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A number of electromagnetic candidates of earthquake precursors have been reported, but Rodger and Clilverd (Comment on “Preseismic Lithosphere-Atmosphere-Ionosphere Coupling,” Eos, this issue) comment that their statistical significance has not been verified. Since most of the proposed mechanisms of reported earthquake precursors are controversial, it is true that the first requisite for verification should mainly rely on statistical analysis, as these authors rightly point out. The statistical analysis, in fact, is exactly what concerned researchers are continuously challenging. It is a difficult goal largely because of the limited number of large earthquakes.

In an Eos article [Kamogawa, 2006], some recent promising results that had been statistically studied were reviewed. Pioneering works by Gokhberg et al. [1989] and Molchanov and Hayakawa [1998] were also mentioned even if they were lacking in elaborate statistical analysis. In their comment, Rodger and Clilverd stress that the existence of preseismic subionospheric anomalies is controversial, citing some papers such as those by Michael [1996] and Clilverd et al. [1999]. Although I did not refer to these papers due to the space limitation of the Eos article, I agree with their point.