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 at tempt to characterise them for monitoring purposes. The avalanches were art ificially released and the corresponding seismic signals were recorded at d ifferent sites within a radius of up to 3 km together with the video images with a common time reference. The results obtained indicate that avalanche s following the same path and recorded at the same site present similar sei smic signals. A relationship between the avalanche seismic signals (amplitu de, 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. The se results lend support to the use of seismic signals as an efficient metho d of monitoring areas where avalanches are frequent and human observation i s difficult. (C) 2000 Elsevier Science Ltd. All rights reserved.