Study of seismic signals of artificially released snow avalanches for monitoring purposes

Seismic signals generated by artificially released avalanches were studied from the seismological viewpoint in the time and frequency domains in an attempt to characterise them for monitoring purposes. The avalanches were artificially released and the corresponding seismic signals were recorded at different sites within a radius of up to 3 km together with the video images with a common time reference. The results obtained indicate that avalanches following the same path and recorded at the same site present similar seismic signals. A relationship between the avalanche seismic signals (amplitude, frequency content and wave trains) and the avalanche path was observed. The sources of the recorded seismic signals corresponds to avalanche path slope changes, interaction with obstacles and phenomena associated with the stopping stage of the avalanche. Local site effects were also present. These results lend support to the use of seismic signals as an efficient method of monitoring areas where avalanches are frequent and human observation is difficult. (C) 2000 Elsevier Science Ltd. All rights reserved.