I am trying to model the effect that stratigraphy and the presence of discontinuities have in the dispersion curves of a MASW survey. First i apply the load (Ricker wavelet) on the free surface to record the direct, refracted and reflected waves. Then i process the OpenSees output in the Geopsy software to visualize the seismogram. The problem arises when i try to analyze the wave fronts, since superposition is generated due to the bounce at the boundaries and by the wave fronts originated by the free vibration in wich the surface remains.
The question is... how can i quickly attenuate the free vibration in the surface after the load is applied??? and how can i implement quiet boundaries to avoid wave reflections??
At the moment i'm using dashpots on the boundaries to avoid reflections (but it doesn't work very well) and applying rayleigh damping (in layers) to try to quickly dampen the load on the free surface but not so fast in depth.