Testing the correlations between anomalies of statistical indexes of the geoelectric system and earthquakes

Geoelectric precursors are considered to be predictors of earthquakes, but this issue is still under debate. The objective of this research is to statistically test the relationship between the geoelectric system and earthquakes. We observed that anomalies of skewness and kurtosis of geoelectric fields may precede large earthquakes. Next, we developed an alarm model of time of increased probability to quantitatively determine their relationship. Performing binary classification and C1–F1 analysis on both statistical anomalies and earthquake occurrences, the alarm model implies that the statistical correlation between the geoelectric system and earthquakes exists with high confidence. We explained the results by critical transition, which refers to the state of a system becoming slower as it recovers from small perturbations when the system approaches critical points. Hence, generic symptoms, such as autocorrelation, variance, skewness, and kurtosis, can vary appreciably. Early warning signals for critical transitions of the geoelectric system might correspond to impending large earthquakes, in agreement with independent suggestions by other authors that appeared very recently. Consequently, we suggest that the critical transition will take place in the crustal system. Furthermore, we establish a standard procedure to examine the relationship between potential precursor indexes and earthquakes.