MASW / VS30 Testing in Drummondville – Shear Wave Velocity Sur…

The difference is striking: in Saint-Nicéphore, the glacial till deposits yield moderate shear wave velocities around 350 m/s, while near the Saint-François River, soft alluvial sediments drop below 200 m/s. That contrast drives everything in foundation design and seismic response. A MASW survey across Drummondville captures these velocity profiles without drilling a single hole. We combine surface wave analysis with field verification to map Vs30 values across your site. Before we deploy the geophone array, we often recommend a calicatas exploratorias to correlate surface velocities with actual soil stratigraphy. This integrated approach gives you a reliable base for seismic site classification under NBCC and ASCE 7.

Illustrative image of MASW / VS30 (shear wave velocity) in Drummondville

A single MASW line can replace multiple boreholes for seismic classification, saving time and reducing site disturbance in Drummondville.

Our service areas

Ground improvement

Unsaturated soil analysis ›Stone column design ›Dynamic compaction design ›Deep Soil Mixing (DSM) design ›Geotechnical drainage design ›

VIEW ALL GROUND IMPROVEMENT ›

Slopes & Walls

Soil erosion analysis ›Slope stability analysis ›Slope failure analysis ›Debris flow analysis ›Factor of safety (FS) calculation ›

VIEW ALL SLOPES & WALLS ›

Foundations

Differential settlement analysis ›Settlement analysis ›Bearing capacity analysis ›Foundations on fill (analysis) ›Shallow foundation design ›

VIEW ALL FOUNDATIONS ›

Methodology and scope

Drummondville sits at roughly 95 m above sea level, with a bedrock depth that varies from 5 m in the north to over 30 m in the southern floodplains. That variability demands a method that can profile large areas quickly. MASW uses a 24-channel geophone spread and a sledgehammer or vibroseis source to generate Rayleigh waves. We then invert the dispersion curve to obtain a 1D shear wave velocity profile down to 30 m or deeper. The resulting Vs30 value determines the NEHRP site class (A through F), which directly affects your building code requirements. Pairing MASW with ensayo SPT at key locations improves the correlation between velocity and penetration resistance. This dual approach is common in Drummondville because the glacial till layers are often dense enough to mask softer interbeds.

Technical reference — Drummondville

Local considerations

The equipment setup is straightforward: we lay out a 24-geophone cable along a straight line, each geophone coupled firmly to the ground. In Drummondville's agricultural fields, that means clearing a thin layer of topsoil to ensure good contact. On frozen ground, we use a hammer drill to set the spikes. We then strike a steel plate with the sledgehammer at each end of the array. The data acquisition system records 10 to 15 blows per shot, stacking them to improve signal-to-noise ratio. Any nearby traffic or machinery can contaminate the record, so we coordinate with your site crew to minimize interference during the test window.

Need a geotechnical assessment?

Reply within 24h.

Email: contact@geotechnical-engineering.org

Applicable standards

ASTM D4428, NEHRP (BSSC 2020), ASCE 7-22 (site class), NBCC 2020 (seismic provisions)

Technical parameters

Parameter	Typical value
Vs30 range for site class C	360–760 m/s
Vs30 range for site class D	180–360 m/s
Max profile depth (standard)	30 m
Number of receiver channels	24
Source type	Sledgehammer (8 kg) or vibroseis
Field time per 100 m line	Approx. 2–3 hours

Frequently asked questions

What is Vs30 and why does it matter for my project in Drummondville?

Vs30 is the average shear wave velocity in the top 30 meters of soil. It determines the NEHRP site class, which controls the seismic design spectrum. For example, a site class C (Vs30 360–760 m/s) requires a different base shear than a site class D (180–360 m/s). Using MASW to obtain Vs30 avoids the uncertainty of guessing the site class from surface geology alone.

How deep does a MASW survey typically reach in Drummondville soils?

With a 24-channel array and 2 m spacing, we achieve reliable inversion down to 30 m. In areas with soft alluvial deposits (e.g., near the river), the depth may extend to 35 m. On stiff glacial till, the resolution remains good to 25–30 m. If deeper profiling is needed, we can increase the array length or use a lower-frequency source.

How much does a MASW survey cost in Drummondville?

A single-line MASW survey typically ranges between CA$2,380 and CA$4,920, depending on site access, line length, and number of shot points. Multi-line 2D surveys start at the upper end of that range. Contact us for a firm quote based on your specific layout and access conditions.

Do I need a MASW survey if I already have SPT borings?

MASW provides continuous velocity information between boreholes, which SPT cannot. If your site has variable soil conditions (e.g., pockets of soft clay within till), MASW will identify those zones. The combination of SPT and MASW gives you both soil classification and velocity data, which strengthens the seismic site classification and can reduce the number of required borings.

Location and service area

We serve projects across Drummondville.

Location and service area