Strike versus dip shooting

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Seismic Data Analysis
Series Investigations in Geophysics
Author Öz Yilmaz
ISBN ISBN 978-1-56080-094-1
Store SEG Online Store

It is interesting to raise the question of which direction is better in recording — dip line or strike line, since we just noted that crossline smearing is most severe when shooting in the strike direction. Both types have advantages and disadvantages.

Aspects of dip-line shooting are summarized below:

  1. With dip-line shooting, you have a better spatial sampling in the direction that you need most.
  2. Since there is no cross-dip, there is no crossline smearing, and you can afford coarser spacing between lines.
  3. With dip-line shooting, you have the disadvantage of complex moveout on common-cell data that can cause problems in velocity analysis [1].
  4. You also have the problem of inline smear because of the reflection point dispersal along the dipping reflector associated with a nonzero-offset recording (Section E.1). Nevertheless, DMO correction handles this problem.

Aspects of strike-line shooting are summarized below:

  1. With strike-line shooting, you have better attenuation of coherent noise because of the moveout behavior of side scatterers.
  2. Since there is no dip perceived on a strike line, in principle, you do not need DMO correction.
  3. With strike-line shooting, however, you have the disadvantage of perceiving the largest cross-dip, hence you would have the problem of crossline smear to deal with.
  4. More importantly, strike-line shooting would require closer line spacing to prevent spatial aliasing of steep dips in the orthogonal direction; otherwise trace interpolation becomes important.

Among these various factors, adequate spatial sampling of steep dips is a requirement that takes precedence over the others. This means that, given the choice between the two types of shooting, dip-line shooting must be employed almost always in data acquisition. Nevertheless, modern 3-D surveys are conducted using sufficiently small inline and crossline spacings which more than accommodate the requirements for adequate spatial sampling of steep dips, minimizing crossline smearing and accurate implementation of 3-D DMO correction for removing inline smearing.


  1. Larner and Ng, 1984, Larner, K. and Ng, P., 1984, Strike versus dip shooting: 53th Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 256–260.

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Strike versus dip shooting
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