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One focus of the Illinois Geological Survey involves the detailed study of aquifers and contamination from soil gas. A land streamer allows collection of enough data to map large areas quickly and efficiently.
Andre uses an impulsive source and finds that a simple hammer is often all that is needed to give data as deep as 1 second. The slower propagation speeds of shear waves yield improved resolution for characterization of lithology. In the seismic sections below, several lithologic units are visible. What is remarkable is evidence that this technique measures a sufficiently wide range of frequencies to detect culverts and bridge abutments close to the surface
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