Icequakes coupled with surface displacements for predicting glacier break-off
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Date
2011Type
- Journal Article
Abstract
A hanging glacier at the east face of Weisshorn, Switzerland, broke off in 2005. We were able to monitor and measure surface motion and icequake activity for 25 days up to 3 days prior to the break-off. The analysis of seismic waves generated by the glacier during the rupture maturation process revealed four types of precursory signals of the imminent catastrophic rupture: (1) an increase in seismic activity within the glacier; (2) a change in the size–frequency distribution of icequake energy; (3) a modification in the structure of the waiting-time distributions between two successive icequakes; and (4) a correlation between the seismic activity and the log-periodic oscillations of the surface velocities superimposed on the global acceleration of the glacier during the rupture maturation. Analysis of the seismic activity led us to identify two regimes: a stable phase with diffuse damage and an unstable and dangerous phase characterized by a hierarchical cascade of rupture instabilities where large icequakes are triggered. Show more
Publication status
publishedExternal links
Journal / series
Journal of GlaciologyVolume
Pages / Article No.
Publisher
International Glaciological SocietyOrganisational unit
03738 - Sornette, Didier (emeritus) / Sornette, Didier (emeritus)
08726 - Funk, Martin (Tit.-Prof.)
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