Recent Field Observations Indicating an Earth System in Critical Condition Before the Occurrence of a Significant Earthquake

In this letter, we show, in terms of the fractureinduced electromagnetic emissions (EME) recorded prior to the earthquake of Chania, Greece [(35.50° N, 23.28° E); October 12, 2013; M_w = 6.4] and the seismicity of the area, that there were different evidence indicating the advent of the main shock a few days before its occurrence. Specifically, both the megahertz (MHz) EME and the foreshock seismicity activity came to critical condition a few days before the main shock occurrence. The analysis was performed by means of two independent methods, namely, the method of critical fluctuations and the natural time method, both revealing critical features.