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Can stochastic slip rupture modeling produce realistic M9+ events?
  • David T Small,
  • Diego Melgar
David T Small
University of Oregon

Corresponding Author:[email protected]

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Diego Melgar
University of Oregon
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Abstract

Stochastic slip rupture modeling is a computationally efficient reduced-physics approximation that has the capability to create any number of unique ruptures based only on a few statistical assumptions. Its simplicity and efficiency make it an attractive and viable option for testing early warning systems, hazard assessments, and infrastructure response studies. Yet a fundamental question pertaining to this approach is whether the slip distributions calculated in this way are “realistic”. More specifically, can stochastic modeling reproduce slip distributions that match what is seen in M9+ events recorded in instrumental time? Here, we start with the 2011 M9.1 Tohoku-oki earthquake and tsunami where we test both a stochastic method with a homogeneous background mean model and a method where slip is informed by an additional interseismic coupling constraint. We test two coupling constraints with varying assumptions of either trench-locking or -creeping and assess their influence on the calculated ruptures. We quantify the dissimilarity of slip distribution between the 12,000 modeled ruptures and a slip inversion for the Tohoku earthquake. We also model tsunami inundation for over 300 ruptures and compare the results to an inundation survey along the eastern coastline of Japan. We conclude that stochastic slip modeling can produce ruptures that can be considered “Tohoku-like”, and inclusion of coupling can both positively and negatively influence the ability to create realistic ruptures. We then expand our study and show that for the 1960 M9.4-9.6 Chile and 2004 M9.1-9.3 Sumatra events, stochastic slip modeling has the capability to produce realistic ruptures.