A remarkable change of the entropy of seismicity in natural time under time reversal before the super-giant M9 Tohoku earthquake on 11 March 2011

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: 27 July 2018
Accepted: 19 October 2018

Abstract

Here, we analyze in natural time all earthquakes of magnitude (M) 3.5 or larger in Japan from 1 January 1984 until the occurrence of the super-giant M9 Tohoku earthquake on 11 March 2011. We find that two and a half months before this M9 earthquake a pronounced minimum of the entropy change of seismicity under time reversal is observed. Remarkably the exponent α resulting from the detrended fluctuation analysis of the earthquake magnitude time-series exhibits a simultaneous minimum with an unusual low value () indicating an evident anticorrelated behavior. The validity of these findings is supported by the most studied non-conservative self-organized criticality model for earthquakes since it exhibts a non-zero change of the entropy upon time reversal, which reveals a breaking of the time symmetry, thus reflecting the predictability in this model.