講演情報
[SCG56-49]Stochastic Fault Zone Strength As A Driver For The Emergence of Small Repeating Earthquakes★Invited Papers
*Ahmed Elbanna1、Amr Ibrahim2 (1.University of Southern California (USC) and the Statewide California Earthquake Center (SCEC)、2.University of Illinois Urbana Champaign)
キーワード：
Plasticity、Stochasticity、Small Repeating Earthquakes、Friction
Small repeating earthquakes are commonly observed on natural faults, serving as natural laboratories for investigating fault mechanics and earthquake physics. Traditional conceptual and numerical models often reproduce their observed scaling between seismic moment and recurrence time, as well as realistic stress drops, by artificially constraining the size of velocity-weakening fault patches relative to the nucleation length and/or by imposing creep rates lower than those inferred from observations. Here we introduce a new paradigm in which heterogeneous inelastic deformation within fault damage zones spontaneously segments large velocity-weakening patches, enabling the emergence of small repeating earthquakes without imposing restrictive size constraints. Plastic yielding in the heterogeneous damage zone plays a central role in governing rupture dynamics, promoting a complex partitioning of slip into seismic, aseismic, and plastic components. This natural partitioning replicates key observational signatures of small repeating earthquakes. Notably, the model captures the temporal shutdown of active fault segments producing small repeaters, closely mirroring intermittent seismic quiescence observed in regions such as the Parkfield fault zone. This framework sheds new light on the spectrum of fault slip in complex fault zones, offering a novel explanation for the emergence and evolution of small repeating earthquakes.