Emergence of precursor instabilities in geo-processes: Insights from dense active matter

Understanding earthquake precursors: from subcritical instabilities to catastrophic events

“…In an earlier contribution [9], we investigated multiphysics feedback processes for which the Onsager reciprocal theory provides a phenomenological approach of coupling several dissipative processes. Onsager conceived a linear relationship between the generalised flux J i and the gradient of a generalised thermodynamic force X j .…”

“…As highlighted in [8] in this region an oscillatory relaxation of any small perturbation to the equilibrium state is expected, even in the absence of a reaction. If the cross-diffusion process is coupled with a reaction, this oscillatory response leads to the formation of an 'active zone' in which the microphysics reactions can form propagating network structures well-known from 'active matter' [9].…”

“…In order to analyse the reaction-diffusion cross-couplings from a micro-mechanical perspective, we performed coarse-graining of the Langevin equation between two tightly coupled microprocesses and found it necessary to relax the local equilibrium assumption of Onsager's reciprocal theorem [9]. Onsager's concept is restricted to the ideal assumption of complete isolation of the local system from its surrounding environment.…”

“…Recently [9][10][11] demonstrated the emergence of instability networks in controlled systems analogous to earthquakes (e.g., granular media, high porosity solids). These experiments exhibit features similar to the tensor networks proposed in this study, such as multiscale propagation and amplification of fluctuations.…”

“…Leveraging on a novel RXD formulation for poromechanics [9,[18][19][20][21], we propose a fresh perspective for multiscale interactions. This framework provides insights into dynamic meso-scale processes through a thermodynamic Ansatz, akin to the phase field approach [17], but assigns a physical meaning to the internal length scale.…”