Seismic Refraction & MASW for Geotechnical Surveys

Seismic refraction measures the travel time of seismic waves (usually P-waves) refracted at boundaries between layers of differing velocity. From this we derive layer depth and velocity — very useful for determining bedrock depth and ground stiffness for foundation, dam, and road projects.

MASW (Multichannel Analysis of Surface Waves) analyzes surface waves (Rayleigh waves) to produce a shear-wave velocity (Vs) profile versus depth. MASW is a non-invasive method commonly used to obtain Vs30 and assess seismic site response.

Use seismic refraction for bedrock-depth mapping and rippability (ease of excavation), and MASW for Vs profiling and seismic site classification. Both are often run together on the same geophone spread, making them efficient in the field.

You need a multi-channel seismograph such as the Geometrics Geode (global standard) or OYO McSEIS, geophones, and a seismic source (hammer/acquisition). The Geode supports both refraction and MASW with flexible channel counts for shallow-to-intermediate surveys.