Seismic interferometry as a tool for improved imaging of the heterogeneities in the body of a landfill

It is challenging to image and characterize the body of a landfill. High-density areas that act as obstructions to fluid flow are of specific interest to the landfill operators (e.g., for improvement of treatment technologies), and thus their imaging is important. In seismic reflection sections, such areas manifest themselves as sources of scattered energy. The heterogeneities inside the landfill, in addition to the surface-wave energy which is difficult to remove, add to the complexity in the seismic data. We propose to make use of seismic interferometry (SI) not only as a tool to improve the imaging of the scatterers, but also as a tool to remove the undesired surface-wave energy. We investigate the results obtained from application of SI to field seismic reflection data recorded at a landfill. We show that the data, retrieved by SI, image the scattered energy better than the seismic reflection data when the latter is processed in a conventional way. The increased stacking power of SI and its implicit consideration of multiple scattering result in a better illumination of the scatterers. We also use SI to predict the surface-wave energy and remove it from the original seismic reflection data using an adaptive subtraction method. The result from the adaptive subtraction when compared to the reflection data, processed in a conventional way, shows improved imaging, especially of layers in the landfill. Combined interpretation of the stacked reflection sections together with the velocity fields obtained from the three different datasets (conventional seismic reflection, SI and adaptive subtraction) leads to an improved interpretation.