Identifying the Occurrence Time of a Mainshock by Means of the Minimum of the Seismicity Order Parameter Fluctuations

Abstract

Natural time analysis of seismicity in a candidate area constitutes the cornerstone for the identification of the occurrence time of an impending major mainshock by means of the criticality condition Variance in natural time .Criticality condition This analysis should start upon the initiation of a Seismic Electric Signals activity since it marks the time at which the system enters the critical stage. Critical stageIf geoelectrical measurements Geoelectrical measurements are not carried out, both necessary elements, i.e., the time of the Seismic Electric Signals activity initiation and the candidate area, are not readily available, but they can be replaced by other quantities in view of the advances in naturalNatural time time analysis achieved during the last decade. In particular, the Seismic Electric Signals activity initiation is found to be simultaneous with the appearance of the minimum of the seismicity orderOrder parameter of seismicity parameter fluctuations (explained in Chap. 2 ) whose spatiotemporal fluctuationsSpatiotemporal variation of the order parameter of seismicity reveal an estimation of the candidate area (discussed in Chap. 3 ). Relevant applications are presented here for the identification of the occurrence times of two prominent major earthquakes, i.e., the M8.2 Earthquake, EQ Chiapas Chiapas earthquake on 7 September 2017 and the M9 Earthquake, EQ Tohoku Tohoku earthquake on 11 March 2011. The explanation of the critical conditionVariance in natural time is also recapitulated.Criticality condition