The study of ionospheric anomalies in Japan area during 1998-2010 by Kon et al.: An inaccurate claim of earthquake-related signatures?

► Kon et al. (2011) examine the statistical significance of pre-earthquake TEC anomalies. ► They claim the occurrence of positive TEC anomalies 1-5 days before M > 6 earthquakes. ► Here these claims are investigated by means of the global geomagnetic activity level. ► The results of Kon et al. could be influenced by magnetospheric signals.