This study deals with the effect of the FE mesh geometry on the localization phenomena and the use of a regularization method is evaluated for the analysis of shear bands under dynamic conditions. The regularization method used, called first gradient of dilation method, proposes an enriched kinematic approach for a medium and aims to eliminate the mesh dependency of the results. A parametric analysis, using different values of regularization parameters is perfomed and the results demonstrate that the first gradient of dilation regularizing method should be enhanced to deal with dynamic problems on softening soil materials.