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Borehole deformation measurements and internal structure of some rock glaciers in Switzerland
Author(s) -
Arenson Lukas,
Hoelzle Martin,
Springman Sarah
Publication year - 2002
Publication title -
permafrost and periglacial processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 76
eISSN - 1099-1530
pISSN - 1045-6740
DOI - 10.1002/ppp.414
Subject(s) - permafrost , geology , rock glacier , borehole , glacier , deformation (meteorology) , geomorphology , bedrock , shear (geology) , creep , glaciology , glacier morphology , geotechnical engineering , mineralogy , petrology , ice stream , hydrogeology , cryosphere , climatology , oceanography , materials science , metamorphic petrology , composite material , sea ice
In order to understand the mechanical processes that influence the deformation patterns of active rock glaciers, information about local horizontal and vertical deformations as well as knowledge of the internal structure and the temperature distribution is necessary. Results from borehole deformation measurements of three sites in the Swiss Alps show that despite different internal structures, similar phenomena can be observed. In contrast to temperate glaciers, permafrost within rock glaciers has distinct shear zones where horizontal and vertical differential movements are concentrated. In addition, a reduction in volume can be caused by compressive flow due to the presence of air voids within the permafrost. The flow velocity depends on the temperature, the surface and bedrock slopes of the rock glacier, and the composition of the ice‐rich frozen ground. Within degrading permafrost, the ice content decreases, the creep velocity increases and the shear zone rises towards the surface, where seasonal temperature changes and the presence of liquid water might also influence deformation. Copyright © 2002 John Wiley & Sons, Ltd.