Second seismic image

The second seismic test case, shown in Figure 9 depicts a fault-bounded North Sea horst structure. Figure 11 shows a plane view of the the selected time and vertical image slices.

 

nseaFoltTotRawVol Figure 9 Volume view of North Sea horst. The Figure represents a volumetric view of the sections of the previous Figure 11. The mid-volume lines indicate the position of the extracted and displayed two-dimensional sections.

The vertical sections show sets of parallel listric faults that flank a complex horst structure. Except at the northern edge of the image, the sediments are nearly horizontal. The lower fault blocks are, however, slightly tilted, which undulates the upper sediments. In contrast to the vertical section's listric faults, the time slices' intricate zigzag and rhomboidal fault pattern is difficult to discern and indicates the three-dimensional complexity of the entire horst region. The vertical sections of Figure 11 show listric faults: their dip decreases with depth. However, the faults do not sharply cut the surrounding sediments but, rather, seem to interpolate between them. As illustrated in Figure 10, the images faults show a width of a few samples and their spatial frequency components do not show much energy above half-Nyquist.

 

nseaFoltFltRaw
Figure 10 North Sea horst fault and its trace spectrum. The image detail on the left isolates a typical listric fault of the North Sea horst image. The averaged trace spectrum on the right demonstrates the rather low-frequency contents of the fault image.

I expect a successful discontinuity map to delineate the complex fault pattern of the horst's time slice. Furthermore, I expect the sedimentary layers in the vertical sections to be removed. Bednar  tested his discontinuity attribute at this image. To facilitate a comparison among this chapter's discontinuity attributes, I marked a major fault in Figure 11 with an F.

 

nseaFoltTotRaw
Figure 11 North Sea horst image. The time slice depicts a fault-bounded horst structure and indicates an intricate fault pattern.

 

nseaFoltTotMrk
Figure 12 Annotated North Sea horst image. F marks a listric normal fault that is barely visible in the time slice, but that is well visible in the in-line section.