title: Dynamic Weakening by Acoustic Fluidization during Stick-Slip Motion.
abstract: The unexpected weakness of some faults has been attributed to the emergence of acoustic waves that promote failure by reducing the confining pressure through a mechanism known as acoustic fluidization, also proposed to explain earthquake remote triggering. Here we validate this mechanism via the numerical investigation of a granular fault model system. We find that the stick-slip dynamics is affected only by perturbations applied at a characteristic frequency corresponding to oscillations normal to the fault, leading to gradual dynamical weakening as failure is approaching. Acoustic waves at the same frequency spontaneously emerge at the onset of failure in the absence of perturbations, supporting the relevance of acoustic fluidization in earthquake triggering.
authors.affiliation: CNR-SPIN, Department of Physics, University of Naples "Federico II," Naples 80126, Italy.|Department of Mathematics and Physics, Second University of Naples and CNISM, Caserta 81100, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Giacco
authors.affiliation: Department of Industrial and Information Engineering, Second University of Naples and CNISM, Aversa (CE) 81100, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Saggese
authors.affiliation: Department of Industrial and Information Engineering, Second University of Naples and CNISM, Aversa (CE) 81100, Italy.|Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030, USA.
authors.forename: L
authors.initials: L
authors.lastname: de Arcangelis
authors.affiliation: Department of Mathematics and Physics, Second University of Naples and CNISM, Caserta 81100, Italy.|Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030, USA.
authors.forename: E
authors.initials: E
authors.lastname: Lippiello
authors.affiliation: CNR-SPIN, Department of Physics, University of Naples "Federico II," Naples 80126, Italy.|Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: M
authors.initials: M
authors.lastname: Pica Ciamarra