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Erosion and sediment transfer processes at the front of rapidly moving rock glaciers: Systematic observations with automatic cameras in the western Swiss Alps

  • Kummert, Mario Department of Geosciences/Geography, University of Fribourg, Switzerland
  • Delaloye, Reynald Department of Geosciences/Geography, University of Fribourg, Switzerland
  • Braillard, Luc Department of Geosciences/Geography, University of Fribourg, Switzerland
    08.10.2017
Published in:
  • Permafrost and Periglacial Processes. - 2017, vol. 29, no. 1, p. 21–33
English When connected to torrential channels, the fronts of active rock glaciers constitute important sediment sources for gravitational transfer processes. In this study, a 2013– 16 time series of in situ webcam images from the western Swiss Alps was analyzed to characterize the erosion processes responsible for sediment transfer at the front of three rapidly moving rock glaciers and their temporal behavior. The main erosion processes comprised rock fall, debris slide, superficial flow and concentrated flow. These processes were induced by (i) changes of the frontal slope angle produced by rock glacier advance, and (ii) increases in water content of the sediments at the rock glacier front due to melt processes and rainfall. Erosion almost ceased during winter, when the front was frozen and snow‐covered. The onset of snowmelt triggered an active period of high‐frequency erosion events. After the melt period, sediment transfer continued as occasional rock falls, while other erosion processes occurred only during or following rainfall events. Intense regressive erosion phases that triggered debris flows were rare and occurred when enhanced snowmelt and/or recurring rainfall induced substantial groundwater flow on the debris slopes directly below the rock glacier fronts.
Faculty
Faculté des sciences et de médecine
Department
Département de Géosciences
Language
  • English
Classification
Geology
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/306536
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