Are seismic waiting time distributions universal?

TL;DR

This study compares seismic waiting time distributions in California and Iceland, revealing common features like power-law decay but also non-universal aspects influenced by geological area and epicenter distribution.

Contribution

It demonstrates that while certain features of seismic waiting times are universal, the full distribution varies with geological area and size, highlighting complex spatial dependencies.

Findings

Power-law decay with exponents ~1.1 and ~0.6 for intermediate and short times

Transition point scales with the size of the area

Dependence on geological area and epicenter distribution is non-trivial

Abstract

We show that seismic waiting time distributions in California and Iceland have many features in common as, for example, a power-law decay with exponent $\alpha \approx 1.1$ for intermediate and with exponent $\gamma \approx 0.6$ for short waiting times. While the transition point between these two regimes scales proportionally with the size of the considered area, the full distribution is not universal and depends in a non-trivial way on the geological area under consideration and its size. This is due to the spatial distribution of epicenters which does \emph{not} form a simple mono-fractal. Yet, the dependence of the waiting time distributions on the threshold magnitude seems to be universal.