The Global Electric Circuit and Global Seismicity

Sergey Pulinets,Galina Khachikyan

doi:10.3390/geosciences11120491

Abstract

Basing on the catalogue of earthquakes with a magnitude of M ≥ 4.5 for the period 1973–2017, a UT variation with an amplitude of ~10% in the number of earthquakes is revealed and compared with a UT variation in the ionospheric potential (IP) with an amplitude of ~18%. We demonstrate that the amplitude of the UT variation in the number of deep-focus earthquakes is greater compared with that of crustal earthquakes, reaching 19%. The UT of the primary maxima of both the IP (according to modern calculations) and of earthquake incidence coincides (near 17:00 UT) and is, by 2 h, ahead of the classical Carnegie curve representing the UT variation in the atmospheric electric field on the ground surface. The linear regression equation between these UT variations in the number of deep-focus earthquakes and the ionospheric potential is obtained, with a correlation coefficient of R = 0.97. The results support the idea that the processes of earthquake preparation are coupled to the functional processes of the global electric circuit and the generation of atmospheric electric fields. In particular, the observed increase in thunderstorm activity over earthquake preparation areas, provided by air ionization due to radon emanation, yields a clue as to why the global thunderstorm distribution is primarily continental. Another important conclusion is that, in observing the longitudinal distributions of earthquakes against the IP distribution, we automatically observe that all such events occur in local nighttime hours. Considering that the majority of earthquake precursors have their maximums at local night and demonstrating the positive deviation from the undisturbed value, we obtain a clue as to its positive correlation with variations in the ionospheric potential.

Highlights

Considering Wilson’s paper (1921) [1] as an anchor point, we can celebrate the 100th anniversary of the conception of the global electric circuit (GEC)
It should be noted that the impact of conductivity variations on the ionospheric potential (IP) was considered theoretically in Slyunyaev et al (2014) [14]
Interesting would be results describing the variations of the IP outside thunderstorm clouds over seismically active regions in fair-weather conditions

Summary

Introduction

Considering Wilson’s paper (1921) [1] as an anchor point, we can celebrate the 100th anniversary of the conception of the global electric circuit (GEC). The most recent publications demonstrate the trend of searching the different sources of the GEC’s variability, such as natural ground radioactivity and solar activity (Slyunyaev et al, 2015) [6], seasonal variability (Ilin et al, 2019] [7], and spatial variability, considering the ocean’s and land’s contributions to the GEC (Slyunyaev et al, 2019; Ilin et al, 2020) [8,9] It seems that, in this series of publications, too much attention is paid to the formal parametrization of the GEC’s characteristics, rather than to the physical reasons for the observed variability (Ilin et al, 2020) [9]. This paper, is an attempt to understand the physical reasons for such a relationship—at least, qualitatively

Lightning Activity and Earthquakes

Spatial Distribution of Lightning

Carnegie Curve and Earthquakes