Reliable Estimation of Avalanche Activity Using Seismic Methods

In order to improve natural avalanches forecast, MeteoFrance has developed an operational system for automatic, quasi real-time estimation of the avalanche activity. It is based on the detection of the seismic signal associated with avalanches. Avalanches represent only about 10% of the recorded seismic signals, all the others being unwelcome signals that must be eliminated. This task requires a complete analysis of the signal. We have developed a system (named SARA) which uses time-frequency analysis and fuzzy logic to recognize avalanche signals. The average success rate of our system is about 90%. The results provided by the SARA system are compared with other parameters related to avalanche activity. SARA proves able to follow the evolution of avalanche activity in almost real time. Concrete applications, such as surveillance of avalanche prone zones, are considered.