Seismic Surveys

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NAEVA performs seismic refraction surveys to characterize subsurface geologic conditions. Using a spread of geophones, and a seismic impact source, the travel time for a wave to pass through a layer to another, refract along the interface, and return to the geophones at the surface is measured. The seismograph digitally records and stores the measurements for each field record. Data is subsequently processed and analyzed to make determinations.

Some applications of seismic refraction:

• Bedrock depth and topography
• Resolving strata and aquifer thickness
• Measuring overburden thickness
• Rippability calculations
• Engineering properties