Item: HUNTING MACH CONES IN SNOW:SUPERSHEAR FRACTURE & SHOCK FRONT REFRACTION IN LAYERED SLABS
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Title: HUNTING MACH CONES IN SNOW:SUPERSHEAR FRACTURE & SHOCK FRONT REFRACTION IN LAYERED SLABS
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Alexandre Pellet [ ETH Zurich, Switzerland ] [ Univ. Grenoble Alpes, INRAE, CNRS, IRD, Grenoble INP, IGE, 38000 Grenoble, France ]
- Bastian Bergfeld [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ]
- Alec van Herwijnen [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ]
- Johan Gaume [ ETH Zurich, Switzerland ] [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ]
Date: 2026-09-28
Abstract: Supershear crack propagation has recently been identified as an important mechanism in snow slab avalanche release. In this regime, the crack in the weak layer propagates faster than the shear-wave speed of the slab, producing a shock front known as a Mach cone: a striking Doppler-induced signature of supershear fracture. While this phenomenon is well known in earthquake dynamics, its role in snow fracture and avalanche release is only beginning to be explored. For avalanche research and practice, understanding these dynamic fracture processes is important because they may help explain rapid crack propagation over large distances and improve the interpretation of field and experimental observations. Here, we combine numerical simulations and physical snow fracture experiments to investigate supershear fracture in layered snow slabs. Our results show that slab layering has a strong influence on both crack speed and Mach cone geometry. In particular, changes in cone shape and curvature can be explained by wave refraction at interfaces between layers with different mechanical properties. These findings provide new insights into the dynamic processes governing avalanche release and offer a practical framework for detecting and interpreting Mach-cone signatures in future avalanche release experiments.
Object ID: ISSW2026_P1.16.pdf
DOI: https://doi.org/10.15788/1790099442
Language of Article: English
Presenter(s): Johan Gaume
Keywords: snow slab avalanche, crack propagation, supershear fracture, Mach cone, weak layer, propagation saw test, snow stratigraphy.
Page Number(s): 501 - 506
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