Acoustic Fluidization via Dynamic Stresses in Fault Zones

Chris Marone has been working with researchers at the University of Toronto to understand acoustic fluidization in fault gouge. The work employs high-speed impact loading, done at the University of Toronto, and dynamic constitutive modeling.

We have the first laboratory observations of acoustic-induced fluidization under seismogenic stresses. The data show a systematic transition from solid-like to fluidized behavior as a function of gouge layer thickness and dynamic stressing rate. Fluidized behavior is characterized by extreme weakening: the flow stress and elastic modulus decrease by a factor of 5 or more relative to solid behavior. The observed reduction in strength could explain aspects of earthquake triggering by dynamic stressing and help understand the apparent weakness of major tectonic fault zones.

A manuscript was submitted to Nature, Feb. 2009 (Xia, K. S. Huang, R. Chen, and C. Marone, Laboratory Observation of Dynamic Weakening in Simulated Fault Gouge and Implications for Earthquakes).

Contact: Chris Marone