Natural time analysis: Important changes of the order parameter of seismicity preceding the 2011 M9 Tohoku earthquake in Japan

Section of Solid State Physics, Physics Department, National and Kapodistrian University of Athens Panepistimiopolis, Zografos 157 84, Athens, Greece, EU and Solid Earth Physics Institute, Physics Department, National and Kapodistrian University of Athens Panepistimiopolis, Zografos 157 84, Athens, Greece, EU

Received: 4 January 2019
Accepted: 26 March 2019

Abstract

Applying the natural time analysis to the Japanese seismic data, we find that almost three months before the 11 March 2011 M9 Tohoku earthquake the order parameter fluctuations of seismicity exhibited an abrupt increase with a natural time scale dependence that has a functional form strikingly reminiscent of the one discussed by Penrose and coworkers in computer simulations of phase transition kinetics using the ideas of Lifshitz and Slyozov. This increase on 22 December 2010, which is shown to be of profound statistical significance by employing the recent method of event coincidence analysis, accompanies increased fluctuations of the entropy change of seismicity under time reversal that obey the Lifshitz-Slyozov-Wagner theory for phase transitions. On the same date the entropy change of seismicity under time reversal is minimized, while the order parameter fluctuations of seismicity exhibit a minimum almost two weeks later.