Study of debris-flow initiation through the analysis of seismic signals

Abstract

Monitoring data gathered in the headwaters of the Gadria catchment, eastern Italian Alps, have been analysed to study debris-flow initiation. The active channel, located at 2200 m a.s.l., was instrumented with a geophone, a time-lapse video camera and a rain gauge. The peak amplitude and duration of the seismic signals and their frequency content were analysed and compared with video images. Results showed that different seismic sources produced signals with different characteristics and that it is possible to discriminate the most intense runoff by analysing the combination of peak amplitude and duration of the seismic signal. The further development of this research would be to create an algorithm able to automatically classify the seismic sources and identify intense channel processes that can generate debris flows. In perspective, the combination of seismic detection in the initiation area with monitoring just above the infrastructures at risk could represent an effective solution to expand the lead time of an early warning system.