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We analysed passive records of distributed acoustic sensing on an existing submarine fiber-optic cable in the Dutch North Sea. We find that strong Scholte waves are present in the 0.5–3 Hz frequency range and that their velocity dispersion characteristics can be used to infer shallow shear-wave velocity profiles along the cable, providing in particular a cost-efficient technology for shallow geotechnical characterization. The retrieval of virtual shots containing the Scholte waves and the computation of dispersion images are key in this process. We study how the quality of the virtual shots and of the dispersion images depend on data selection parameters. We find in particular that the quality of the virtual shots vary noticeably when considering different time periods, even just few hours apart. This suggests that adopting a selective approach during the cross-correlation and stacking process allows to obtain more accurate virtual shots and so better dispersion images for subsequent inversion to shear-wave velocity profiles.