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Ground-Penetrating Radar can be used to map man-made features, such as tanks, drums or infrastructure; or variations in soil or bedrock, such as stratigraphic changes or voids. Ground-Penetrating Radar provides a continuous profile of the subsurface by transmitting a radio frequency signal into the ground through an antenna as it is moved along the surface, then measuring variations in the reflected radar waves. Shallow subsurface materials with contrasting electrical properties, such as a drum/soil interface or bedrock/soil contact, are often apparent in GPR cross-sectional profiles.
The advantage of a Magnetometry survey is its extreme sensitivity to the presence of buried ferrous materials, such as steel drums, tanks, vehicles, piping or other infrastructure. Magnetometer screening can be done at a walking pace on open land, making this technique relatively cost effective.
This technique measures the electrical conductivity of subsurface soil and bedrock, and is sensitive to ferrous and non-ferrous materials. Often used for detection of buried drums, tanks and infrastructure, EM techniques can also be used to detect contaminant plumes, determine lithology, and identify the margin of landfills.
Contaminant plumes, burial sites, and geohydrologic conditions can be inferred by mapping lateral changes in subsurface electrical properties via DC resistivity “soundings.
Seismic Refraction techniques can be used to determine the depth and thickness of geologic strata. When used in conjunction with soil boring and well data, seismic measurements can allow extrapolation over a larger area, reducing the cost of boring programs and monitoring well networks. Seismic waves induced at the surface travel downward and are bent or “refracted” at the interface of differing layers. By using an array of geophones to measure the wave travel time, we infer the seismic velocity of each layer, which is directly related to its properties, such as density and hardness.
