# Minima of the fluctuations of the order parameter of seismicity worldwide

## TL;DR

This study identifies precursory minima in seismicity order parameter fluctuations, occurring about five and a half months before major earthquakes, and proposes a statistically significant prediction method based on these minima.

## Contribution

It demonstrates that minima in seismicity fluctuations reliably precede large earthquakes and introduces a new prediction approach with high accuracy.

## Key findings

- Minima occur ~5.5 months before earthquakes >8.4 magnitude
- Minima are consistent across different major earthquakes
- Proposed prediction method has 100% hit rate and 6.67% false alarm rate

## Abstract

It has been shown [Phys. Rev. E 84, 022101 (2011); Chaos 22, 023123 (2012)] that earthquakes of magnitude $M$ greater or equal to 7 are globally correlated. Such correlations were identified by studying the variance $\kappa_1$ of natural time which has been proposed as an order parameter for seismicity. Here, we study the fluctuations of this order parameter using the Global Centroid Moment Tensor catalog for a magnitude threshold $M_{thres}=5.0$ and focus on its behavior before major earthquakes. Natural time analysis reveals that distinct minima of the fluctuations of the order parameter of seismicity appear {within} almost five and a half months{-on average-} before all major earthquakes of magnitude larger than 8.4. This phenomenon corroborates the finding [Proc. Natl. Acad. Sci. U.S.A. 110, 13734 (2013)] that similar minima of the seismicity order parameter fluctuations had preceded all major shallow earthquakes in Japan. Moreover, on the basis of these minima a statistically significant binary prediction method for earthquakes of magnitude larger than 8.4 with hit rate 100\% and false alarm rate 6.67\% is suggested.