2D and 3D refraction statics via tomographic inversion with under-relaxation

The computation of refraction static corrections is a difficult but important step towards obtaining reliable seismic stacked sections, particularly with land data. The difficulty lies in the high degree of variability of thickness and velocity of near surface layers. The importance lies in the fact that if subsequent processing tools such as velocity analysis, residual reflection statics and migration are to perform optimally it is imperative to first resolve the major sta tics problems using refraction techniques capable of broadband solutions.