HR: 1340h
AN: S43A-1056    [Abstracts]
TI: Rupture Dynamics: Effect of Small Size Strength Heterogeneity on Earthquake Size, Slip Distribution and Rupture Velocity.
AU: * Hok, S
EM: sebastien.hok@obs.ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier, CNRS, Maison des Geosciences, 1381 rue de la piscine, BP53, Grenoble cedex 9, 38041 France
AU: Campillo, M
EM: michel.campillo@obs.ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier, CNRS, Maison des Geosciences, 1381 rue de la piscine, BP53, Grenoble cedex 9, 38041 France
AU: Cotton, F
EM: fabrice.cotton@obs.ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier, CNRS, Maison des Geosciences, 1381 rue de la piscine, BP53, Grenoble cedex 9, 38041 France
AU: Manighetti, I
EM: isabelle.manighetti@obs.ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier, CNRS, Maison des Geosciences, 1381 rue de la piscine, BP53, Grenoble cedex 9, 38041 France
AU: Favreau, P
EM: pfavre@ipgp.jussieu.fr
AF: Departement Sismologie, Institut de Physique du Globe de Paris, 5 place Jussieu, Paris, 75005 France
AB: Geological data and kinematic inversions of seismological data show that the overall shapes of slip profile along strike present long linear slopes (Manighetti et al., J. Geophys. R, 2005). Rupture dynamics of a homogeneous friction properties fault do not lead to such slip distribution. We tried to retrieve this feature using a direct modelling of earthquake rupture, performing 3D simulations with spontaneous rupture initiation, dynamic rupture propagation, and finally, self rupture arrest (without a priori knowledge of the final size of the event). This last characteristic was obtained by imposing fault resistance to be infinite on some randomly sized and localized small patches. We found that small size heterogeneities, which cannot be identified by kinematic inversions using low frequency signal and hence only describing large-scale properties of earthquakes, might have a great influence on the characteristics of the rupture: -For statistically identical random realizations of barrier distribution, we obtain a great variability of event size, with a majority of small events and a few realizations leading to the entire fault rupture. -The arrest of the rupture by the distributed barrier leads, in general, final slip distribution to decay almost linearly from the zone of maximum slip. -Whereas, on an homogeneous model, one could observe a jump from subshear to supershear rupture propagation velocity, with small barriers but the same slip-weakening law parameters (stress drop, strength excess & Dc), the rupture can keep propagating at subshear velocities.
DE: 7209 Earthquake dynamics (1242)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Seismology [S]
MN: Fall Meeting 2005