The National Building Code of Canada (NBCC) now makes seismic site classification a mandatory step for most structural projects, and St. Catharines sits in a unique geological position where the buried bedrock of the Niagara Escarpment interacts with thick glacial and lacustrine sediments, creating sharp velocity contrasts that demand a non-invasive approach like MASW. Surface wave testing gives engineers the Vs30 value they need to assign a Site Class—whether it's C, D, or E—without mobilizing a drill rig on day one. Across the Garden City, from the Twelve Mile Creek valley to the lowlands near Lake Ontario, the shear wave velocity profile can shift dramatically over short distances, and getting it wrong has real consequences for foundation design. Our field crew runs active-source and passive-source MASW arrays calibrated to ASTM D5777 and D7400, delivering dispersion curves and 1D Vs profiles that the structural engineer plugs directly into the seismic analysis. For deeper targets where the bedrock might be 30 meters down or more, we often pair the survey with a few SPT boreholes to correlate the dynamic properties with standard penetration resistance, giving the geotechnical report a level of redundancy that plan reviewers appreciate.
In St. Catharines, MASW doesn't just give you a Vs30 number—it reveals where the Escarpment bedrock drops, and that changes everything about seismic demand.
