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Séminaire ISTerre
(Why) Are there powerlaw earthquakes?
jeudi 10 novembre 2022 - 14h00
Tom de Geus - Physics of Complex Systems Laboratory, École Polytechnique Fédérale de Lausanne---
Laws of friction have been studied since 500 years, yet their microscopic underpinning still eludes us. We do not understand how slip events are nucleated, nor what controls the distribution of their magnitude; questions that are central in earthquake science. The depinning transition has been an attractive theory to think about earthquakes. However, their relation has been questioned, as it has been argued that earthquakes are not powerlaw. I provide a novel framework to capture these phenomena and re-establish the link between earthquakes and critical phenomena, by considering continuum descriptions perturbed by disorder. It predicts the existence of power-law distributed slip events whose size diverges at a critical stress, and that nucleate global slip (massive earthquakes, preceded by fracture-like front) if they extend past a critical length. I confirm these predictions in a minimal model of a frictional interface. In addition, the coupling between the flow properties of the interface and criticality yields a prediction for the relationship between the size and the duration of the avalanche (earthquake).
Equipe organisatrice : Mécanique des failles
Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères