Dynamic fracturing by successive coseismic loadings leads to pulverization in active fault zones

Autor: Aben, Frans, Doan, M.-L, Mitchell, Thomas, Toussaint, R, Reuschlé, T, Fondriest, Michele, Gratier, J.-P, Renard, F
Přispěvatelé: Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), University College of London [London] (UCL), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Manchester [Manchester], University of Oslo (UiO), EU FP7 Marie Curie ITN 'FlowTrans', grant agreement 316889NERC grant ref: NE/M004716/1Labex OSUG@2020: ANR10-LABX56, ANR-10-LABX-0056,OSUG@2020,Innovative strategies for observing and modelling natural systems(2010), European Project: 316889,EC:FP7:PEOPLE,FP7-PEOPLE-2012-ITN,FLOWTRANS(2013)
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Journal of Geophysical Research : Solid Earth
Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2016, 121, pp.23. ⟨10.1002/2015JB012542⟩
Journal of Geophysical Research : Solid Earth, 2016, 121, pp.23. ⟨10.1002/2015JB012542⟩
ISSN: 2169-9313
2169-9356
Popis: International audience; Previous studies show that pulverized rocks observed along large faults can be created by single high-strain rate loadings in the laboratory, provided that the strain rate is higher than a certain pulverization threshold. Such loadings are analogous to large seismic events. In reality, pulverized rocks have been subject to numerous seismic events rather than one single event. Therefore, the effect of successive " milder " high-strain rate loadings on the pulverization threshold is investigated by applying loading conditions below the initial pulverization threshold. Single and successive loading experiments were performed on quartz-monzonite using a Split Hopkinson Pressure Bar apparatus. Damage-dependent petrophysical properties and elastic moduli were monitored by applying incremental strains. Furthermore, it is shown that the pulverization threshold can be reduced by successive "milder" dynamic loadings from strain rates of ~180 s-1 to ~90 s -1. To do so, it is imperative that the rock experiences dynamic fracturing during the successive loadings prior to pulverization. Combined with loading conditions during an earthquake rupture event, the following generalized fault damage zone structure perpendicular to the fault will develop: furthest from the fault plane, there is a stationary outer boundary that bounds a zone of dynamically fractured rocks. Closer to the fault, a pulverization boundary delimits a band of pulverized rock. Consecutive seismic events will cause progressive broadening of the band of pulverized rocks, eventually creating a wider damage zone observed in mature faults.
Databáze: OpenAIRE
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