SUMMARY We outline a number of algorithms that can be used for the THIN SHEET MODELS interpretation of 3-D electromagnetic data. The algorithms A thin sheet model consists of one or several horizontal, differ by the type of the electromagnetic data to be conductive and/or resistive thin inhomogeneous layers interpreted and the geological situation in the area of embedded in a stratified structure (Figure 1). Each algorithm is based on a thin-sheet model. Each model comprises one or several A conductive thin-sheet (S-layer) is described by an inhomogeneous layers and an embedding 1-D medium. INTRODUCTION A traditional inversion algorithm includes a modelling where and are depth levels corresponding to the component calculating the electromagnetic field in a top and bottom of the inhomogeneous layer, respectively. It also includes an optimization Thus, is the layer thickness.