Seismic Constraints on Damage Growth Within an Unstable Hanging Glacier


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Date

2023-05-16

Publication Type

Journal Article

ETH Bibliography

yes

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Data

Abstract

Forecasting hanging glacier instabilities remain challenging as sensing technology focusing on the ice surface fails to detect englacial damage leading to large-scale failure. Here, we combine icequake cluster analysis with coda wave interferometry constraining damage growth on Switzerland's Eiger hanging glacier before a 15,000 m3 break-off event. The method focuses on icequake migration within clusters rather than previously proposed “event counting.” Results show that one cluster originated from the glacier front and migrated by 13.9(±1.2) m within 5 weeks before the break-off event. The corresponding crevasse extension separates unstable and stable ice masses. We use the measured source displacement for damage parametrization and find a 90% agreement between an analytical model based on damage mechanics and frontal flow velocities measured with an interferometric radar. Our analysis provides observational constraints for damage growth, which to date is primarily a theoretical concept for modeling englacial fractures.

Publication status

published

Editor

Book title

Volume

50 (9)

Pages / Article No.

Publisher

American Geophysical Union

Event

Edition / version

Methods

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Geographic location

Date collected

Date created

Subject

environmental seismology; hanging glaciers; coda wave interferometry; icequake multiplets; natural hazards

Organisational unit

09599 - Farinotti, Daniel / Farinotti, Daniel check_circle

Notes

Funding

157551 - Glacial Hazard Monitoring with Seismology (GlaHMSeis) (SNF)

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