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Simulation of Large Earthquake Synchronization and Implications On North Anatolian Fault Zone
  • Eyüp Sopaci,
  • Atilla Arda Ozacar
Eyüp Sopaci
Geoazur

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Atilla Arda Ozacar
Middle East Technical University
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Abstract

The North Anatolian Fault (NAF) has a history of large quasi-periodic large earthquake clusters. This study investigates the phenomenon with a model consisting of three strong velocity-weakening (VW) asperities separated by velocity-strengthening VS barriers in a 2.5D model governed by rate-and-state friction. The results show that the after-slips at the VS barrier control the stress interaction and synchronization; hence, the barrier strength and size are the most important parameters. The static stress transfer can lead to immature ruptures that arrest within the VW asperity, adding complexity to failure times. The asperity size appears insignificant, challenging previous theories linking barrier efficiency to the asperity-barrier size ratios. Such discrepancy suggests that slip type, e.g., slip-pulse or crack-growth, influences the long-term failure time distribution. Even though the state evolution (aging and slip laws) for frictional strength within the RSF framework differ significantly in co-seismic ruptures, they resemble each other for after-slip propagation, highlighting the importance of after-slip propagation and adding robustness to our conclusions. The results from various simulation scenarios suggest that the after-slip extents and duration with the peak slip rates and rupture speeds are the indicators for the synchronization and the predictability of large earthquakes. Despite the simplicity of the governed model, the results can mimic the synchrony of large earthquakes along the NAF, which are disrupted by aseismic creep and complex fault geometries such as releasing bend (e.g., Cinarcik segment), step-overs (e.g., Niksar) and slip partitioning (Duzce-Bolu segments) acting as barriers.
09 Sep 2023Submitted to ESS Open Archive
11 Sep 2023Published in ESS Open Archive