Geophysics in Kamloops encompasses a suite of non-invasive subsurface investigation methods that measure physical properties of soil, rock and groundwater without excavation. These techniques are essential for understanding ground conditions across the Thompson Valley, where complex glacial deposits and variable bedrock depths create challenging site conditions. By deploying MASW / VS30 (shear wave velocity) profiling and seismic tomography (refraction/reflection), geophysicists can map stratigraphy, identify hazards and determine engineering parameters critical for safe design.
Kamloops sits within a geologically diverse corridor shaped by Pleistocene glaciation, lacustrine sedimentation and ongoing fluvial processes. The area features thick sequences of glacial till, glaciofluvial sands and gravels, and glaciolacustrine silts and clays overlying bedrock that ranges from Tertiary volcanic rocks to metamorphic assemblages. These deposits exhibit sharp lateral and vertical variations that can mask buried channels, soft clay lenses or potential liquefiable layers. Geophysical surveys bridge the gap between sparse borehole data, providing continuous profiles that reveal the true complexity of the subsurface.
Canadian geophysical practice follows the National Building Code of Canada (NBC) and the Canadian Foundation Engineering Manual, with seismic site classification per NBCC 2020 requiring shear wave velocity measurements in the upper 30 metres. British Columbia's Building Code and local City of Kamloops bylaws further mandate site-specific seismic hazard assessments for major structures. Professional practice is governed by Engineers and Geoscientists BC (EGBC), which requires qualified geophysicists to design surveys, process data and interpret results in accordance with ASTM and Canadian Geotechnical Society guidelines.
These services are critical for infrastructure and building projects across Kamloops, from highway bridges spanning the Thompson River to commercial developments on benchlands and institutional buildings in the downtown core. MASW / VS30 surveys are routinely used to classify seismic site response for schools, hospitals and multi-storey structures. Seismic tomography supports foundation design by mapping rippability, bedrock depth and fracture zones. Linear infrastructure such as pipelines and transmission lines also benefits from continuous geophysical profiling in this terrain of buried valleys and variable overburden.
Engineering geophysics uses surface-based instruments to measure subsurface physical properties like seismic velocity, electrical resistivity or density without disturbing the ground. In Kamloops, it is applied to map buried glacial deposits, locate bedrock, assess soil stiffness for seismic site classification and detect potential hazards such as soft clay layers or voids prior to construction.
Multichannel Analysis of Surface Waves (MASW) is the standard method for measuring shear wave velocity profiles to determine VS30, the parameter used by the National Building Code of Canada for seismic site classification. Seismic refraction tomography also provides P-wave and S-wave velocity models that complement MASW data for deeper or more complex geological settings.
Geophysical work falls under the professional practice requirements of Engineers and Geoscientists BC (EGBC). Seismic site classification must follow NBCC 2020 and BC Building Code provisions. The City of Kamloops may require geophysical reports as part of development permit applications, particularly for steep slopes, floodplains or areas with known geological constraints.
Geophysical surveys are recommended when borehole spacing is insufficient to characterize lateral variability, when access constraints limit drilling, or when seismic site class must be determined for structural design. Projects on variable glacial terrain, near river corridors or involving deep excavations and critical infrastructure typically benefit from early-stage geophysical input.