Specific variations of the atmospheric electric field potential gradient as a possible precursor of Caucasus earthquakes

The subject of the research is the study of anomalous disturbances of the gradient of electric field potential of the atmosphere as possible precursors of earthquakes. In order to reveal such precursor Dusheti observatory (φ=42.05; λ=44.42) records of electric field potential's gradient (EFPG) of the atmosphere are considered for 41 earthquakes (M≥5.0) occurrence moments in the Caucasus region. Seasonal variations of atmospheric electric field potential gradient and inter overlapping influence of meteorological parameters upon this parameter are studied. Original method of "filtration" is devised and used in order to identify the effect of EFPG "clear" anomalies. The so-called "clear" anomalies are revealed from (−148.9 V/m) to 188.5 V/m limits and they are connected with occurrence moments of 29 earthquakes out of 41 discussed earthquakes (about 71%). "clear" anomalies manifest themselves in 11-day precursor window. Duration of anomalies is from 40 to 90 min.