Modelling studies have shown that the ratio of incident angles for P-SV and P-P reflections is about 1.3 for a common receiver location. This means that for a given source-receiver offset, pre-critical P-P reflections may be recorded with post-critical PSV reflections. This has serious implications for the P-SV stack, which requires that the phase for all reflections in the gather be stationary if the integrity of the stack is to be maintained. Long source-receiver offsets for P-SV acquisition are therefore not recommended. This requires that a major effort in multicomponent surface seismic data acquisition must be directed at attenuating source-generated noise and extracting useable reflection signal in the mid-offset range.
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