Benefits of Correcting for Vibrator-Earth Coupling Variation

Along a seismic line the coupling of the vibrator to the ground is generally variable.<br>This is particularly true in case of loose, weathered ground condition. If this variation<br>is not accounted for during raw vibrogram compression, the effective source wavelet<br>in the seismic data becomes variable. This has a negative implication on both imaging<br>and characterization results. To correct for the vibrator-earth coupling variations at<br>different source locations, one needs to be able to measure the source motion for the<br>entire (or at least for a large part of the) frequency bandwidth of the sweep. For large<br>vibrators, a reliable measurement is not a simple task because of the large force, the<br>limited rigidity of the vibrator baseplate, and the nonlinear near-field deformation.<br>However, in the recent years, new developments that try to address these issues have<br>been reported.