Simulations of seismic waveforms observed on the IRIS subsea cable, connecting Iceland and Ireland

This study investigates the use of subsea communication cables as seismic monitoring instruments. We simulate the waveforms observed on 17 spans of the Iceland-Ireland subsea telecommunications cable, following the framework presented in Fichtner et al., 2022.  We use an open source spectral-element wave propagation code (SPECFEM3D GLOBE) to simulate strain rate at a dense set of points along the cable. The simulations incorporate realistic physical conditions, including the effects of topography, gravity, crustal structure, ocean load and cable geometry, and are executed on the Elja HPC platform, using 150 CPUs.

A Python-based pipeline processes and visualizes simulated strain data, supporting comparisons with real-world observations. This pipeline lays a foundation for a software library for analysis of seismic subsea cable data.Preliminary results indicate alignment between simulations and observations, with ongoing refinements addressing discrepancies caused by environmental noise and measurement uncertainties. The ability to model the observed strain response on the fiber optic cable, enables the incorporation of this dataset into traditional seismological applications, expanding observational coverage and contributing to the understanding of seismic processes in areas not accessible to traditional seismic networks.