Perform long-term monitoring of the North Alfeo Fault (offshore Catania, Sicily) using a fiber optic cable, a network of seafloor geodetic stations and a network of ocean bottom seimometers (OBS) in the framework of the ERC Advanced Grant project FOCUS.

The main objective of the series of high-seas marine expeditions related to the ERC Advanced Grant FOCUS, (Oct. 2018 - Sep. 2025) is to test the technique of laser reflectometry to detect small (1 - 2 cm) tectonic displacements caused by active submarine faults and thereby improve our understanding of the natural hazards in the study area (Fig. 1). For this project to be successful, other complementary observational techniques must also be applied (seafloor geodesy, seismology (Fig. 2), microbathymetric mapping of the seafloor, sediment coring, etc.). Preliminary results documenting natural cable disturbances (Gutscher et al., 2023, EPSL) seem to support an origin from sea-bottom currents and underscore the need for better oceanographic observations (structure of water masses, bottom currents, currents caused by internal waves, etc.).

Fig. 1: Regional location map (Gutscher et al. 2023, EPSL) showing the existing electro-optical cable (thick black line) and the 6-km-long Focus cable (purple line) crossing the North Alfeo Fault in 4 locations. Black triangles with yellow rims show the positions of the seafloor geodetic stations deployed during FocusX2.

Fig. 2: Regional location map of seismic stations, showing the permanent land stations (magenta triangles) the temporary network of land stations (blue triangles) and the temporary network of ocean-bottom seismometers (diamonds). The colored diamonds show the positions of the 20 OBS deployed for 1 year.