteristics specific to Drummondville's soils.
In Drummondville's deep clay, code-based spectra can miss the real amplification — site-specific analysis is the only reliable path.