ABSTRACT. Seismi c sig na ls of ava la nches, rela ted vid eo im ages a nd num e ri ca l m odels were compa red to improve th e cha racteri zati on o f avala nche phenomena. Se ismic d ata and video im ages from two a rtificially released avalanches were a na lysed to obtain more inform ati on abo ut the origin of the sig na ls. Im age p rocessing was used to compare the evolution of one avala nche front a nd the co rres ponding seismic signa ls. A numerica l model was a lso used to simul ate a n avalanche Oow in order to obtain mean-a nd maximum-velocity p rofil es. Pri or to this, the sim ul a ted avala nche was verifi ed using vid eo im ages. The res ul ts indicate th at the seismic signals recorded correspond to cha nges in avala nche type a nd path slope, interacti on with obstacles a nd to phenomena associated with the stopping stage of the avalanche, suggesting that onl y p a rt of the ava lanche was r ecorded. These results account for the seismic signa ls p reviously obtained a uto maticall y in a wide avalanche a rea.