Analysis of the acoustic seismic energy flux propagated through synthetic models formed by different structures

Abstract Seismic‐acoustic wavefield propagations on synthetic 2D models formed by different structural backgrounds are analysed in four test cases. These test cases were carried out employing staggered‐grid finite differences and absorbing boundaries of the convolutional perfectly matched layers type, which allowed analysing in a time of 7.0 s: (a) the seismic‐acoustic wavefield behaviour, (b) the kinetic seismic energy flux and potential seismic energy flux and (c) the energy differences (ΔKEF/ΔPEF) due to each type of proposed structure. In the first two test cases, a relationship was observed between average kinetic seismic energy flux/potential seismic energy flux values and the different structural densities ε of each synthetic model, which were formed by a similar type of structure (fractures). The average kinetic seismic energy flux values increased when ε decreased, whereas the average potential seismic energy flux values decreased when ε also decreased. The largest ΔKEF/ΔPEF values were observed for those models with more structures, reaching up to 0.2 × 108/0.21 × 108 J/m2 in the first test case and up to 1.95 × 108/1.91 × 108 J/m2 in the second test case. Meanwhile, for those models with less number of structures was 0.04 × 108/0 J/m2 in test case 1 and 0.26 × 108/0.61 × 108 J/m2 in test case 2. In the third test case, a relationship was observed between the average potential seismic energy flux values and the ε values, but not with the average kinetic seismic energy flux values, the synthetic models of which were formed by different types of structures (lobes and fractures under different shapes and sizes). The kinetic seismic energy fluxes were more affected by structures closer to each other than by those further apart. Meanwhile, the potential seismic energy fluxes were more affected by larger structures, maintaining a relationship with the seismic frequency and wavelength. The largest ΔKEF/ΔPEF values reached up to 3.42 × 108/3.24 × 108 J/m2 in model with the highest ε value, whereas up to 0.49 × 108/0.67 × 108 J/m2 in the model with the lowest ε value. In the fourth test case, similar types of structures (fractures) were analysed under different orientations in each model. The kinetic seismic energy fluxes/potential seismic energy fluxes were higher in the model formed by better‐oriented structures or parallel with respect to the propagation direction of the seismic‐acoustic wavefield. These energy differences between each test case show how not only the number of structures in a model and the ε values influenced the seismic‐acoustic wavefield and the kinetic seismic energy flux/potential seismic energy flux, but also the structural aspects, the intrinsic elastic properties (e.g. the density used in structures), location (separation between structures) and orientation of structures.