M.S. Howard, S.H. Danbom, 1983. "Random Noise Example", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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Figure 1 (left) is a common-shot-point gather of synthetically made seismic traces using a random number generator. These data would represent the zero end point of the signal-to-noise ratio spectrum -a ratio commonly used to measure the reflection signal strength as compared to random ambient noise. Figure 2 (center) is a final stacked section made from a collection of these random field files. The processing sequence that resulted in this figure is common to the industry (elevation static corrections, sort to common-depth-point gathers, normal velocity moveout corrections, etc.). These data will necessarily still be random, but an interpreter who is extremely hardened to working in poor record areas may see some chance alignments in this display. Perhaps this can be more clearly seen by viewing the section obliquely.
Figure 3 (right) results when these final stacked traces are mathematically manipulated by a new modern processing technique. In essence, this figure results when severe trace mixing is the end result of a process that is more sophisticated at face value. Here, the chance alignment is enhanced by the mixing process. Whereas this particular method would not be misused by the scrupulous processing geophysicist, Figure 3 should alert anyone who commonly works with seismic data in poor record areas to the possible dangers of signal enhancement beyond reasonable limits.