Title: Non-equilibrium fluctuations inside a stable granular bed encode information about its mechanical stability

Authors: Soumen Bhukta, Sebanti Chattopadhyay and Sayantan Majumdar

Granular materials are inherently out-of-equilibrium systems. Understanding the yielding and transport behavior of these systems is crucial for a wide range of applications in engineering and large-scale industrial processes. Yielding in disordered granular materials is very complex due to the lack of identifiable structural defects resulting from the absence of translational symmetry. Here, we study the flow of dense granular suspension formed by corn starch and paraffin oil at high volume fractions using rheology and in-situ boundary imaging techniques. This system flows in a shear-banded manner, where the system splits into a static and a moving band. Interestingly, using image processing and statistical analysis, we have found that fluctuations under the flow inside the static portion encode information regarding the onset of yielding. Our study could be important in developing early warning systems for catastrophic phenomena such as landslides, earthquakes, etc.