Reply to “Comment on the ‘Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals’, by R. A. Grant, T. Halliday, W. P. Balderer, F. Leuenberger, M. Newcomer, G. Cyr and F. T. Freund. Int. J. Environ. Res. Public Health, 2011, 8, 1936–1956” from Friedemann Freund, Rachel Grant and Co-Authors

We fully agree with Dr. Vassiliki Katsika-Tsigourakou that there is more than one possible explanation for the wide range of electromagnetic (EM) field bioeffects reported in the literature. In order to generate EM fields electric currents need to flow that oscillate. Currents that flow through the ground also generate electrical potentials. Such potentials can lead to electrochemical reactions at groundwater interfaces such as the demonstrated oxidation of water to hydrogen peroxide [1]. EM emissions and electrochemical reactions are therefore manifestations of the same physical process in the natural environment. Unusual animal behavior before major earthquakes has been reported for centuries. With few exceptions in recent years, when systematic studies of animal behavior were fortuitously underway at the time of a nearby major earthquake, all observations fall under the rubric " anecdotal ". One may argue that every discovery starts with a serendipitous observation, made haphazardly " out of the blue ". To reach a deeper understanding of the underlying causes requires a large investment in time and financial resources. This is particularly true for " rare " events such as those linked to major earthquakes. For our report on the unusual behavior of toads we had the benefit of such a rare coincidence: an ongoing behavioral study of toads in a lake in Italy and the nearby L'Aquila earthquake of 6 April 2009 [2]. In our interpretation we focused on the possibility of electrochemical reactions driven by the OPEN ACCESS