Spatial Heterogeneity in Earthquake Fault-Like Systems

The inhomogeneity of materials with different physical properties is responsible for a wide variety of spatial and temporal behavior. In this work, we studied an earthquake fault model based on the Olami–Feder–Christensen and Rundle–Jackson–Brown cellular automata models with particular aspects of spatial heterogeneities and long-range stress interactions. In our model some localized stress accumulators were added into the system by converting a percentage of randomly selected sites into stronger sites that are called ‘asperity cells’. These asperity cells support much higher failure stresses than the surrounding regular lattice sites but eventually rupture when applied stress reaches their threshold stress. We found that changing the spatial configuration of those stronger sites generally increased the ability of the fault system to generate larger events, but that the total percentage of asperities is important as well. We also observed an increasing number of larger events associated with the total number of asperities in the lattice.