Detecting torrential processes from a distance with a seismic monitoring network

The detection of debris flows through seismic devices occurs at a certain distance from the channel bed. Ground vibration detectors are installed outside of the flow path, usually along the banks of the torrent or on the surrounding valley slopes, in order to avoid damage or even complete destruction. Seismic networks, however, are also prone to detect other earth surface processes that can be confused with the passage of a debris flow. Recognizing these other processes is important, particularly when the seismic network is used for warning purposes and not only for monitoring. To this aim, two seismic networks were installed in two instrumented basins located in the Italian Alps. Both networks were designed for debris flow monitoring purposes and for testing warning algorithms. In this paper, the seismic recordings of torrential processes that occurred at different distance from the monitoring networks, within and outside the monitored channels, are presented and discussed. It was found that knowledge of the waveform that these different processes produce is critical to the successful design and implementation of seismic networks for debris flow warning. Copyright Springer Science+Business Media Dordrecht 2015