This document tries to define and analyse a method in the approach to study Tunnels under seismic condition, trying to establish if the application of a simple methodology provides plausible results and if they are of aid for the planner’s time optimization. Furthermore, the present report, tries to demonstrate how the seismic loads, combined like the definition in the limit states, involve redefining the classical method of structural dimensioning. We will see with the assistance of the advanced numerical model, for example finite elements, are fundamental and of an importance to determine the stress inside the final lining and the simple analysis, also if fast and convenient, are not real. Furthermore the new laws for the construction, D.M. 14 January 2008, states that all structures must be planned to allow a longer duration, foreseen just in the plan phases, coherent with the safety degree foreseen of laws. In particular the structures have to warranty to the safety of the Final Limit States and Operating Limit States respectively and finally warranty the safety to exceptional actions. To perform this different analysis we have suppose some rock parameters, this values are conservative and we are reminded that this study has academic valence and that it is direct to make comparisons between different methods. In case of subsurface structures over the usual loads it is necessary define the seismic action, which depends on the type of analysis that will be performed. The support in the Tunnel, we know, can be modelled like an arch subjected to ground loads that it must sustain. Therefore the structure develops on the height, over to be underground, and it is subject on its base to shear wave, secondary seismic wave, resulting from geological causes. We must remember, being the norm-oriented after the partial safety coefficients, that the material strength must also be multiplied for the respectively coefficient, particularly “M1” for the ground and the normal reduction factor for the structurally material like steel and concrete. In the case of seismic analysis the calculation code performs a different analysis with the aims of: – comparison between the obtained results and a dynamics analysis in FEM-2D; – the correct method choice to optimize the required time; The implementation methods are: – equivalent static method through the definition of horizontal forces; – equivalent static method through the active side pressure; – dynamic equivalent modal analysis. Furthermore will be performed a Dynamics analysis with 2D-FEM. After all calculation it is possible to conclude that the traditional seismic analysis, also knows as equivalent static, leads to results not in real terms of displacements and forces, due to fictitious simulation through the use of springs, soil, and loads, see Bieniawski. While a dynamics modal equivalent analysis in 1D leads to certain equivalence in terms of normal forces but not for the bending moments. This effect is due to the elastic constant value which is too rigid and also for the fixities at the foot of the Tunnel lining. From the verification point of view it is interesting to note, as in the example, the distribution of M-N values, in the 2D dynamics analysis, that is inside the break space of the section and that in case of an earthquake reinforced steel is not necessary for this example. Naturally this result cannot be generalized for each structure and each boundary condition. We can conclude that for a correct estimation of displacements and forces it is necessary to use advanced numerical analysis in two, and if possible in three dimension, because the 1D geometry for the lining involves the assumption of empirical loads that don’t fully describe the action, static and dynamics, in the structures.