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Abstract We develop an earthquake simulator to study the partitioning of seismic/aseismic slip and dynamics of Earthquakes on a Heterogeneous strike‐slip Fault (HFQsim) using a generalized model of a discrete fault governed by static/dynamic friction and creep in an elastic half‐space. Previous versions of the simulator were shown to produce various realistic seismicity patterns (e.g., frequency‐magnitude event statistics, hypocenter and slip distributions, temporal occurrence) using friction levels and creep properties that vary in space but are fixed in time. The new simulator incorporates frictional heat generation by earthquake slip leading to temperature rises, subsequent diffusion cooling into the half space, and time‐dependent creep on the fault. The model assumes a power law dependence of creep velocity on the local shear stress, with temperature‐dependent coefficients based on the Arrhenius equation. Temperature rises due to seismic slip produce increased aseismic slip, which can lead to further stress concentrations, aftershocks, and heat generation in a feedback loop. The partitioning of seismic/aseismic slip and space‐time evolution of seismicity are strongly affected by the temperature changes on the fault. The results are also affected significantly by the difference between the static and kinetic friction levels. The model produces realistic spatio‐temporal distribution of seismicity, transient aseismic slip patterns, mainshock‐aftershock sequences, and a bimodal distribution of earthquakes with background and clustered events similar to observations. The HFQsim may be used to clarify relations between fault properties and different features of seismicity and aseismic slip, and to improve the understanding of failure patterns preceding large earthquakes.
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This content will become publicly available on June 5, 2026
Spatial scale dependence of fault physical parameters and its implications for the analysis of earthquake dynamics from the lab to fault systems
An accurate assessment of seismic hazard requires a combination of earthquake physics and statistical analysis. Because of the limitations in the investigation of the seismogenic sources and of the short temporal intervals covered by earthquake catalogs, laboratory experiments have played a crucial role in improving our understanding of earthquake phenomena. However, differences exist between acoustic emissions in the lab, events in small, regulated systems (e.g., mines) and natural seismicity. One of the most pressing issues concerns the role of mechanical parameters and how they affect seismic activity across boundary conditions and spatial-temporal scales. Here, we focus on fault friction. There is evidence inferred from geodesy, computational simulations and seismological investigations that most large faults are weak and characterized by very low static friction coefficients which are inconsistent with those of smaller faults and laboratory experiments. We support the hypothesis that static friction decreases with fault size due to the presence of fabrics, roughness, structural asperities and network geometry. We also model its scaling behavior as dependent on a few physical properties (e.g., fault fractal dimension). Conversely, dynamic coefficients are not affected by the spatial scale. Mathematical derivations are based on the hypothesis that earthquake onset results from fracture instability controlled by the extremes of fault shear strength. We validate this using a simple model for earthquake occurrence rooted in fracture mechanics, which reproduces key features of major seismicity (i.e., interevent time distribution, clustering and frequency-size relationship).
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- Award ID(s):
- 2109831
- PAR ID:
- 10645627
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Earth and planetary science letters
- ISSN:
- 0012-821X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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