Detecting snow avalanches with seismic stations in North-east Italy: first results of data set analysis

Abstract

The Regional Agency for the Environmental Prevention and Protection of Veneto (Agenzia Regionale per la Prevenzione e Protezione Ambientale del Veneto, ARPAV) was established in October 2007 to monitor and prevent environmental risks in the Veneto region, in North-eastern Italy. The Italian National Institute for Oceanography and Experimental Geophysics (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, OGS), after the strong earthquake (magnitude M=6.4) occurred in 1976 in the Friuli-Venezia Giulia region, started to operate the North-east Italy (NI) seismic network: it currently consist of 11 very sensitive broad band and 21 more simple short period seismic stations, all telemetered to and acquired in real time in the Seismological Research Center (Centro di Ricerche Sismologiche, CRS) of the OGS in Udine. In June 2007 OGS installed in cooperation with the Italian National Institute for Geophysics and Volcanology (Istituto Nazionale di Geofisica e Vulcanologia, INGV) a broad band seismic station in Agordo, a site located in the Dolomites mountains in the Veneto region. During the last 2008/09 winter season, in the whole Dolomites, above the altitude of 1,200m, between 250 and 350 cm of fresh snow have fallen: similar snowfall events occurred in the last 80 years only in 1951, 1959, 1960 and 1979. The large amount of snow fell failed to consolidate and in the Dolomites, the study area of this work, the spontaneous avalanche phenomena was very intense, with several large avalanches reaching the bottoms of the valleys, and that were also detected by the OGS seismic network: avalanches of such characteristics were not observed since February 1977 and January 1987. In this work we correlate seismic parameters (such recording length) with physical characteristics of the avalanches triggering them (such run-out).