CDP mapping to obtain the fine structure of the crust and upper mantle from seismic sounding data: an example for the southeastern China

Abstract

We present an efficient and general approach of common depth point (CDP) mapping to image the fine structure of the crust and upper mantle. We use velocity model and reflector geometries which are the results of conventional interpretation, as a reference model to construct our CDP mapping of crust and upper mantle. After three steps (the calculation of CDP points and reflecting traveltimes, the determination of CDP mapping trajectories and the implementation of CDP imaging), reflection images were created by CDP mapping technique in which each time element of a seismic trace, beginning with the direct arrival, is mapped to reflection point. Our test of the method presented in this paper shows that the algorithm can quickly, accurately image the subsurfaces of the given model. The result of CDP mapping in the southeastern China shows that the depth of Moho is about 34 km, there are numerous reflection interfaces within the upper crust; and the Moho is a transition zone with a thickness of 2–3 km. The CDP mapping approach presented here can easily be extended to three dimensions and complex anisotropic media. The method can also be used to develop seismic attribute images of the crust and upper mantle.