  Recently, mechanical tests on ice as well as dislocation dynamics simulations
have revealed that plastic flow displays a scale-free intermittent dynamics
characterized by dislocation avalanches with a power law distribution of
amplitudes. To further explore the complexity of dislocation dynamics during
plastic flow, we present a statistical analysis of dislocation avalanche
correlations and avalanche triggering. It is shown that the rate of avalanche
triggering immediately after any avalanche is larger than the background
activity due to uncorrelated events. This self-induced triggering increases in
intensity, and remains over the background rate for longer times, as the
amplitude of the mainshock increases. This analysis suggests that stress
redistributions and the associated collective dislocation rearrangements may be
responsible for aftershock triggering in the complex process of plastic
deformation.
