Tomostatics entails deriving a near surface velocity model via turning ray tomography, then computing the associated static corrections.

The output velocity (actually slowness) model is parameterized on a 2D or 3D grid (i.e., rather than via a series of discrete layers as in the GLI case), and experience has shown that it can produce a better statics solution than that obtained by the GLI algorithm in cases where the near-surface geology departs significantly from layer-cake. TGS uses the industry-leading GeoTomo 3rd party software for its 2D and 3D tomostatics applications. The algorithm differs from conventional tomostatics implementations in its use of a nonlinear, rather than linear, inversion kernel, thereby providing relative insensitivity of the final result with respect to starting model. In addition to the tomostatics algorithmic engine, the software features many powerful QC tools for examining first break reliability, establishing the initial model, visualizing the final tomostatics output model, and picking the model base prior to replacement statics computation.