GPR is a noninvasive way to image the shallow subsurface using electromagnetic waves which rebound off subsurface reflectors.
A 700m shore perpendicular GPR transect across the Grand Island Tombolo used a pulseEKKO 100 GPR system with 100 MHz antennae. Data collection used a step size of 0.5m and antennae separation of 1.0m. A topographic survey, using a Topcon RL-H3CL laser level, was also conducted to adjust profiles to changes in relief.
A common midpoint survey indicated the velocity of the electromagnetic wave through the sediment to be 0.1 m/ns. Profiles were processed with pulseEKKO software utilizing trace-to-trace averaging, down-the-trace averaging, dewow and automatic gain control and plotted using wiggle trace formatting.