Common dependence on stress for the statistics of granular avalanches and earthquakes

TL;DR

This study uses molecular dynamics simulations to explore how stress influences the statistical behavior of granular avalanches and earthquakes, revealing common dependence on stress and aligning with seismological observations.

Contribution

It demonstrates that stress affects the statistical laws governing avalanches and earthquakes, highlighting a unified dependence that was previously uncharacterized.

Findings

Gutenberg-Richter law holds near critical density

Aftershocks follow Modified Omori law

Exponents decrease with shear stress

Abstract

The statistical properties of avalanches in a dissipative particulate system under slow shear are investigated using molecular dynamics simulations. It is found that the magnitude-frequency distribution obeys the Gutenberg-Richter law only in the proximity of a critical density and that the exponent is sensitive to the minute changes in density. It is also found that aftershocks occur in this system with a decay rate that follows the Modified Omori law. We show that the exponent of the magnitude-frequency distribution and the time constant of the Modified Omori law are decreasing functions of the shear stress. The dependences of these two parameters on shear stress coincide with recent seismological observations [D. Schorlemmer et al. Nature 437, 539 (2005); C. Narteau et al. Nature 462, 642 (2009)].