Regional-scale seismic monitoring using distributed acoustic sensing on telecommunication fibers: the Friuli Venezia Giulia experience

Distributed Acoustic Sensing (DAS) is rapidly emerging as a powerful complement to conventional seismic networks, enabling dense and continuous ground-motion monitoring by exploiting existing fiber-optic telecommunication infrastructures. In this contribution we present the design, implementation, and first results of a regional-scale DAS seismic monitoring network deployed in Friuli Venezia Giulia (NE Italy), developed through a close collaboration between the regional authorities, the public ICT provider INSIEL, and the scientific community.The DAS infrastructure is an integral part of the SMINO network, the multi-sensor seismic and geodetic monitoring system for north-eastern Italy operated by OGS, and is fully integrated within its operational framework. The network is based on five strategically distributed interrogation points across the region, collectively instrumenting nearly 250 km of telecommunication fibers belonging to the regional backbone. This configuration provides several tens of thousands of virtual sensing channels with meter-scale spatial sampling, covering urban areas, transportation corridors, and heterogeneous geological settings. To our knowledge, this represents one of the most extensive—and likely the largest—operational regional DAS seismic monitoring networks currently deployed in Europe.We describe the criteria adopted for fiber selection, network geometry, and acquisition parameters, with particular emphasis on signal optimization, performance, and long-term operational robustness. Examples of recordings from local and regional earthquakes demonstrate the capability of the system to capture coherent seismic wavefields, clear phase arrivals, and spatial variability of ground motion. The network also systematically records anthropogenic signals, which are discussed both as a challenge for data quality control and as an opportunity for multi-purpose environmental monitoring.Finally, we address the integration of DAS data into existing seismic and civil protection workflows, including real-time data streaming, event detection, and rapid situational awareness. The Friuli Venezia Giulia experience demonstrates the maturity and added value of fiber-optic sensing for operational seismology at regional scale.