Item: Infrasonic Monitoring of Snow Avalanches in the Alps
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Title: Infrasonic Monitoring of Snow Avalanches in the Alps
Proceedings: Proceedings, 2012 International Snow Science Workshop, Anchorage, Alaska
Authors:
- Ulivieri G. [ Dipartimento di Scienze della Terra, Università di Firenze, Via la Pira 4 50121 Firenze, Italy ] [ Item srl, Italy (www.item - geophysics.it) ]
- E. Marchetti [ Dipartimento di Scienze della Terra, Università di Firenze, Via la Pira 4 50121 Firenze, Italy ] [ Item srl, Italy (www.item - geophysics.it) ]
- M. Ripepe [ Dipartimento di Scienze della Terra, Università di Firenze, Via la Pira 4 50121 Firenze, Italy ]
- I. Chiambretti [ AINEVA, Trento, Italy ]
- V. Segor [ Regione Autonoma Valle dʼAosta, Italy ]
Date: 2012
Abstract: Validation of risk assessment of snow avalanches requires to identify the occurrence of avalanches. For this purpose, after a pilot experiment in Gressonay during the 2009-2010, in December 2010 we installed a permanent 4-elements, 140 m aperture, infrasound array in the Ayas Valley (Italian Alps) where natural avalanches are expected and controlled events are performed. The array consists in high sensitivity (10-3 Pa, 0.5-50 Hz) infrasonic sensors and a 4 channels, 24bits, A/D converter sampling at 100 Hz. Timing is achieved with a GPS receiver. Data are transmitted to the Department of Earth Sciences of the University of Firenze, where are recorded and processed in real-time. A multi-channel semblance analysis is carried out on the real-time infrasonic data set as a function of slowness, backazimuth and frequency content in order to detect all the possible signals. The results gained during 3- years-long test indicate that small-to-medium size powder avalanches can be detected in the short-tomedium range (<5 km). Despite array analysis allows to discards many natural (microbarom, earthquakes) and artificial (airplane, explosions) sources of infrasound, a network of 3 arrays will be deployed on Summer 2012 for a precise and automatic source location, which should allows a better discrimination between “noisy†and avalanches sources of infrasound. Precise location together with real-time monitoring automatically will provide information on potential sectors where avalanches might have occurred during the last 24h, thus providing crucial and reliable information for improving risk assessments.
Language of Article: English
Presenters: unknown
Keywords: infrasound array network, snow avalanche monitoring, risk assessment
Page Number(s): 723-728
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Digital Abstract Not Available
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