Achievement

Many slowly driven systems show highly intermittent and spatially organized dynamics where rearrangements proceed via avalanches. In the context of mechanical systems, a power law distribution of event sizes is observed in acoustic emission from compressed laboratory samples to earthquakes in fault systems at the tectonic scale. The apparent universality of the power law suggests that simulations of simple models may capture the behavior of complex systems. IGERT trainee Michael Salerno has performed simulations on a model glassy system under pure shear. The system evolved through alternating periods of energy storage followed by rapid energy release as bonds broke and rearranged. These earthquakes followed the distribution observed on earthquake fault systems, a significant improvement over earlier models that failed to capture the distribution. Michael showed the key difference is that his simulations include inertia. A paper on this research should be completed in summer 2009.