Abstract:
The natural time
χ is a new time domain introduced by Varotsos
et al in 2001. Novel dynamical features of time series in complex systems can emerge upon self analysis in natural time, which conforms to the desire to extract useful signal information and reduce uncertainty effectively. In this study, we first introduce the natural time method and then select top 30 earthquakes from the catalogue of China Earthquake Networks Center from 1978 to 2014, after that calculate the variance
κ1 and the coefficient of variation
β of the normalized energy released from each earthquake in natural time domain. Taking
κ1 as the order parameter, we qualitatively analyse
κ1 by making use of
β, and further quantitatively analyse
κ1 on that basis afterwards. The results show that the order parameter
κ1 nearly equals to 0.07 from half an hour to months before the main shock and abruptly decreases toward zero when the main shock happenes. Furthermore, we simply discuss the way to select time window in quantitative analysis and some special cases in analysis results. Hence, it seems that the results have a guiding significance for earthquake events retrospective study and earthquake prediction study.