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Dynamic earthquake ruptures on multiscale fault and fracture networks

Abstract : Multiscale fault structures consist of macroscopic major fault networks surrounded by mesoscopic and microscopic fracture networks, considered as off-fault damage. Such geometrical complexity of natural fault structure modifies the rupture dynamics, the seismic wave radiation and the overall energy budget associated with earthquakes. Here we propose a continuum-discontinuum approach framework with combined finite-discrete element method (FDEM) to model dynamic earthquake rupture with the coseismic off-fault damage along natural fault networks. We firstly modeled the dynamic earthquake rupture with the coseismic off-fault damage on a single planar fault. We showed the mechanism of dynamically generated off-fault fracture networks, the decrease in rupture velocity and the enhancement of high-frequency radiation in near-field ground motion. The overall energy budget is modified due to the additional radiation, and dissipation of the energy, associated with the secondary off-fault cracks. We then conducted a dynamic earthquake rupture modeling on the 2016 Kaikōura earthquake, which shows a great potential to narrow down a subset of hypothetical rupture scenarios by comparing the displacement field perturbed by the coseismic off-fault damage with the observations. Overall, this work has opened an avenue to model the dynamic earthquake ruptures with the continuum-discontinuum approach framework, which elucidates the effect of coseismic off-fault damage on the earthquake rupture dynamics and has shown the potential of further applications to natural fault systems.
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Contributor : Kurama Okubo <>
Submitted on : Saturday, February 2, 2019 - 6:59:26 PM
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  • HAL Id : tel-02004905, version 1

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Kurama Okubo. Dynamic earthquake ruptures on multiscale fault and fracture networks. Geophysics [physics.geo-ph]. Institut de Physique du Globe de Paris, 2018. English. ⟨tel-02004905⟩

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