New Evidence of Earthquake Precursory Phenomena in the 17 Jan. 1995 Kobe Earthquake, Japan

TL;DR

This study reanalyzes chemical anomalies before the 1995 Kobe earthquake, providing evidence of criticality and log-periodicity in groundwater ion concentrations as precursors, using advanced statistical methods to reject noise-based explanations.

Contribution

It introduces a novel analysis of groundwater chemical data showing critical phenomena and log-periodic patterns as earthquake precursors, supported by rigorous statistical testing.

Findings

Chemical anomalies exhibit criticality and log-periodicity.

Patterns are statistically significant and not due to noise.

Groundwater ion concentrations serve as effective precursors.

Abstract

Significant advances, both in the theoretical understanding of rupture processes in heterogeneous media and in the methodology for characterizing critical behavior, allows us to reanalyze the evidence for criticality and especially log-periodicity in the previously reported chemical anomalies that preceded the Kobe earthquake. The ion ($Cl^-$, $K^+$, $Mg^{++}$, $NO_3^{-}$ and $SO_4^{--}$) concentrations of ground-water issued from deep wells located near the epicenter of the 1995 Kobe earthquake are taken as proxies for the cumulative damage preceding the earthquake. Using both a parametric and non-parametric analysis, the five data sets are compared extensively to synthetic time series. The null-hypothesis that the patterns documented on these times series result from noise decorating a simple power law is rejected with a very high confidence level.