The 17 July 1999 block-and-ash flow (BAF) at Colima Volcano: New insights on volcanic granular flows from textural analysis

► We studied the vertical and lateral variations of grain size and particle shape of block and ash flows at Colima Volcano. ► Grain size variations highlight the segregation mechanisms that acted during transport and deposition of granular flows. ► Particle shape variations highlight the main particle support mechanisms that acted during transport and deposition of BAFs.