Surface-Waves Extraction Using a Shot-Receiver-Time Transformation

Summary Seismic data contain rich information carried by different types of waves, such as direct arrivals (P- and S-waves), reflections, diffractions and surface-waves. In order to utilize a specific type of wave, one needs to isolate this wanted signal from others. We propose a method to extract and/or remove mainly the dispersive surface-waves based on their geometrical property in the shot-receiver-time domain for seismic data acquired along 2D acquisition profiles. We first assemble all shot gathers into a pseudo 3D data with dimensions of shot locations, receiver locations, and time. The shot-receiver-time domain enables us to process the data along different dimensions, not restricted to the shot domain only. With the assumption of a 1D velocity model, we find that the dispersive surface-waves in a shot gather behave linearly in a time isochrone, which cuts through all shots and receivers. The linear geometrical property of the surface-waves in the time isochrone allows us to extract them efficiently and effectively using for example curvelet-based transforms. By applying the method along the time isochrones for the time samples where surface-waves are present, surface-waves can be extracted from the pseudo 3D data. We exemplify this method using a synthetic data and a field data.