Effect of smoothing radius on refraction statics corrections in hard rock terrains

Abstract

The sensitivity of refraction statics to choice of smoothing radius has been investigated for a deep crustal seismic line across part of the Lachlan Fold Belt. The effective smoothing radius depends on the size of the Fresnel zone for the refractor and we demonstrate that choice of smoothing radius is critical to the quality of the final stack where the refractor varies rapidly along the line. If too severe a smoothing is carried out, the quality of the final stack is severely degraded, although it can be partially recovered with automatic residual statics. In this case, automatic statics calculated for a deep gate between 3 and 5 s TWT were able to sharpen features in the upper 2 s. However, the implications for areas without good reflector continuity is that determination of the optimum smoothing in calculation of refraction statics is crucial.