The power law sensitivity to initial conditions is investigated for self-organized critical (SOC) models within the damage spreading framework. A class of two-dimensional abelian directed models are analyzed. Results for the time evolution of the normalized squared euclidian distance indicate...

In a recent experiment with rice piles [V. Frette et al., Nature 379 (1996) 49] it was observed that the distribution of avalanches presents a power-law behavior for elongated rice, while avalanches for round rice present a characteristic length. These experiments showed that granular piles may...