A remarkable change of the entropy of seismicity in natural time under time reversal before the super-giant M9 Tohoku earthquake on 11 March 2011N. V. Sarlis, E. S. Skordas and P. A. VarotsosEPL, 124 2 (2018) 29001DOI: https://doi.org/10.1209/0295-5075/124/29001