This paper describes the application and numerical formulation of a state-of-the-art coupled computational fluid dynamics (CFD) and computational structural dynamics (CSD) methodology to the simulation of buried explosives inside of concrete or rock. Comparison of a typical cap rock model, with a more complex three yield surface one will be shown. Over the last several years we have developed a numerical methodology that couples state-of-the-art CFD and CSD methodologies. The flow code solves the time-dependent, compressible Euler and Reynolds-Averaged Navier-Stokes equations on an unstructured mesh of tetrahedral elements. The CSD code solves the large deformation, large strain formulation dynamic equations on an unstructured grid composed of bricks and tetrahedral elements, and uses VMS (variational multi-scale) stabilization to improve the robustness and stability of the numerical solution. The codes are coupled via a ‘loose coupling’ approach which decouples the CFD and CSD sets of equations, and uses projection methods to transfer interface information between the CFD and CSD domains. Both codes are parallelized using a distributed memory technique (MPI): The flow and solid domains are divided in several sub-domains which communicates through their respective inter-domain points. Also, the solution on each sub-domain uses share-memory parallelization (OpenMP "loop" parallelization). The final presentation will describe in detail the implementation of the concrete and/or rock fracture, and contact algorithm for the mentioned MPI/OpenMP parallelization scheme, which allows spectacular simulation speed-up for real life applications. In the final presentation, it will be shown that the results of a real-life simulation compares well with experimental data for the complex three yield surface model. The crater size generated by rock/concrete buried explosives agree very well with real tests. Spallation effects are reasonably captured too. Instead, although simple cap models reproduce the cratering effects, they are not able to capture the spallation ones.