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Seismic activity and surface motion of a steep temperate glacier: a study on Triftgletscher, Switzerland

  • Dalban Canassy, Pierre Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, Switzerland
  • Faillettaz, Jérome Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, Switzerland
  • Walter, Fabian Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, Switzerland - Swiss Seismological Service (SED), ETH Zürich, Switzerland
  • Huss, Matthias Department of Geosciences, University of Fribourg, Switzerland
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    01.06.2012
Published in:
  • Journal of Glaciology. - 2012, vol. 58, no. 209, p. 513-528
English The tongue of Triftgletscher, Switzerland, is particularly susceptible to major break-off events due to its steep slope. In order to detect precursors of such an event, we monitored the local seismic activity and detected 2426 icequakes with sources located in an area ranging between 2050 and 2350 m a.s.l. Events triggered by cracks and icefalls were recorded, but no precise distinction between the two sources was possible using duration or frequency criteria. Clusters of seismic activity were located and confirmed by visual observations. We performed a surface motion analysis and found that surface motion was driven significantly by runoff changes at a timescale of 2-3 days. By means of a statistical analysis, a power-law behaviour of the released seismic energy distribution was discerned at certain times during the period investigated. Variations in power-law exponent values indicated that low- and high-energy events predominantly occurred during phases of enhanced and reduced surface motion, respectively. Substantial releases of seismic energy likely to signal the glacier recoupling were detected during phases of decreasing runoff. Clues to potential seismic precursors of break-off events are discussed.
Faculty
Faculté des sciences et de médecine
Department
Département de Géosciences
Language
  • English
Classification
Hydrology
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/302699
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