Unjamming dynamics: the micromechanics of a seismic fault model

TL;DR

This paper investigates the unjamming transition in granular systems modeled as seismic faults using Molecular Dynamics simulations, revealing micromechanical changes during slip events and how microslips contribute to creep motion.

Contribution

It introduces a two-time force-force correlation function and a susceptibility measure to characterize the micromechanics of stick-slip dynamics in seismic fault models.

Findings

Correlation function reveals micromechanical changes during slips and microslips.

Susceptibility quantifies the magnitude of microslips.

Micromechanical insights help understand creep motion in granular fault systems.

Abstract

The unjamming transition of granular systems is investigated in a seismic fault model via three dimensional Molecular Dynamics simulations. A two--time force--force correlation function, and a susceptibility related to the system response to pressure changes, allow to characterize the stick--slip dynamics, consisting in large slips and microslips leading to creep motion. The correlation function unveils the micromechanical changes occurring both during microslips and slips. The susceptibility encodes the magnitude of the incoming microslip.