Wave images of the crustal structure from refraction and wide-angle reflection migrations along the DOBRE profile (Dnieper–Donets paleorift)

The DOBRE profile crosses the Donbas Foldbelt that is an uplifted part of the Dnieper–Donets paleorift. The depth to the basement reaches 20 km. The refraction and wide-angle reflection survey was carried out along this 360 km profile with 245 recording stations and 11 shot points (DOBREfraction'99 Working Group et al., 2003). The velocity modeling traced three continual boundaries: the basement surface, the intra-crustal boundary and the Moho. The refraction and wide-angle reflection migrations, applied to the data, enable to reveal some new structural features of the boundaries. It determines a system of faults which divide the basement into several flat segments with stepwise increasing of their depths. In the central part of the profile the intra-crustal boundary is imaged which corresponds to a strong refraction boundary at a depth of 15–25 km. The Moho was traced as a weak boundary at a depth of 35–40 km beneath the Donbas and the crust–mantle transition zone is characterized by thick heterogeneous zone of lens form. ► The refraction and wide-angle reflection migration method is developed. ► The method was applied to the seismic data obtained in the Donbas paleorift area. ► As a result a system of faults and a rift graben were revealed in the basement. ► The crust-mantle transition zone is a thick heterogeneous zone of lens form.