On the influence of time and space correlations on the next earthquake magnitude

TL;DR

This paper demonstrates that earthquake magnitudes are correlated with previous events, showing clustering in time, space, and magnitude, which challenges the assumption of magnitude independence in earthquake prediction models.

Contribution

It reveals the existence of magnitude correlations and introduces a dynamical scaling relation that captures complex seismic patterns.

Findings

Earthquake magnitudes tend to be similar but smaller than previous events.

Magnitudes are correlated with spatial and temporal proximity.

A scaling relation reproduces observed seismic correlations.

Abstract

A crucial point in the debate on feasibility of earthquake prediction is the dependence of an earthquake magnitude from past seismicity. Indeed, whilst clustering in time and space is widely accepted, much more questionable is the existence of magnitude correlations. The standard approach generally assumes that magnitudes are independent and therefore in principle unpredictable. Here we show the existence of clustering in magnitude: earthquakes occur with higher probability close in time, space and magnitude to previous events. More precisely, the next earthquake tends to have a magnitude similar but smaller than the previous one. A dynamical scaling relation between magnitude, time and space distances reproduces the complex pattern of magnitude, spatial and temporal correlations observed in experimental seismic catalogs.