Self-Organized Criticality in Process of Aftershocks of Lushan Earthquake

The statistical relations of aftershocks following a strong earthquake can give useful information on the dynamical features of seismic processes and the involved geodynamical mechanisms. The sequence of aftershocks of the Lushan Ms7.0 earthquake, occurred on the Longmenshan tectonic zone in Sichuan Province, China, was analyzed. The analyses of magnitude and temporal statistical distributions in the aftershocks sequence described by the Gutenberg-Richter and Omori laws respectively were performed. To provide a possible explanation of these observed distributions, a novel SOC (self-organized criticality) model was developed by introducing stress decay coefficient and anisotropic diffusion factor into the Olami-Feder-Christensen model of earthquakes, and the self-organized criticality properties of this novel model were discussed. The research result shows that the aftershocks of the Lushan Earthquake follow the Gutenberg-Richter and Omori laws, and the power exponents are about 0.766 and 2.52 respectively. The developed model can give a good prediction of the Gutenberg-Richter and Omori laws in Lushan aftershocks together. And simulated results and observations have a high correspondence to indicate that Lushan aftershock is an example of an SOC process.