Integrating UHR Diffraction Imaging and Spectral Decomposition for Enhanced Offshore Windfarm Geohazard Mapping

Summary This study proposes a novel approach that combines diffraction imaging with matching-pursuit spectral decomposition to enhance geohazard mapping using 3D Ultra-High-Resolution Seismic (UHRS) data from the Dutch TNWWFZ. This methodology reveals sub-wavelength geological heterogeneities typically missed by conventional seismic methods, posing potential geohazards for offshore construction. A customized diffraction imaging workflow was employed to highlight discontinuities associated with boulder-rich sediments and possible gas accumulations. Wavefield separation and Kirchhoff-based imaging were utilized to produce detailed diffraction volumes, which were subsequently enhanced through matching-pursuit spectral decomposition. This targeted decomposition highlighted frequency bands specifically sensitive to gas indications and boulder fields. The resulting frequency-dependent diffraction attribute volumes were merged into a single comprehensive cube, enhancing the visibility of subtle geological features, surpassing the resolution obtainable from migrated reflection images. This approach offers a robust tool for identifying hazard zones, thereby supporting safer and more reliable offshore foundation designs.