Investigation of dynamic of unconsolidated materials using two-color digital holography P. Tankam, P. Picart, D. Mounier, J.-P. Boileau, V. Tournat and V. Gusev EPJ Web of Conferences, 6 (2010) 30004 Published online: 10 June 2010 DOI: 10.1051/epjconf/20100630004