The Thompson Valley's sharp winter-to-summer range, from -20°C frost to 35°C dry heat, shifts near-surface stiffness month by month in Kamloops. That seasonal swing changes shear wave velocity, which means a VS30 measurement taken in frozen February looks nothing like one in August. Our field crew runs MASW lines on glacial lakebed silts and compacted till across Kamloops neighborhoods to pin down the true dynamic soil behavior—not just a snapshot. We pair the dispersion output with SPT drilling data where sand layers or cobble-rich units demand a combined view, and we cross-check against seismic refraction profiles when bedrock depth is uncertain near the valley margins.
A reliable VS30 in Kamloops requires a dispersion curve that works down to 4-6 Hz—anything shallower misses the deep silt signature.
