The Edge of Stability: From Collective Vibrations to Jamming and Failure in Granular Media

Granular media is observed in a variety of natural contexts. Whether they come in the form of landslides, debris flows, pyroclastic density currents, bed load, fault gouge, or magmatic crystals, they can fail catastrophically and jam. Here we introduce a characterisation that examines collective motion within granular systems to probe their stability as they are pushed towards the point of failure and stoppage. Using particle-resolved simulations, we show that this characterisation gives early indication of weakening prior to external measures. This characterisation is agnostic to the method of destabilisation, whether it be from increasing slope angles or fluid injection. Applying this characterisation to analogue experiments shows that it can easily demarcate between a static deposit, agitated particles, and an actively destabilizing layer, showing promise in using remote signals to probe the stability of natural systems.