Exploring the relationship between the magnitudes of seismic events

TL;DR

This paper investigates the dependence of seismic event magnitudes on their causal predecessors, providing evidence that triggered events tend to have magnitudes correlated with their mother events, challenging the assumption of independence.

Contribution

The study introduces an analysis of causal relationships in seismic catalogs, demonstrating a conditional dependence of triggered event magnitudes on mother event magnitudes.

Findings

Triggered event magnitudes depend on mother event magnitudes

Higher mother magnitudes increase the likelihood of high triggered magnitudes

There is a statistically significant linear dependence of magnitude means

Abstract

The distribution of the magnitudes of seismic events is generally assumed to be independent on past seismicity. However, by considering events in causal relation, for example mother-daughter, it seems natural to assume that the magnitude of a daughter event is conditionally dependent on the one of the corresponding mother event. In order to find experimental evidence supporting this hypothesis, we analyze different catalogs, both real and simulated, in two different ways. From each catalog, we obtain the law of triggered events' magnitude by kernel density. The results obtained show that the distribution density of triggered events' magnitude varies with the magnitude of their corresponding mother events. As the intuition suggests, an increase of mother events' magnitude induces an increase of the probability of having "high" values of triggered events' magnitude. In addition, we see a statistically significant increasing linear dependence of the magnitude means.