A STUDY OF INFRASONIC SIGNALS OF DEBRIS FLOWS — IJEGE
 
 
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A STUDY OF INFRASONIC SIGNALS OF DEBRIS FLOWS



Abstract:
Mass movements such as debris flows, rock fall and snow avalanches are sources of sub-audible sounds in the low frequency infrasonic and seismic spectrum. Recent studies indicated that debris flow-generated signals are of significant amplitude and occupy a relatively noise free band in the low frequency acoustic spectrum. Infrasound signals have the ability to propagate kilometres from the source, thereby allow monitoring of mass movements from a remote location. This study presents debris flow monitoring at four international sites - Lattenbach, Tyrol (Austria), Illgraben, Valais (Switzerland), and the MiDui and GuXiang Glacier, Tibet (China). The infrasound sensors used were the Chinese sensor (DFW I-III) or the German sensor (Gefell WME 960 H). The results show that debris flows emit detectable low frequency infrasonic signals (1-20 Hz) that are correlated to seismic signals. The infrasound sensors detect the phenomena before it reaches the sensors, depending on the landscape, distances and the sensitivity of the equipment.

Authors:
Arnold Kogelnig - Institute of Mountain Risk Engineering, University of Natural Resources and Life Sciences, Vienna, Austria
Johannes Hübl - Institute of Mountain Risk Engineering, University of Natural Resources and Life Sciences, Vienna, Austria
Emma Suriñach - Grup d’Allaus (RISKNAT), Dept. Geodinàmica i Geofisica, Fac. de Geologia, Universitat de Barcelona, Spain
Ignasi Vilajosana - Grup d’Allaus (RISKNAT), Dept. Geodinàmica i Geofisica, Fac. de Geologia, Universitat de Barcelona, Spain
Shucheng Zhang - Institute of Mountain Hazards and Environmnent, Chinese Academy of Sciences and Ministery of Water Ressources, Chengdu, China
Nanyan Yun - Mechanics College, Southwest Jiao Tong University, Chengdu, China
Brian W. McArdell - Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
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