EFFECT OF SUBSURFACE SAMPLING ON ONE-DIMENSIONAL SYNTHETIC SEISMOGRAMS

In generating one-dimensional (1-D) synthetic seismograms from sonic and density logs, the actual sub-surface is replaced by a sequence of beds so constructed that the time required to traverse each bed is the same. Since Wuenschel (1960) devised the method, geophysicists have assumed that as long as the beds were thin, ie. subsurface time sampling was fine enough to avoid aliasing in the source waveform, the synthetic seismograms would be independent to be unjustified. Even when the subsurface is sampled more than twice per period at the maximum source frequency, the traces generated by a synthetic seismogram program may change as the sampling changes.-Authors