In a recent paper, the authors report the analysis of ionospheric TEC data from GPS measurements around the time of the 6 April 2009 L'Aquila earthquake. According to them, an anomalous change in TEC difference from two GPS receivers in central Italy may be explained as related to the earthquake. We have conducted our own independent analysis using the same GPS data. We have shown that in TEC difference there is no evidence of actual seismogenic effects close to the time of L'Aquila earthquake.

Reports of possible earthquake precursors have social responsibility. They motivate the idea that earthquakes may be predicted in the future. Thus, these papers should be convincing about the seismogenic origin of the reported precursors. We have reviewed Febriani et al. (2014). We have shown that the pre-earthquake magnetic changes they reported are not seismogenic but global-scale variations in the geomagnetic field in response to Sun–Earth interactions.