Figure 1 shows a 2-D shot gather in the study area. The hyperbolic water-table reflector is clearly visible at 20 ms traveltime. Unfortunately the very shallow reflectors in the sand above the water-table only appear on the near offset traces, as they are masked by the direct arrival and the water-table refraction at larger offsets.
Figure 1 2-D shot gather in the study area.
The water-table itself is only 2-3 m below the surface, so shallower reflections are not visible on offsets greater than about 3 m. The desire to record useful information on all sixty of the available channels, and physical limitations due to the size of the geophones forced us into a 3-D geometry. Moving to 3-D also gives us the potential to image structures that are not usually visible with conventional 2-D geometries.
As an aside, the full 3-D dataset is less than 220 Mb in size, and so provides an excellent test bed for SEP's in-house processing system, SEPlib3D.