The role of static stress diffusion in the spatio-temporal organization of aftershocks

TL;DR

This paper explores how static stress diffusion influences the spatial and temporal patterns of aftershocks, demonstrating a power law decay in aftershock density and modeling this behavior through a stochastic approach.

Contribution

It introduces a stochastic model incorporating static stress diffusion to accurately reproduce aftershock spatial distribution and its dependence on mainshock magnitude.

Findings

Aftershock linear density peaks depending on mainshock magnitude.

Power law decay of aftershock density with distance.

Average main-aftershock distance grows as a power law with exponent ~0.5.

Abstract

We investigate the spatial distribution of aftershocks and we find that aftershock linear density exhibits a maximum, that depends on the mainshock magnitude, followed by a power law decay. The exponent controlling the asymptotic decay and the fractal dimensionality of epicenters clearly indicate triggering by static stress. The non monotonic behavior of the linear density and its dependence on the mainshock magnitude can be interpreted in terms of diffusion of static stress. This is supported by the power law growth with exponent $H\simeq 0.5$ of the average main-aftershock distance. Implementing static stress diffusion within a stochastic model for aftershock occurrence we are able to reproduce aftershock linear density spatial decay, its dependence on the mainshock magnitude and its evolution in time.