Integrating the FXLand network into the real‑time earthquake surveillance and monitoring system of Italy

Abstract

The Ionian margin of southern Italy is one of the most complex geodynamic regions in the central Mediterranean, where ongoing convergence between the African and Eurasian plates results in intense seismic activity and highly heterogeneous crustal structures. To improve seismic monitoring in this region, within the framework of the ERC Advanced Grant FOCUS (2018‑2025), a temporary onshore seismic network (FXLand) was deployed along the Ionian coasts of Sicily and Calabria from December 2021 to June 2023, complementing a marine array of ocean‑bottom seismometers operating during the same period. In this study we describe the deployment and performance of the 13 temporary broadband stations of FXLand. The network was integrated in real time into the Italian national seismic surveillance system, enhancing data availability and coastal network geometry. During the deployment, FXLand recorded, more than 1,500 local earthquakes and more than 200 teleseismic events with magnitude M ≥ 6. We also present results from the analysis of three seismic sequences that occurred during the network operational period. The application of a Template Matching technique to the combined permanent station and FXLand network dataset, we significantly increased the number of detected low‑magnitude earthquakes in onshore area, improving catalog completeness compared to real‑time surveillance and Italian Seismic Bulletin. On the other hand, the offshore sequence highlights the main limitations of land‑based networks in detecting and accurately locating submarine seismicity. The integration of marine observations from the ocean‑bottom seismometer network in the Ionian Sea is expected to provide substantial improvements in the detection and location accuracy of offshore earthquakes, contributing to a more complete characterization of seismic activity along the Ionian margin.