Seismic design of sensitive structures requires the characterisation of the ground motion at the surface.  GEODECO investigates the response of the soil deposit by means of truly-nonlinear-dynamic finite element analyses of the soil column subject to real rock ground motion recordings. The procedure is formulated on the basis of effective stress principle, vector motion, transient pore fluid movement and generalised material stiffness. The multi-directional formulation and the use of advanced plasticity models for soil behaviour allow handling of shear wave and compression wave simultaneously.  GEODECO can perform liquefaction analyses in the time domain, using truly non-linear software. Our methodology considers the effects of soil non-linearity and of soil-fluid interaction to probabilistically predict the hazard of cyclic mobility and liquefaction at any relevant depth.  GEODECO provides consulting for the selection of suitable liquefaction-mitigation methods.