Preliminary results concerning the fracture-induced electromagnetic emissions recorded prior to the Mw 6.7 Earthquake on October 25, 2018 south of Zakynthos

In this letter we present preliminary results concerning precursors to the recent significant (Mw 6.7) earthquake (EQ) that took place in the region south of the Greek Island of Zakynthos (October 25, 2018). We show, in terms of fracture-induced electromagnetic emissions (EME), that the Earth system around the focal area was at critical state up to a few hours before the occurrence of the EQ. Importantly, departure from the critical state, in terms of the symmetry breaking phenomenon, was also identified in the EME recorded after the appearance of the last signatures of criticality. The analysis was performed by means of the method of critical fluctuations (MCF).