The Order Parameter Fluctuations of Seismicity Are Minimized Before Major Earthquakes

Abstract

We analyze in naturalNatural time analysis of seismicity time the seismicSeismic catalog Japan Meteorological Agency catalog of the JapanJapanese Meteorological Agency by considering all earthquakes of Magnitude of earthquakemagnitude from 1 January 1984 to 11 March 2011 (until the occurrence time of the M9Earthquake, EQ Tohoku Tohoku earthquake) within the area $$\textrm{N}_{25}^{46} \textrm{E}_{125}^{148}$$ , which covers the whole JapanJapanese region. We find that all shallow earthquakes of Magnitude of earthquakemagnitude 7.6 or larger that occurred in JapanJapan during this 27-year period were preceded by minima $$\beta _{W,min}$$ (or simply $$\beta _{min}$$ ) of the fluctuations of the orderOrder parameter of seismicity parameter Variability minimum of seismicity 1 to around 3 months before. These minima are shown to be statistically Statistical significancesignificant by various techniques. Remarkably, the deepest minimum was observed around 5 January 2011, i.e., around two months before the M9 Earthquake, EQ TohokuTohoku earthquake, almost simultaneously with the starting of Earth’s magnetic field anomalous variationsanomalous variations of Earth’s magnetic field mainlyMagnetic field in the z component which imply (according to Maxwell equations)Maxwell’s equations a strong Seismic Electric Signals activity. In addition, a minimum of the orderOrder parameter of seismicity parameter fluctuations of seismicity was observed almost three and a half months before an ultra-deep earthquake on 30 May 2015 in JapanJapan, which is the strongest earthquake ( $$M_W7.9$$ ) after the M9Earthquake, EQ Tohoku Tohoku earthquake on 11 March 2011 and, strikingly, the deepest earthquake ever detected ( https://www.nationalgeographic.com/science/article/deepest-earthquake-ever-detected-struck-467-miles-beneath-japan ).