The Bedretto Underground Laboratory for Geosciences and Geoenergies (BULGG) Seismic Network, Switzerland

Abstract

The Bedretto Underground Laboratory for Geoenergies and Geosciences (BULGG) is a unique research infrastructure located in the middle of a 5.2 kilometers long tunnel that connects Ticino with the Furka railway tunnel, in south-central Switzerland. BULGG is equipped with state of the art instruments that allow to conduct experimental research in various fields. From a seismological point of view, we aim to monitor seismicity that occurs during experiments, as well as monitoring local earthquakes, and possibly induced or run-away seismic events. To accomplish that we set up two real-time monitoring systems based on the SeisComP software, i.e. (i) background seismicity monitoring, and (ii) experimental monitoring. The background monitoring, which is the backbone network, consists of surface and tunnel broadband stations, short period sensors, accelerometers, and geophones sampled at various frequencies (200-2000Hz). Acoustic emission sensors, and an accelerometer sampled at 200kHZ constitute the experimental instance. All sensors stream to a common seedlink server which provides data to multiple clients for processing, real-time visualization, archiving, and risk control via dedicated software. A standard workflow is applied to both background and experimental monitoring that includes, automatic picking, automatic phase association and location, and magnitude estimation. Advanced methods are also applied in real-time, such as, real time double-difference relocation, and real-time earthquake detection based on waveform cross-correlation (template matching). Overall, BULGG is a unique environment to test several types of instruments and implement novel methods on observational and network seismology across scales. Bedretto Team: (see http://www.bedrettolab.ethz.ch/en/home/ for more details)