Identification of earthquake precursors in the hydrogeochemical and geoacoustic data for the Kamchatka peninsula by flicker-noise spectroscopy

TL;DR

This study introduces a flicker-noise spectroscopy-based method to identify earthquake precursors by analyzing hydrogeochemical and geoacoustic signals, revealing potential early warning signs days to months before a large quake.

Contribution

The paper presents a novel application of flicker-noise spectroscopy to detect multi-scale precursors in different signals for seismic regions.

Findings

Nonstationarity factor spikes occur 70-50 days before the earthquake in hydrogeochemical data.

Geoacoustic data show precursors at 29 and 6 days prior to the quake.

Method successfully identifies potential earthquake precursors in multiple signals.

Abstract

A phenomenological systems approach for identifying potential precursors in multiple signals of different types for the same local seismically active region is proposed based on the assumption that a large earthquake may be preceded by a system reconfiguration (preparation) at different time and space scales. A nonstationarity factor introduced within the framework of flicker-noise spectroscopy, a statistical physics approach to the analysis of time series, is used as the dimensionless criterion for detecting qualitative (precursory) changes within relatively short time intervals in arbitrary signals. Nonstationarity factors for chlorine-ion concentration variations in the underground water of two boreholes on the Kamchatka peninsula and geacoustic emissions in a deep borehole within the same seismic zone are studied together in the time frame around a large earthquake on October 8, 2001. It is shown that nonstationarity factor spikes (potential precursors) take place in the interval from 70 to 50 days before the earthquake for the hydrogeochemical data and at 29 and 6 days in advance for the geoacoustic data.