Avalanches in anisotropic sheared granular media
GRANULAR MATTER, 11 (4):
243-252 (2009)DOI: 10.1007/s10035-009-0136-4
Abstract
We study the influence of particle shape anisotropy on the occurrence of
avalanches in sheared granular media. We use molecular dynamic
simulations to calculate the relative movement of two tectonic plates.
Our model considers irregular polygonal particles constituting the
material within the shear zone. We find that the magnitude of the
avalanches is approximately independent of particle shape and in good
agreement with the Gutenberg-Richter law, but the aftershock sequences
are strongly influenced by the particle anisotropy yielding variations
on the exponent characterizing the empirical Omori's law. Our findings
enable one to identify the presence of anisotropic particles at the
macro-mechanical level only by observing the avalanche sequences of real
faults. In addition, we calculate the probability of occurrence of an
avalanche for given values of stiffness or frictional strength and
observe also a significant influence of the particle anisotropy.