Correlation between abnormal trends in the spontaneous fields of tectonic plates and strong seismicities

Tectonic activities, electrical structures, and electromagnetic environments are major factors that affect the stability of spontaneous fields. The method of correlating regional synchronization contrasts (CRSC) can determine the reliability of multi-site data trends or short-impending anomalies. From 2008 to 2013, there were three strong earthquake cluster periods in the North–South seismic belt that lasted for 8–12 months. By applying the CRSC method to analyze the spontaneous field E _SP at 25 sites of the region in the past 6 years, it was discovered that for each strong earthquake cluster period, the E _SP strength of credible anomalous trends was present at minimum 30% of the stations. In the southern section of the Tan-Lu fault zone, the E _SP at four main geoelectric field stations showed significant anomalous trends after June 2015, which could be associated with the major earthquakes of the East China Sea waters (M _S 7.2) in November 2015 and Japan’s Kyushu island (M _S 7.3) in April 2016.