Spectral Element Method has convincingly demonstrated the ability to handle high-resolution simulations of seismic wave propagation in 3D complex domains. However, the exponential accuracy of the method and the reduction of the computational effort rely on the use of conformal hexahedral meshes. Generating an all-hexahedral mesh based upon the available meshing can be difficult. We propose to use a 3D unstructured tetrahedral mesh generator and then split the resulting mesh into hexahedral elements. This approach allows using the same modeling SEM program without any modifications, and it remains faster than dealing with tetrahedral spectral element due to the tensorisation property for spatial derivatives. With this approach, the SEM method doesn't have restrictions to solving complex problems in sonic or seismic data with respect to methods using tetrahedral meshes. Two examples dealing, respectively, with sonic-modeling and the other with surface seismic modeling illustrate the feasibility of the proposed method.