Seismic Engineering

Geophysical Testing

Site specific geophysical data for geotechnical design applications.

Seismic Data Your Engineer Can Rely On

The BC Building Code and the National Building Code of Canada require seismic site classification for most new building permits in British Columbia. Site classification depends on the average shear wave velocity (Vs30) of the upper 30 metres of soil.

Coast Geotechnical measures Vs30 and determines seismic site class using multiple methods: Seismic CPT (SCPT), Multi-Channel Analysis of Surface Waves (MASW), downhole shear wave velocity testing, and SPT correlations within drilled boreholes. We have the equipment and in-house expertise for all of these approaches, allowing us to match the right method to your site conditions and project requirements.

Our reports document the testing methodology, data and interpreted results in a format accepted by BC municipalities and building officials.

Scope of Services

  • Seismic CPTu (shear and compression wave velocity)
  • Downhole Seismic Testing in PVC or sonic override casing
  • Multi-Channel Analysis of Surface Waves (MASW)
  • 2D seismic profiling (24 to 48 channel)
  • SPT-based Vs correlation in drilled boreholes
  • Seismic site classification (Vs30)
  • Liquefaction susceptibility screening
  • Modulus analysis
  • Seismic hazard assessment

How It Works

01

Project Review

We review your building type, structural system, and local seismic context to scope the appropriate testing program.

02

Field Testing

Shear wave velocity testing is conducted on-site, efficiently combined with CPT testing where possible to minimise mobilisation costs.

03

Site Classification Report

We deliver a sealed report with Vs30 values, site class designation, and any additional seismic parameters required.

Common Questions

Frequently Asked Questions

What is Vs30 and why does it matter? +
Vs30 is the time-averaged shear wave velocity of the upper 30 metres of a soil profile. It is the key parameter used by both the NBCC and BCBC to assign seismic site class, which determines seismic design loads applied to your building.
Is seismic site classification required for every building permit? +
Requirements vary by municipality, but seismic site classification is increasingly required for new construction in seismically active areas of BC. Particularly in Victoria, Nanaimo, and Metro Vancouver.
Can you combine Geophysical Testing with a standard CPT investigation? +
Yes. Our SCPT cone records shear wave velocity data alongside standard CPT measurements in a single push, eliminating the need for a separate testing mobilisation.