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Approximate estimates of fracture speeds for dry slab avalanches
Author(s) -
McClung D. M.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl022391
Subject(s) - slab , geophone , snow , geology , fracture (geology) , shear (geology) , geotechnical engineering , fracture mechanics , seismology , geophysics , materials science , geomorphology , composite material , petrology
Dry slab avalanches release by propagating shear fractures. It has been suggested that slab wave or fracture speed on horizontal terrain is consistent with the propagation of a flexural wave in the slab. In this note, an alternate proposal is made. Namely, it is proposed that the fracture speed is consistent with dynamic crack propagation speeds from other materials. The theory is compared with an in situ measurement of speed associated with shear fracture propagation in a weak snow pack layer sensed by geophones placed on the surface of a horizontal snow pack. The theory is shown to be consistent with the mechanical properties of alpine snow and known characteristics of slab avalanche release.