It is well-known that a lot of standard processing procedures become useless in case of heterogeneous upper part, complex surface and strong variations of datum.
Layer reconstruction is powerful tool for approximation of complex strata, such as salt domes or permafrost. Approximation is insertion of one or several local-homogeneous layers consequently to the originally single heterogeneous upper layer. Some information about depths of deeper horizon is required to make reconstruction. In case we know position or configuration of deeper horizon, we can fix it and create some intermediate horizons in the upper area.