Weighted Multipath Summation as a Tool for Imaging Localized Near-surface Inhomogeneities

We present a new approach to imaging shallow subsurface objects in 3D space based on weighted multipath summation of seismic waves diffracted by the target objects. The method is a further development of the recently proposed multipath summation technique, where the imaging is performed by stacking the diffracted waves along all possible diffraction time surfaces having a common apex at the given point. The multipath approach does not require any explicit information on velocities since the summation is performed for all possible velocity values within a wide specified range. We show that the images obtained by the multipath summation can be considerably improved by applying a proper weighting function. Moreover, the weighted multipath summation can also produce a reliable estimate of velocity above the diffractor. The obtained velocity can be used to further improve the image quality. Application of the proposed method is demonstrated by synthetic and real data examples.