Achat d’une acquisition multivoie ultra-rapide pour imager la dynamique de la fracture
Laboratoire(s)/équipe(s) du LabEx OSUG impliqué(e.s) : ISTerre
Porteur du Projet : Philippe Roux
Ultrafast ultrasonic speckle interferometry, an imaging technique derived from elastography, was used in 2011-2012 to follow the dynamics of the interface failure in a friction experiment. Experimental results obtained on a gel characterized two slipping regimes : a slow slip regime associated with depinning events at the interface and a fast rupture regime including supershear ruptures associated with the emission of Mach waves fronts. At the scale of the Earth there are similar dynamics on active faults, either slow slip events or fast (at about the speed of elastic shear waves) ruptures. With the ultrafast echographer, we aim at imaging now the dynamics of the rupture along a heterogeneous interface, i.e. studying the effect of a barrier resisting the slip propagation on the change of velocity propagation and the triggering of secondary rupture fronts by the slip of the barrier. Coupled with piezoelectric sensors, this equipment will help us understanding the high frequency radiation of the subshear or supershear ruptures. In the same time, this technique allows for detecting slow slip events, and for studying their relation the depinning of small contact asperities.
Soutien attribué : 7 500 € en 2014