Deformation mechanisms in granular media

Of interest are mechanisms of deformation localization along deformation bands and joints in sand and sandstone. Deformation bands are planar or curviplanar zones of finite width, usually a few grain diameter in thickness, of deformation. Based on the dominant mode of deformation, we distinguish shear, compaction, and dilation bands. Recently, we have focused on compaction bands.
Pure and shear enhanced compaction bands
Pure (PCB) and shear-enhanced (SCB) compaction bands in Aztec Sandstone at Valley of Fire. Pure compaction bands are typically wavy whereas shear-enhanced compaction bands are planar. Zig-zaggin bands are composed of alternating right- and left-lateral shear-enhanced compaction bands. Pure compaction bands are oriented perpendicular to the maximum principal shortening direction. From Eichhubl et al., 2010.
Three modes of deformation Three modes of deformation localization in granular media (from Du Bernard et al., 2002).
Shear and dilation bands
Shear band (inclined) and dilation bands (sub-horizontal, red arrows) originating at the tips of shear band segments (from Du Bernard et al., 2002). Pen rests on ledge formed by the shear band which is more resistant to weathering compared to the undeformed sand.


Eichhubl, P., Hooker, J. N., and Laubach, S. E., 2010, Pure and Shear-Enhanced Compaction Bands in Aztec Sandstone: Journal of Structural Geology, doi: 10.1016/j.jsg.2010.02.004, v. 32, no. 12, p. 1873-1886. [html abstract, pdf full text]

Aydin, A., Borja, R. I., and Eichhubl, P., 2006, Geological and mathematical framework for failure modes in granular rock. Journal of Structural Geology, vol. 28, no. 1, p. 83-98. [pdf full text]

Davatzes, N. C., Aydin, A., and Eichhubl, P., 2003, Overprinting faulting mechanisms during the development of multiple fault sets in sandstone, Chimney Rock fault array, Utah, USA, Tectonophysics, vol. 363, no. 1-2, p. 1-18. [html abstract, pdf full text]

Du Bernard, X., Eichhubl, P., and Aydin, A. 2002, Dilation bands: A new form of localized failure in granular media, Geophysical Research Letters, vol. 29, no. 24, 2176, 10.1029/2002GL015966. [html abstract, pdf full text]

last update: 02/27/2011

© P. Eichhubl, 2011