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Vers l'arrêt spontané de la rupture en dynamique de la source : non-élasticité du milieu et loi de friction hétérogène

Abstract : During an earthquake, the rupture grows and propagates on the fault. When it stops, the seism reaches its final size. Understanding what, in natural cases, determines the rupture ability to propagate or stop is a critical issue in seismology, because earthquakes size can span over a wide range, but only the biggest ones are threatful. In this thesis, we study the impacts of several different ways to stop or perturbate the rupture propagation, through numerical dynamic simulations of the earthquake process.

First, we included a limit to elasticity of the bulk surrounding the fault, in ordre to simulate the rupture propagation in a fractured medium, which dissipates a part of the energy released. For the first time, we have included and studied the impact of this dissipation inside a 3D rupture model. In these conditions, the rupture becomes more sensitive to barriers, and consequently stops more easily. The rupture kinematics are remarkably modified : the rupture velocity is slower, and the slip velocity is limited. Surface motions are less important. Thus, plastic behaviour of the bulk shows up as an important phenomena to take into account for seismic rupture modeling.

Second, we studied the impact of a spatial variability of the rupture resistance on the fault. Introducing such an heterogeneity leads to slip profiles shapes that are closer from natural observations, showing off linear trends. Moreover, the rupture propagation and arrest location loose their predictability, as a consequence of the gradual stop of the rupture front on the small barriers included. For a same statistic of barrier size, a wide range of rupture size has been obtained. A power law distribution similar to a Gutemberg-Richter law can be obtained, if the mean fracture energy on the fault is a function of the rupture size, as it has been observed in the calculations including plasticity.

Finally, we studied the scaling between the final slip and the asperity size, using smooth asperity/barrier models. We show that the dynamics control one part of the maximum slip scaling law, and also that the fault segmentation has to be taken into account to fit properly the scaling law.
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https://tel.archives-ouvertes.fr/tel-00328244
Contributor : Sébastien Hok <>
Submitted on : Friday, October 10, 2008 - 8:42:26 AM
Last modification on : Thursday, November 19, 2020 - 3:54:27 PM
Long-term archiving on: : Monday, June 7, 2010 - 6:02:34 PM

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  • HAL Id : tel-00328244, version 1

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Sébastien Hok. Vers l'arrêt spontané de la rupture en dynamique de la source : non-élasticité du milieu et loi de friction hétérogène. Géophysique [physics.geo-ph]. Université Joseph-Fourier - Grenoble I, 2008. Français. ⟨tel-00328244⟩

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