Regional velocity modelling of the North German Basin in Saxony-Anhalt as part of the TUNB Velo 2.0 project

Reliable velocity models are crucial for accurate seismic time-to-depth conversion. Existing regional velocity models in Saxony-Anhalt date back to the 1970’s, indicating the demand for updated models based on recent data. Current best practices in geophysical modelling call for the development of three-dimensional velocity models to account for the structural complexity of the subsurface.

A modelling workflow has been developed for the northern part of Saxony-Anhalt, building upon the 3D structural model of the North German Basin from the TUNB project. Vertical seismic profiles from more than 200 boreholes form the essential data basis. Initial velocities and depth gradients for 8 velocity intervals from top Cenozoic to base Zechstein were determined. Linear interval velocity-depth functions were derived and calculated within a 3D voxel-based model. Finally, the model is aligned with recently developed ones of the neighboring federal states and compared to vintage velocity models.

Our workflow represents an efficient and modern approach for 3D velocity modelling and can be easily extended to other areas and 3D models. The large-scale velocity model will serve as starting model for future (re-)processing campaigns and supports planning and interpretation of upcoming local seismic studies.