Complexity in the Earthquake Cycle Increases with the Number of Interacting Patches

Contribution of Viscoelastic Stress to the Synchronization of Earthquake Cycles on Oceanic Transform Faults

“…Without incorporating the viscoelastic mantle, the two asperities in general cannot achieve synchronization (Figure 2). More specifically, when the ratio of barrier width to asperity length is 0.5 (barrier width ℓ VS = 10 km), the fault system under all different initial conditions exhibits a complex behavior showcasing a wide range of earthquake sizes (Figures 2a1–2a8), possibly due to strong stress perturbation from enhanced slip and creep waves in the VS barrier (Kato, 2020; Lui & Lapusta, 2016, 2018; Wei & Shi, 2021). When the ratio of the barrier width to the seismic patch length is 1.0 (barrier width ℓ VS = 20 km), the fault system exhibits a more regular pattern as no smaller earthquakes (except in the beginning when C right = 3.0) occur to disrupt the cycles (Figures 2b1–2b8), presumably due to reduced mechanical coupling by afterslip between the two asperities.…”

“…With a characteristic weakening distance of 8 mm and the other parameters considered, we obtain Ru = 4.9, corresponding to a regime of quasi‐periodic bilateral ruptures for isolated square patches. However, more complexity spontaneously appears for rectangular patches (Hirose & Hirahara, 2002) and with interactions among multiple patches (Kato, 2020; Lui & Lapusta, 2016, 2018). Subsequently, we vary the barrier width ℓ VS to study how viscoelastic stress interaction affects the earthquake cycles as a function of separation distance.…”

Fault Slip Behaviors Modulated by Locally Increased Fluid Pressure: Earthquake Nucleation and Slow Slip Events

“…In these studies, the selection of fault slip behaviors is mainly controlled by the spatially averaged values of frictional parameters. Some studies suggest that fault slip behaviors depend on the asperities/barriers on the fault (Ariyoshi et al., 2012; Kato, 2004, 2020; Noda et al., 2013; Weng et al., 2015; Yang et al., 2012). The breakage of the asperities and the interactions between them dominate the fault slip behaviors, including slip modes and seismic cycles.…”