Figure 4 shows that much of the wave field has been removed, leaving mostly random noise and a one particularly coherent event. This is a good result if that remaining strong event is a reflector, and if no other reflectors that should be present have been removed. The location in time of the event fits the expected location of a prominent geologic interface in the area, which is a conglomerate over a mudstone. The event is fairly shallow and dies out at near offset, which should make one strongly suspicious that it is actually a refraction and not a reflection that has been preserved. However, the interface is a negative velocity contrast so one should not expect to see energy refracting along it from above. Also, because it is fairly high frequency and does not reverberate for many cycles, it does not have the typical character of a refraction.
It is suspicious that the amplitude dies so strongly at near offset, but this could simply be due to the geophone response being swamped by the high amplitude of the ground roll at short time. It is very suspicious that the event is in phase with the ground roll, although this would be expected of a real reflection in this particular setting.
The only other reflector that might be expected is the bottom of the mudstone. Standard processing of lines in this area generally failed to image the bottom of the mudstone, so it is not surprising that it is not there.