Simulation of Large Earthquake Synchronization and Implications On North
Anatolian Fault Zone
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.