The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence – Archive ouverte HAL

Giuseppe Petrillo 1 Eugenio Lippiello 1 François Landes 2, 3 Alberto Rosso 4

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

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.

  • 1. Università degli studi della 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

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