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| | Abstract | | From the viewpoint of spatial sampling in reflection seismic exploration, we show effects of scattered waves on subsurface imaging by using numerical simulation of seismic wave field. We consider two types of noise in seismic waveform: one consists of the random noise in time series, and the other consists of incoherent scattered waves generated by random isotropic heterogeneity. The latter is a noise-like wave field caused by multiple scattering of seismic waves. The final CMP section contains disturbance due to the noise-like waves. We employed finite difference method for modeling 2-D acoustic wave field in random heterogeneous media. Our numerical experiments indicate that denser the spatial sampling of seismic wave, lesser the random noise in seismic reflection image for the case of random time-series noise. On the other hand, the denser spatial sampling does not improve resolution of the CMP section when subsurface structure contains random heterogeneity until the interval of spatial sampling becomes shorter than the characteristic length of random isotropic heterogeneities. We also indicate that the spatial sampling should be smaller than the characteristic size of heterogeneities to avoid spatial aliasing. |
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