The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence

Giuseppe Petrillo (1) , Eugenio Lippiello (1) , François P. Landes (2, 3) , Alberto Rosso (4)

1 Università degli studi della Campania "Luigi Vanvitelli" = University of the Study of Campania Luigi Vanvitelli
2 UP11 UFR Sciences - Université Paris-Sud - Paris 11 - Faculté des Sciences
3 TAU - TAckling the Underspecified
4 LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques

Aftershock occurrence is characterized by scaling behaviors with quite universal exponents. At the same time, deviations from universality have been proposed as a tool to discriminate aftershocks from foreshocks. Here we show that the change in rheological behavior of the crust, from velocity weakening to velocity strengthening, represents a viable mechanism to explain statistical features of both aftershocks and foreshocks. More precisely, we present a model of the seismic fault described as a velocity weakening elastic layer coupled to a velocity strengthening visco-elastic layer. We show that the statistical properties of after-shocks in instrumental catalogs are recovered at a quantitative level, quite independently of the value of model parameters. We also find that large earthquakes are often anticipated by a preparatory phase characterized by the occurrence of foreshocks. Their magnitude distribution is significantly flatter than the aftershock one, in agreement with recent results for forecasting tools based on foreshocks.

Domains: Disordered Systems and Neural Networks [cond-mat.dis-nn]; Geophysics [physics.geo-ph]

Giuseppe Petrillo, Eugenio Lippiello, François P. Landes, Alberto Rosso. The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence. Nature Communications, 2020, 11 (1), ⟨10.1038/s41467-020-16811-7⟩. ⟨hal-02942365⟩