The focus of this session is on large volume (>106 m3) rock and volcanic debris avalanches and their deposits. Their departure from simple frictional runout relationships makes them peculiar and particularly important to understand; as such events occur more frequently than previously thought as we are becoming better equipped to recognise their deposits. Detailed investigations of rock/debris avalanche sedimentology is the only way to either support, or refute, emplacement models that allow long-runout, and to validate numerical runout codes. To quote Hutchinson (2006), work focused on rock avalanche deposit internal fabric “is likely to prove most valuable and will counteract any tendency for modelling to run ahead of field observations. Every effort should be made to observe and elucidate rock avalanche deposits as fully as possible, making maximum use of natural exposures”.

We aim to bring together researchers across the volcanic and the landslide research communities to compare case studies from around the world, to share and discuss the various field and laboratory techniques employed, and to discuss the ‘known unknowns’ that need addressing through future work. We welcome contributions that detail large landslide deposit sedimentology from any environment, especially those that attempt to link process and sedimentary form, from single exposure to the macro-morphology of entire deposits.

Hutchinson JN (2006). Massive rock slope failure: perspective and retrospectives on state-of-the-art. In: Evans SG, Scarascia-Mugnozza G, Strom AL, Hermanns RL (editors) Landslides from Massive Rock Slope Failure. Nato Science Series. Series IV, Earth and Environmental Sciences 49: 619-662.