Universal local versus unified global scaling laws in the statistics of seismicity

TL;DR

This paper demonstrates that a universal scaling law for earthquake recurrence times applies globally and across diverse regions, revealing power-law behaviors with consistent exponents for long times and variable exponents for short times.

Contribution

It shows the universality of the earthquake scaling law across different regions and clarifies the differences between local and global scaling behaviors.

Findings

Universal power-law decay for long recurrence times with exponent ~2.2

Short-time recurrence behavior varies between regions

Global scaling law differs from local, region-specific laws

Abstract

The unified scaling law for earthquakes, proposed by Bak, Christensen, Danon and Scanlon, is shown to hold worldwide, as well as for areas as diverse as Japan, New Zealand, Spain or New Madrid. The scaling functions that account for the rescaled recurrence-time probability densities show a power-law behavior for long times, with a universal exponent about (minus) 2.2. Another decreasing power law governs short times, but with an exponent that may change from one area to another. This is in contrast with a spatially independent, time-homogenized version of Bak et al's procedure, which seems to present a universal scaling behavior.