Can Stochastic Slip Rupture Modeling Produce Realistic M9+ Events?

Abstract

AbstractStochastic slip rupture modeling is a computationally efficient, reduced‐physics approximation that has the capability to create large numbers of unique ruptures based only on a few statistical assumptions. Yet one fundamental question pertaining to this approach is whether the slip distributions calculated in this way are “realistic.” Rather, can stochastic modeling reproduce slip distributions that match what is seen in M9+ events recorded in instrumental time? We focus here on testing the ability of the von Karman ACF method for stochastic slip modeling to reproduce M9+ events. 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 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 produces 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 to show that for the 1960 M9.4–9.6 Chile, 1964 M9.2 Alaska, and 2004 M9.1–9.3 Sumatra events, stochastic slip modeling has the capability to produce ruptures that compare favorably to those events.