cancel random noise but their main function, I believe, is to cancel low-velocity coherent noises, something we now see is handled effectively by steep-dip deconvolution. While I do not advocate abandoning field arrays, it is pleasing to notice that with the arrival of steep-dip deconvolution, we are no longer so dependent on field arrays and perhaps coherent noises can be controlled where field arrays are impractical, as in certain 3-D geometries. A recently arrived 3-D shot profile from the sand dunes in the Middle East is Figure 11. The strong hyperbolas are ground roll seen in a line that does not include the shot. The open question here is, how should we formulate the problem of ground-roll removal in 3-D?
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