Results and conclusions

Analysis of the super-gather shown in Figure 5, suggests the higher effective fold at near offsets (compared to 2-D experiments) leads to improved vertical resolution in the very near surface. Hyperbolic reflection events are clearly visible above the water-table reflector. Additionally, the frequency content of the data is sufficiently high to see that what appeared to be the water-table reflector at lower frequencies is in fact two distinct events of positive polarity separated by about 4 ms ($\approx$ 50 cm).

Unfortunately, the low signal-to-noise ratio makes it difficult to resolve 3-D structure on the water-table or the weaker reflectors both above and below it. Figure 7 shows the stacked 3-D data, stacked again in the X and Y directions. There does indeed appear to be a small amount of structure in the X direction (perpendicular to the shoreline). This is also apparent on the timeslice shown in Figure 8. It is unlikely to be an artifact of the acquisition geometry or processing, since the feature is not symmetric in the X=Y plane.