Small World Picture of Worldwide Seismic Events

TL;DR

This study constructs a global seismic network from 1972-2011 data, revealing small-world properties and non-traditional interval distributions, suggesting interconnectedness of worldwide seismic events.

Contribution

It demonstrates that global seismic networks follow a power law with exponential cutoff and exhibit small-world characteristics, indicating interconnected seismic activity across the world.

Findings

Global seismic network follows a power law with exponential cutoff.

The network exhibits small-world properties.

Time intervals between earthquakes follow nontraditional distributions.

Abstract

The understanding of long-distance relations between seismic activities has for long been of interest to seismologists and geologists. In this paper we have used data from the world-wide earthquake catalog for the period between 1972 and 2011 to generate a network of sites around the world for earthquakes with magnitude m $\geq$ 4.5 in the Richter scale. After the network construction, we have analyzed the results under two viewpoints. Firstly, in contrast to previous works, which have considered just small areas, we showed that the best fitting for networks of seismic events is not a pure power law, but a power law with exponential cutoff; we also have found that the global network presents small-world properties. Secondly, we have found that the time intervals between successive earthquakes have a cumulative probability distribution well fitted by nontraditional functional forms. The implications of our results are significant because they seem to indicate that seisms around the world are not independent. In this paper we provide evidence to support this argument.