Recommendations

A 400V transmitter should be used to enhance GPR resolution in the shallow subsurface. This study used a 1000V transmitter, but 400V transmitters are also available for the pulseEKKO 100 system. The difference between the two voltages is displayed in the profiles below from Jockeys Ridge dune in North Carolina. The profile on the left was surveyed with a 1000V transmitter, and the one on the right used a 400V transmitter. Notice that the 1000V profile penetrates deeper into the ground, but there are fewer layers in each inch of the profile.
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In order to identify any changes in sea level indicated by beach ridge elevation through time, the GPR profiles must all be tied to actual elevation. Surveying to a bench mark would enable such correlation.

To avoid the difficulties caused by velocity differences in saturated and dry sand, separate transects should be performed on saturated and dry media. This will enable the appropriate velocity values to be applied to the dry and saturated portions of each profile.