Salvus excels in the large-scale computation of fully 3-D wavefields in realistic and complicated environments. In this use case, Salvus was used to investigate the character of vibrational strain signals recorded along an ocean bottom fiber-optic cable. High resolution surface and seabed topography, along with the accurate coupling of both viscoelastic and acoustic wavefields, are automatically included using our simple Python-based interface. Simulations such as these help researchers investigate new and exciting applications of distributed acoustic sensing (DAS). The following illustration highlights a few of the complexities Salvus handles - click on it to see a video of these waves propagating. All this readily scales from running on laptops, to GPU clusters all the way to big machines with thousands of cores. The simulation rendered below took less than a few minutes to run on a single GPU.