Deformation bands that lack evidence of macroscopic shear offset form predominantly by volumetric deformation and are therefore called volumetric deformation bands. The volume change may be either positive or negative (Du Bernard et al., 2002; Sternlof et al., 2005) and is expressed by a porosity increase for dilation bands and a porosity decrease for compaction bands, respectively. Aydin et al. (2006) envisioned that there exists an entire spectrum of bands from pure dilation to pure compaction. It has also been suggested that bands with higher porosity may form by the concentration and coalescence of pores without a significant change in the overall volumetric strain (Mukhamediev and Ul'kin, 2011).