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A simulator of earthquakes and aseismic slip on a large heterogeneous strike-slip fault

Xiaoyu Zhou, & Yehuda Ben-Zion

Submitted September 10, 2023, SCEC Contribution #12871, 2023 SCEC Annual Meeting Poster #047

We develop an earthquake simulator for studying the dynamics of seismicity and seismic/aseismic slip partitioning on a heterogeneous strike-slip fault using a generalized version of a discrete fault governed by static/dynamic friction and creep in an elastic half-space (Ben-Zion & Rice, 1993; Ben-Zion, 1996). Previous versions of the model were shown to produce a variety of realistic seismicity patterns (e.g., frequency-magnitude statistics, hypocenter and slip distributions, temporal occurrence) using static and kinetic friction levels and creep properties that vary in space but are fixed in time. The present study 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 on the local shear stress, with temperature-dependent parameters 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 the temporal distribution of seismicity are strongly affected by the temperature changes and activation energy in the Arrhenius equation. The model can produce realistic spatio-temporal distribution of seismicity, transient deepening of brittle-ductile transition boundary, foreshock-mainshock-aftershock sequences, and a bimodal distribution of earthquakes between background and clustered events similar to observations (e.g., Zaliapin & Ben-Zion, 2013, 2016). The simulator may be used to clarify relations between fault properties and different features of seismicity and aseismic slip, and improve the understading of evolving seismic/aseismic patterns preceeding large earthquakes.

Zhou, X., & Ben-Zion, Y. (2023, 09). A simulator of earthquakes and aseismic slip on a large heterogeneous strike-slip fault . Poster Presentation at 2023 SCEC Annual Meeting.

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