169-1 On the use of Discrete Fault Network simulations for time-dependent seismic hazard assessment, application to the Sagaing fault

Session: Advances and Challenges in Seismotectonic Studies in Slow-Deforming Regions

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Abstract:

Despite considerable advancements in our understanding of earthquake dynamics, earthquake forecasting remains a daunting challenge. The 2025 Myanmar Mandalay earthquake is a notable case, as it ruptured a ‘seismic gap’ on the Sagaing Fault, where a large earthquake was anticipated due to the relatively large deficit of slip that had accumulated there. In this study, we conduct long-term simulations of earthquake sequences accounting for the non-planar geometry of the Sagaing Fault system and assess the predictability of earthquakes in these simulations based on the slip-deficit rationale. The simulations demonstrate the influence of geometrical features, such as fault bends and branches, on the rupture sequence and produce sequences that resemble the historical record, including the 2025 event. While the fault geometry remains invariant, the simulation produces successive ruptures with variable extents and slip distributions that occur irregularly. We find that, despite this variability, the ruptures can be reasonably well predicted based on slip-deficit provided that the slip deficit is integrated over a period of  time exceeding the return period of the maximum event (~200 yr in this case). However, the simulations also suggest that the forecast performance may be significantly lower for natural fault systems that exhibit a more chaotic behavior than observed in our simulations. Our work highlights the potential of using earthquake simulators for time-dependent seismic hazard assessment.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7056

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