
Open access
Date
2019-09Type
- Journal Article
Citations
Cited 10 times in
Web of Science
Cited 9 times in
Scopus
ETH Bibliography
yes
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Abstract
Hydraulic processes within and beneath glacial bodies exert a far-reaching control on ice flow through their influence on basal sliding. Within the subglacial system, rapid changes in these processes may excite resonances whose interpretation requires an understanding of the underlying wave mechanics. Here, we explore these mechanics using observations from a kHz-sampled pressure sensor installed in a borehole directly above the hard granite bedrock of a temperate mountain glacier in Switzerland. We apply a previously established theory of wave propagation along thin, water-filled structures such as water-filled voids, basal water layers, or hydraulic fractures. Within such structures, short-wavelength waves experience restoring forces due to compressibility and are composed of sound waves. Long-wavelength resonances, in contrast, experience restoring forces due to elasticity and are composed of anomalously dispersed crack waves or Krauklis waves. Our borehole observations confirm the occurrence of both sound and crack waves within the basal water layer. Using both the resonance frequencies and attenuation of recorded crack waves we estimate thickness, aperture and length of the resonating basal water layer patch into which we drilled. We demonstrate that high-frequency observations of subglacial hydraulic processes provide new insights into this evolving dynamic system. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000356785Publication status
publishedExternal links
Journal / series
Annals of GlaciologyVolume
Pages / Article No.
Publisher
International Glaciological SocietySubject
glacier hydrology; glacier seismology; subglacial processesOrganisational unit
09599 - Farinotti, Daniel / Farinotti, Daniel
09558 - Walter, Fabian (ehemalig) / Walter, F. ((former))
Funding
157551 - Glacial Hazard Monitoring with Seismology (GlaHMSeis) (SNF)
Related publications and datasets
Is part of: https://doi.org/10.3929/ethz-b-000524634
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Show all metadata
Citations
Cited 10 times in
Web of Science
Cited 9 times in
Scopus
ETH Bibliography
yes
Altmetrics