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Synchronization of earthquake cycles of adjacent segments on oceanic transform faults revealed by numerical simulation in the framework of rate-and-state friction
  • Meng Wei,
  • Pengcheng Shi
Meng Wei
University of Rhode Island

Corresponding Author:matt-wei@uri.edu

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Pengcheng Shi
University of Rhode Island
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Synchronization behavior of large earthquakes (rupture of nearby faults close in time for many cycles) has been reported in many fault systems. The general idea is that the faults in the system have similar repeating interval and are positively coupled through stress interaction. However, many details of such synchronization remain unknown. Here, we built numerical models in the framework of rate/state friction to simulate earthquake cycles on the west Gofar fault, East Pacific Rise. Our model consists of two seismic patches, separated by a barrier patch, constrained by seismic observations. We varied the parameters in the barrier to understand its role on earthquake synchronization. First, we found that static stress transfer can lead to synchronization, opposite to the suggestion by Scholz (2010). Second, the width of the barrier is more important than its strength. When the barrier is narrow enough (no more than half width of the seismic patch in our models), the system can achieve synchronization even with a very strong barrier. Third, for certain simulations, the interaction between the two seismic patches promotes partial rupture in the seismic patches and leads to complex behavior: the system switches from synchronized to unsynchronized over 10-20 cycles. Moreover, the average seismic ratio of the entire fault can be quite low, ranging between 0.2-0.4 because of the barrier patch. We suggest that the existence of large barrier patches contributes significantly to the well-observed low seismic ratio on oceanic transform faults.
Jan 2021Published in Journal of Geophysical Research: Solid Earth volume 126 issue 1. 10.1029/2020JB020231