Accéder directement au contenu Accéder directement à la navigation
Article dans une revue

Dependence of the Omori-Utsu law parameters on main shock magnitude: Observations and modeling

Abstract : We examine the dependence on main shock magnitude m of the p and χ parameters appearing in Omori-Utsu formula λ(t, m) = χ × (t + c)−p relating the rate of aftershocks λ at time t after a main shock. Observations point out to a significant increase of p with m, along with a scaling relationship of the form χ ∼ 10 α m . Here we show that these observations can be explained within the framework of the rate-and-state friction model when accounting for realistic levels of coseismic stress heterogeneity on the main fault. We constrain the model parameters in order to recover the trends observed in previous and new analyses of aftershock sequences. The expected ratio of the coseismic stress drop standard deviation to its mean is found to be of the order of a few units for large (m = 7) earthquakes, resulting in a very rough stress field at the small scale, while it is much smoother at small magnitudes (ratio ≃ 0.1 at m = 2). Finally, the influence of afterslip on parameters p and χ is studied to highlight the fact that it can significantly perturb the p(m) and χ(m) relations obtained with the initial afterslip-free model.
Type de document :
Article dans une revue
Liste complète des métadonnées
Contributeur : Pascale Talour Connectez-vous pour contacter le contributeur
Soumis le : lundi 2 août 2021 - 09:11:39
Dernière modification le : mardi 7 septembre 2021 - 15:54:30


Fichiers éditeurs autorisés sur une archive ouverte


Copyright (Tous droits réservés)




S. Hainzl, David Marsan. Dependence of the Omori-Utsu law parameters on main shock magnitude: Observations and modeling. Journal of Geophysical Research, American Geophysical Union, 2008, 113, pp.B10309. ⟨10.1029/2007JB005492⟩. ⟨insu-00354251⟩



Consultations de la notice


Téléchargements de fichiers