Amplitude Calibration

After prestack migration and RNMO correction, the data need to be calibrated for the loss of amplitudes with offset. The use of 100 m group spacing at the near offsets and 50 m group spacing at the far offsets introduced a strong array attenuation at the central offsets of the data. The resulting loss in amplitude is clearly visible in Figure . Further loss in amplitude can be caused by different source strength and receiver gains, source array effects, transmission loss, attenuation, noise and so on. Ideally, these effects should be compensated for in a deterministic way, which would require the accurate calculation of the amplitude affecting components, assuming the different amplitude affecting processes are clearly separable. Very often, however, the accurate parameters are difficult to calculate or estimate.