Evidence of frost-cracking inferred from acoustic emissions in a high-alpine rock-wall

Ice formation within rock is known to be an important driver of near-surface frost weathering as well as of rock damage at the depth of several meters, which may play a crucial role for the slow preconditioning of rock fall in steep permafrost areas. This letter reports results from an experiment wh...

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Bibliographic Details
Published in:Earth and planetary science letters 2012-08, Vol.341-344, p.86-93
Main Authors: Amitrano, D., Gruber, S., Girard, L.
Format: Article
Language:English
Subjects:
Acoustic emission
Damage
Earth Sciences
Environmental Sciences
Freezing
frost-cracking
Geophysics
Global Changes
Mathematical models
mechanical weathering
Melting
Physics
Receiving
Rock
scaling properties
Sciences of the Universe
Stresses
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Summary:Ice formation within rock is known to be an important driver of near-surface frost weathering as well as of rock damage at the depth of several meters, which may play a crucial role for the slow preconditioning of rock fall in steep permafrost areas. This letter reports results from an experiment where acoustic emission monitoring was used to investigate rock damage in a high-alpine rock-wall induced by natural thermal cycling and freezing/thawing. The analysis of the large catalog of events obtained shows (i) robust power-law distributions in the time and energy domains, a footprint of rock micro-fracturing activity induced by stresses arising from thermal variations and associated freezing/thawing of rock; (ii) an increase in AE activity under sub-zero rock-temperatures, suggesting the importance of freezing-induced stresses. AE activity further increases in locations of the rock-wall that are prone to receiving melt water. These results suggest that the framework of further modeling studies (theoretical and numerical) should include damage, elastic interaction and poro-mechanics in order to describe freezing-related stresses. ► Monitoring of acoustic emission in the field during freezing–thawing cycles. ► Power-law distribution of damage events in energy and time domains. ► Damage activity related to negative temperature and liquid water availability. ► Spatial heterogeneity of the acoustic emission with important consequence for frost weathering estimation at large scales.
ISSN:0012-821X
1385-013X
DOI:10.1016/j.epsl.2012.06.014