Multiphysics resonance of reaction-cross-diffusion waves as nucleation mechanism for earthquakes

Abstract

Forecasting of earthquakes has to date been an elusive problem. Statistical methods show some promise in quantifying the nonlinear behaviour of earthquakes and are used for seismic risk assessment and reinsurance of property but the dynamic phenomenon itself is unexplained. Here we propose a fresh approach reliant on multiscale coupled feedbacks from chemical processes through fluid flow, mechanical deformation, and thermal phenomena to capture the instability. As a working hypothesis for an earthquake precursor phenomenon, we investigate the role of the energy release from microstructural modifications on the future fault plane by a resonance phenomenon of feedbacks across scales. In our companion work, presenting the role of release of microstructural power, we have shown that a reaction-cross-diffusion equation can indeed explain Episodic-Tremor and Slip (ETS) events, indicating that mineral dewatering reactions can cause an avalanche of energy release up to geodynamics scale. A particularly interesting solution of the reaction-cross-diffusion equation is the rogue-wave phenomenon where the release of system energy is focussed both in time and space. Here we investigate whether the characteristics of this solution can be considered as a candidate for an earthquake triggering event. In this context a promising avenue for earthquake forecasting could be the monitoring of release of microstructural energy in the form of quasi-soliton waves or the subsequent self-localising soliton wave on global system resonance that sweeps from the far-field into the future location of the earthquake.