Railway Distributed Acoustic Sensing data as an aid to earthquake monitoring in northernmost Sweden

The Swedish Transport Administration (STA) currently monitors the railway between Kiruna and the Swedish-Norwegian border with Distributed Acoustic Sensing (DAS), a distance of approximately 130 km. In collaboration with STA and Luleå University of Technology, the Swedish National Seismic Network (SNSN) has established data transmission on a request basis from the interrogator. As the railway crosses the Pärvie fault, the largest known, and still very active, glacially triggered fault, we hope to significantly improve detection and analysis of small earthquakes on that section of the fault. In this presentation we will show how we define low noise sections of the cable, using local and teleseismic events, and then use these as individual seismic stations. Over the 130 km, as the railway winds its way across the mountains, the cable generally runs in directions from N-S via NW-SE to W-E, providing many possible incidence directions. We discuss the technicalities of the data sharing, the existing metadata problems, how the DAS data is analyzed and incorporated into the routine processing at SNSN.