The processing sequence includes amplitude recovery, spectrum equalization from 12–160 Hz, wave separation by SVD and F-K filters.

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  Step 1: Amplitude recovery and F-K diagram.
  The data are displayed both in the time distance domain and in the F-K domain. In the F-K diagram, the horizontal axis is the reduced wavenumber.


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  Step 2: Amplitude recovery reciprocal shots


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  Step 3: Extraction of Refracted wave by SVD and F-K diagram.
  The complete wave-separation procedure used to attenuate coherent noise is performed on shot records in two parts. In the first part, direct and refracted waves are removed using a SVD filter, after spectrum equalization. To optimize the procedure, the direct and refracted arrivals are flattened prior to SVD so that they have infinite apparent velocity. The time-shifts used to flatten these events are obtained from the first arrival times picked for refraction analysis.


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  Step 4: Reciprocal shots - Extraction of Refracted wave by SVD


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  Step 5: Extraction of Surface waves by F-K filter and F-K diagram.
  In the second step, pseudo- Rayleigh surface waves (low apparent velocity waves) are removed from the residual record using a FK filter. Similar to the SVD filtering procedure, the FK filter is used to extract a model of the low velocity waves.


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  Step 6: Reciprocal shots - Extraction of Surface waves by F-K filter


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  Step 7: Residual section and F-K diagram.
  The model is subtracted from the residual record obtained from SVD filtering to obtain a final residual record that clearly shows high apparent velocity events that are associated with reflected waves


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  Step 8: Reciprocal shots -Residual sections