Spatial heterogeneity in earthquake fault-like systems

TL;DR

This paper investigates how spatial heterogeneity and long-range stress interactions in earthquake fault models influence the size and frequency of seismic events, highlighting the role of asperity distribution and percentage.

Contribution

It introduces a model incorporating asperity cells with higher failure stresses into cellular automata earthquake models, revealing effects on event size and frequency.

Findings

Increasing asperity percentage leads to larger events.

Spatial configuration of asperities affects fault system behavior.

More asperities correlate with more large events.

Abstract

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