Dynamic Weakening by Acoustic Fluidization during Stick-Slip Motion

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 num...

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Bibliographic Details
Main Authors: Giacco, F., Saggese, L., de Arcangelis, L., Lippiello, E., Pica Ciamarra, Massimo
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2015
Subjects:
Online Access:https://hdl.handle.net/10356/81232
http://hdl.handle.net/10220/39126
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Institution: Nanyang Technological University
Language: English
Description
Summary: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.