Achievement

Whether on laboratory or tectonic scales, disordered materials are found to deform in a series of discrete events. These "avalanches" produce power law distributions of acoustic emission in laboratory experiments and a power law distribution of earthquake sizes. In both cases, systems are in the quasistatic limit where the avalanches are well-separated in time. IGERT trainee Mike Salerno has performed the first simulations of the distribution of avalanches that include inertia. He finds a surprisingly universal power law distribution with the number of events of energy E per unit strain decreasing as 1/E. The same exponent is found in 2 and 3 dimensions and with different interaction potentials, but the distribution becomes exponential when traditional energy minimization dynamics are used in simulations. He is currently exploring the origins of this power law. His work resulted in a conference paper during the current reporting year.