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| Titel |
Alpine glacier instabilities Processes and early warning perspectives |
| VerfasserIn |
Jerome Faillettaz, Martin Funk |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076360
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| Zusammenfassung |
| Alpine glacier instabilities are gravity-driven rupture phenomena. Three different types of
instabilities can be identified according to the thermal properties of the ice/bed interface. If
cold (1), the maturation of the rupture is shown to be associated with a typical time evolution
of surface velocities and seismic activity generated by the glacier. A prediction of the final
break-off is possible by using these precursory signs. For the other types of instabilities,
water plays of key role in the initiation and the development of the instability. If the
ice/bed interface is partly temperate (2), the presence of melt water at the interface
reduces its basal resistance which promotes the instability. No clear and easily
detectable precursory signs could be evidenced in this case, and the only way to
infer a possible instability initiation is to monitor the time and spatial evolution of
the thermal regime at the interface. The last type of instability (3) concerns steep
temperate glacier tongues switching for a couple of days/weeks during the melting
season into so called ”active phases” followed in rare cases into a major break off
event. Although such an event prediction remains far from being realizable yet,
we could identify critical conditions promoting the final instability with a newly
developed numerical modeling including water flow in a subglacial drainage network. |
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