Characterization of icequake mechanisms on the Argentière glacier by 3-D elastic full waveform inversion
Abstract
Glaciers are key components of the global climate system and sensitive indicators of environmental change. Their dynamics generate diverse seismic signals, whose source mechanisms offer valuable insights into their internal stress conditions. While moment t ensor inv ersion has been applied to icequakes on a few alpine and polar glaciers, it had not yet been implemented on the Argentière Glacier (French Alps). In this study, we conduct a systematic characterization of icequake source mechanisms based on a dense data set of 14 057 near-surface events recorded by 98 three-component sensors deployed at the surface of the glacier during the RESOL VE project. W e apply a full waveform inversion method to jointly reconstruct the moment tensor and the source time wavelet for each event. The moment tensor Green's functions used in the inversion are computed through numerical modelling of elastic wave pr opag ation in a 3-D medium, incorporating real surface topography. This approach allows us to exploit the full complexity of the recorded seismic signals and to move beyond previous analysis based on simplified models and single-component data. The results reveal a clear dominance of opening-type (tensile crack) mechanisms, consistent with e xtensional str ess r egimes at the cr evasse locations, with principal str ess dir ection almost perpendicular to the local cr evasse orientations. The e x ceptional size of the catalogue enables a detailed investigation of spatial patterns in source mechanisms, particularly highlighting structural complexity in the heavily crevassed downstream zone. The distribution of extensional and compressional mechanisms further indicates a highly heter ogeneous str ess field at the glacier surface, influenced by local crevasse geometry. Depth-dependent variations in the reconstructed moment tensors suggest that deeper events tend to involve more isotropic components, likely r eflecting pr essur e-driven failur e under overbur den str ess. These findings demonstrate the pot ential of full wav eform inversion to characterize the source mechanisms associated with the icequakes on a glacier. This work r epr esents a significant step towards integrating seismological modelling with glaciological interpretation in alpine environments.
Related
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BibTeX
@article{brossier2026characterization,
title = {{Characterization of icequake mechanisms on the Argentière glacier by 3-D elastic full waveform inversion}},
author = {R Brossier and F Gimbert and L Métivier and P Roux and J Thurin},
journal = {Geophysical Journal International},
year = {2026},
month = sep,
doi = {10.1093/gji/ggag103},
url = {https://hal.science/hal-05761342v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Characterization of icequake mechanisms on the Argentière glacier by 3-D elastic full waveform inversion
AU - R Brossier
AU - F Gimbert
AU - L Métivier
AU - P Roux
AU - J Thurin
PY - 2026
DA - 2026/09/23
JO - Geophysical Journal International
DO - 10.1093/gji/ggag103
UR - https://hal.science/hal-05761342v1
AB - Glaciers are key components of the global climate system and sensitive indicators of environmental change. Their dynamics generate diverse seismic signals, whose source mechanisms offer valuable insights into their internal stress conditions. While moment t ensor inv ersion has been applied to icequakes on a few alpine and polar glaciers, it had not yet been implemented on the Argentière Glacier (French Alps). In this study, we conduct a systematic characterization of icequake source mechanisms based on a dense data set of 14 057 near-surface events recorded by 98 three-component sensors deployed at the surface of the glacier during the RESOL VE project. W e apply a full waveform inversion method to jointly reconstruct the moment tensor and the source time wavelet for each event. The moment tensor Green's functions used in the inversion are computed through numerical modelling of elastic wave pr opag ation in a 3-D medium, incorporating real surface topography. This approach allows us to exploit the full complexity of the recorded seismic signals and to move beyond previous analysis based on simplified models and single-component data. The results reveal a clear dominance of opening-type (tensile crack) mechanisms, consistent with e xtensional str ess r egimes at the cr evasse locations, with principal str ess dir ection almost perpendicular to the local cr evasse orientations. The e x ceptional size of the catalogue enables a detailed investigation of spatial patterns in source mechanisms, particularly highlighting structural complexity in the heavily crevassed downstream zone. The distribution of extensional and compressional mechanisms further indicates a highly heter ogeneous str ess field at the glacier surface, influenced by local crevasse geometry. Depth-dependent variations in the reconstructed moment tensors suggest that deeper events tend to involve more isotropic components, likely r eflecting pr essur e-driven failur e under overbur den str ess. These findings demonstrate the pot ential of full wav eform inversion to characterize the source mechanisms associated with the icequakes on a glacier. This work r epr esents a significant step towards integrating seismological modelling with glaciological interpretation in alpine environments.
SN - 0956-540X
SN - 1365-246X
ER -