The role of gouge production in the seismic behavior of rough faults: A numerical study

TL;DR

This study uses numerical simulations to explore how gouge production from wear influences fault seismicity, including earthquake nucleation, recurrence, and slip behavior, providing insights into fault evolution and seismic potential.

Contribution

It introduces a novel modeling approach combining rate-and-state friction with wear laws to analyze gouge effects on fault seismicity.

Findings

Increased foreshock activity with gouge accumulation.

Recurrence interval shows two distinct phases.

Transition from fast to slow slip rates reduces moment per cycle.

Abstract

Fault zones mature through the accumulation of earthquakes and the wearing of contact asperities at multiple scales. This study examines how wear-induced gouge production affects the evolution of fault seismicity, focusing on earthquake nucleation, recurrence, and moment partitioning. Using 2D quasi-dynamic simulations integrating rate-and-state friction with Archard's law of wear, we model the space-time distribution of gouge and its effect on the critical slip distance. The study reveals a shift from single to multi-rupture nucleation, marked by increased foreshock activity. The recurrence interval undergoes two separate phases: an initial phase of steady increase followed by a secondary phase of unpredictable behavior. Finally, we observe a transition in the moment partitioning from faster to slower slip rates and a decrease in the moment released per cycle relative to the case where no gouge formation is simulated. This research sheds light on wear-driven mechanisms affecting fault slip behavior, offering valuable insights into how the evolution of gouge along a fault affects its seismic potential.